AD-A242 104I~JII~IJll ~I~J I~ 1111 I~II~ESL-TR-88-29*MODIFIERS FOR ASPHALT CONCRETE
A. ABDULSHAFI, K. E. KALOUSH
*RESOURCE INTERNATIONAL, INC..281 ENTERPRISE DRIVE
~CiLV~* WESTERVILLE OH 43081DT
NOVEMBER 1990OC O91
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65502F 3005 0024 I N/A1. TITLE (Include Security Classification)
MODIFIERS FOR ASPHALT CONCRETE
12. PERSONAL AUTHOR(S)Abdulshafi, Abdulshafi A: Kaloush, Kamil E.13a. TYPE OF REPORT 13b TIME COVERED 14. DATE OF REPORT (Year, Month, Day) |15. PAGE COUNT
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FIELD GROUP SUB-GROUP ASPHALT, ASPHALT CONCRETE, FLEXIBLE PAVEMENT, RUTTING,13 02 ASPHALT MODIFIERS, RUBBERS, PLASTICS. CIVIL ENGINEERING
11 0719. ABSTRACT (Continue on reverse if necessary and identify by block number)'In this study, six different types of modifiers belonging to the polymer, elastomer andfiller groups were selected and analyzed. The modifiers were used to develop a screeningcriteria that are able to distinguish among the modified asphalt concrete mixture perfor-
gmance. The screening criteria contained two major items (1) compatibility and aging, set tor ensure that the modifiers are compatible with asphalt cement (AC); (2) potential candidacy. of the modified AC mixture to minimize rutting and fatigue cracking distress. In addition,a cost prohibition factor to exclude modifiers with ineffective life-cycle cost was alsoconsidered.
Testing methods including Marshall criteria, compressive strength, modulus of rebilience andindirect tensile strength were conducted on the modified AC mixtures. Test results couldnot clearly differentiate between the modified mixtures. Two additional and new testingmethods were used: (1) the C*- line integral method to measure the potential for cracking,and (2) the modified compression creep-rutting method to measure the potential for rutting.Test results using these two methods were promising and better able to distinguish the per-formance of the modified AC mixture as related to cracking and rutting pavement problems.
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EXECUTIVE SUMMARY
This study addresses two problems. First, it addresses theevaluation of currently available modifiers for asphalt concretethat can limit distress caused by high-pressure tires and thrustvectoring on airfield pavements. Second, it discusses thedevelopment of innovative testing techniques that could beconsidered for screening and evaluation of potential materialcandidates.
Modifiers were classified by type in six groups, namely,polymer, elastomer, fiber, filler, chemical, and others. Theliterature and manufacturers' information indicated thatmodifiers belonging to the polymer, elastomer and filler groupswere the most promising to solve rutting and cracking distress ofasphalt concrete. Six modifiers belonging to these three groupswere selected to develop a screening criteria that candistinguish among the modified asphalt concrete mixturesperformance. The screening criteria contained two major items:(1) compatibility and aging, set to ensure that the modifiers arecompatible with the asphalt cement (AC); (2) potential candidacyof the modified AC mixtures to minimize rutting and fatiguecracking distress.
Testing methods including Marshall criteria, compressivestrength, modulus of resilience, and indirect tensile strengthwere conducted on the modified AC mixtures. However, the testresults could not clearly differentiate between the modifiedmixtures. Two additional and new testing methods were used: (1)the C* line integral method to measure the potential forcracking, and (2) the modified compression creep-rutting methodto measure the potential for rutting. Test results using thesetwo methods were promising and were able to distinguish andpredict the performance of the different modified AC mixtures.Both methods have good potential application for future screeningof modified asphalt concrete mixtures, since they relate directlyto performance and require simple testing procedures usingstandard testing equipment.
Accesion For
NTIS CRA&IDTIC TAB Unannou.;ced
Justification
/ By ............ .......
I S! *; ,,2
Dist revrs C A
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PREFACE
This report was prepared by Resource International, Inc., 281 EnterpriseDrive, Westerville, Ohio 43081, under contract F08635-87-C-0368, SmallBusiness Innovative Research AF87-067, Phase I, for the Air Force Engineeringand Services Center, Engineering and Services Laboratory, Tyndall Air ForceBase, Florida 32403. This report was submitted as part of the SBIR programand has been published according to SBIR directives in the format in which itwas submitted.
This report summarizes work performed between September 1987 and April 1988.Mrs. Patricia C. Suggs was the AFESC/RDCP Project Engineer.
This report has been reviewed by the Public Affairs Office (PA) and isreleasable to the National Technical Information Service (NTIS). At NTIS, itwill be available to the general public, including foreign nationals.
This report has been reviewed and is approved for publication.
PATRICIA C. SUGG FELIX T. UHLIK III, Lt Col, USAFProject Engineer Chief, Engineering Research Division
CHARLES W. MANZINE, Capt, USAF FRANK P. GALLAGHER III, Col, USAF, BSCChief, Air Base Operating Director, Engineering aid Services
Surfaces Branch Laboratory
v
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TABLE OF CONTENTS
Section Title Page
INTRODUCTION ........................................... 1
A. OBJECTIVES ......................................... 1
B. BAZKGROUND ..................................... .. 1
C. SCOPE .............................................. 2
II TECHNICAL LITERATURE REVIEW ............................ 6
A. TYPES OF MODIFIERS AND THEIR FUNCTIONS ........... 6
1. Polymers (or Plastic) Group ................. 62. Rubber (Elastomer) Group ..................... 73. Fibers Group .................................. 9
a. Polypropylene Fibers .......... ......... 10b. Polyester Fibers ........................ 10c. Steel Fibers........................... 11
4. Fillers...................................... 115. Chemicals.................................... 116. Others... ....................... .......... 127. Commercial Products of the Groups....... . 14
B. SPECIFICATION REQUIREMENT AND SCREENINGOF ASPHALT MODIFIERS ............................... 14
1. Introduction ................................. 142. Building Block of Screening Criteria ........ 16
a. Compatibility and Aging Functions....... 17b. Potential Candidacy Functions .......... 20
(1) The Rutting Problem............... 20(2) The Fatigue Problem............... 20
(a) Rutting Potential Parameter.. 21
(b) The C*-Line Integral......... 23
III RESULTS AND ANALYSES.................................. 27
A. TESTING PROGRAM .................................... 27
B. TEST RESULTS AND ANALYSIS ........................ 31
1. Sample Preparation ........... ............... ..... 312. Viscosity-Temperature Relationship and
Penetration Testing and Results ............. 34
vii
TABLE OF CONTENTS(Concluded)
3. Marshall Criteria Results ...................... 354. Short-Term Material Characteristics ......... 395. Long-Term Potential Candidacy Tests ......... 44
a. Analysis ............................... 44
(1) Cracking Potential ................... 44(2) Rutting Potential .................... 44(3) Creep Compliance After Aging ...... 49
C. DEVELOPMENT OF PHASE I SCREENING CRITERIA ........ 49
IV SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS ............... 54
A. SUMMARY .......................................... 54B. CONCLUSIONS ...................................... 55C. RECOMMENDATIONS .................................. 56
REFERENCES ................................................. 57
APPENDIX A INVENTORY LIST OF MODIFIERS AND SELECTEDFLASH POINT DATA TO ASPHALT CONCRETE ........ 61
APPENDIX B TEST METHODS AND PROCEDURES .................... 69
A. THE CVP METHOD ............................. 70B. THE C*-LINE INTEGRAL TEST ................ 72C. INTERPRETATION OF TEST RESULTS ......... 74
APPENDIX C PHASE I TEST RESULTS ........................ 75
APPENDIX D TEST RESULTS OF AGED SAMPLES .................. 129
APPENDIX E OPTIMUM ASPHALT CONTENT CALCULATIONS ........ 144
viii
LIST OF FIGURES
Figure Title Page
1 Conceptual Framework of Research Approach ........ 32 Determining C* Parameter Schematically ........... 253 Typical C*- Test Set Up .......................... .. 264 Phase I Laboratory Test Program .................. 295 Comparison of Marshall Stability Values
for All Additives ................................ 366 Comparison of Optimum Binder Content
for All Additives ................................ 377 Comparison of Specific Gravity for all Additives. 388 Comparison of Modulus of Resilience .............. 419 Comparison of Indirect Tensile Strength .......... 42
10 Comparison of Unconfined Compressive Strength .... 4311 C -Line Integral ................................. 45
B-1 Incremental Static Rutting-Creep Series .......... 71C-I Compression Rutting-Creep for AC-20 .............. 92C-2 Compression-Rutting-Creep for AC-10 .............. 93C-3 Compression Rutting-Creep for ESL ................ 94C-4 Compression Rutting-Creep for SBS ................ 95C-5 Compression Rutting-Creep for PP ................. 96C-6 Compression Rutting-Creep for ER ................. 97C-7 Compression Rutting-Creep for EVA ................ 98C-8 Compression Rutting-Creep for FCB/AC-20 .......... 99C-9 Compression Rutting-Creep for FCB/AC-10 .......... 100C-10 Marshall Mix Design Curves for AC-20 ............. 103C-11 Marshall Mix Design Curves for AC-10 ............. 106C-12 Marshall Mix Design Curves for ESL ............... 110C-13 Marshall Mix Design Curves for SBS ............... 113C-14 Marshall Mix Design Curves for PP ................ 116C-15 Marshall Mix Design Curves for ER ................ 119C-16 Marshall Mix Design Curves for EVA ............... 122C-17 Marshall Mix Design Curves for FCB/AC-20 ......... 125C-18 Marshall Mix Design Curves for FCB/AC-10 ......... 128D-1 Compression Rutting Creep for AC-20 Aged .......... 135D-2 Compression Rutting Creep for AC-10 Aged ........... 136D-3 Compression Rutting Creep for ESL Aged ............. 137D-4 Compression Rutting Creep for SBS Aged ............. 138D-5 Compression Rutting Creep for PP Aged .............. 139D-6 Compression Rutting Creep for ER Aged .............. 140D-7 Compression Rutting Creep for EVA Aged ............. 141D-8 Compression Rutting Creep for FCB/AC-20 Aged ....... 142D-9 Compression Rutting Creep for FCB/AC-10 Aged ....... 143
ix
LIST OF TABLES
Table Title Page
1 PENETRATION, ABSOLUTE VISCOSITY-TEMPERATURETEST RESULTS ..................................... 30
2 SUMMARY OF MARSHALL CRITERIA TEST RESULTS ........ 333 SHORT-TERM MATERIAL CHARACTERISTICS ................. 404 REGRESSION COEFFICIENTS FOR COMPRESSION-RUTTING-
CREEP TEST OF MODIFIED ASPHALT CONCRETE ............ 475 YIELD POINT OBTAINED FROM CREEP COMPLIANCE TEST
FOR MODIFIED MIXTURES ............................ 486 REGRESSION COEFFICIENTS FOR COMPRESSION-RUTTING-
CREEP TEST OF MODIFIED ASPHALT CONCRETE(AFTER AGING) .................................... 50
7 YIELD POINT OBTAINED FROM CREEP COMPLIANCE TESTFOR MODIFIED MIXTURES (AFTER AGING) ................ 51
A-I INVENTORv LIST OF MODIFIERS TO ASPHALT CONCRETE.. 62A-2 FLASH POINTS DATA FOR SELECTED MODIFIERS AS
PROVIDED BY THE MANUFACTURER ........................ 68C-i CREEP COMPLIANCE DATA BEFORE AGING .................. 76C-2 C*-LINE INTEGRAL TEST RESULTS ....................... 81C-3 INFORMATION OF MARSHALL MIX DESIGN DATA, AC-20... 102C-4 INFORMATION OF MARSHALL MIX DESIGN DATA, AC-10... 105C-5 INFOR4ATION OF MARSHALL MIX DESIGN DATA, ESL ..... 108C-6 INFORMATION OF MARSHALL MIX DESIGN DATA, SBS ..... 112C-7 INFORMATION OF MARSHALL MIX DESIGN DATA, PP ...... 115C-8 INFORMATION OF MARSHALL MIX DESIGN DATA, ER ...... 118C-9 INFORMATION OF MARSHALL MIX DESIGN DATA, EVA ..... 121C-10 INFORMATION OF MARSHALL MIX DESIGN DATA, FCB/AC-20 124C-il INFORMATION OF MARSHALL MIX DESIGN DATA, FCB/AC-10 127D-I CREEP COMPLIANCE DATA AFTER AGING ................... 130
SECTION I
INTRODUCTION
A. OBJECTIVES
The specific objectives of this research study of modifiersfor asphalt concrete are:
1. To investigate the validity and effectiveness of newtechnological materials in limiting distress due tohigh-pressure tires and thrust vectoring on airfieldpavements.
2. To design a laboratory experimentation program tosupport comparative analyses for potential materialcandidates. Innovative testing techniques could beconsidered for screening and evaluation purposes.
B. BACKGROUND
Current and future trends toward increased tire pressure andthrust vectoring on airfield pavements are dictated by severalfactors. The main two factors are: (1) geometrical requirementsfor short takeoff and landing (STOL), and (2) change in loadingconditions as associated with the state-of-the-art development ofAir Force aircraft design, operation, and maneuver techniques.Several types of dist--ess and premature failures have becomeevident on the airfield pavements. Excessive tire pressure andloading result in rutting, raveling, and fatigue cracking whilethe increased tractions result in slippage (or shear) andtransverse cracking. The ultimate result is reduced servicelife, increased maintenance and rehabilitation (M&R) costs, andobstruction to the timely operational needs of the airfieldfacility.
The problem is not related to structural design as much asit is to mixture design. For instance, increasing the topasphaltic layer thickness may solve the fatigue cracking problem;however, it will also enhance the potential for development ofrutting. The solution lies fundamentally in improving thebehavior of the asphaltic mixture under the loading and environ-mental conditions cited previously. The literature indicatesthat asphalt cement (AC) mixtures will not provide adequateperformance under conditions of increased tire pressure andsurface shear loading unless additives and/or admixtures areused. Otherwise, an alternative binder should be used. Thesearch for a new binder or even modification of the AC mixtureswill pose a mixture design problem. Marshall design criteriathat can assure adequate performance of AC mixtures may not bevalid with the modified mix. The set of quality control and
I
_ssurance limits will need to be revised. New, innovativetesting methods, commensurate with the new materials and tech-nological developments, need to be incorporated in the mixturedesign method as well as the quality control program duringconstruction.
Through new technology and material innovations, a widevariety of additives, admixtures, and alternative binders havebeen introduced to the marketplace with potential solutions forthe material-performance requirements. However, research onthese new products, as well as feedback on limited field trials,have not been completed. There is a need to investigate theshort-term and long-term characteristics of the modified mix, inaddition to consideration of other factors, such as compatibilitywith the asphalt cement. Moreover, traditional testing might notbe sufficient to compare the engineering behavior of the newmaterial system; appropriate innovative testing techniques mustalso be introduced. Results of the laboratory investigation ofthe new material system may require changes in the currentspecification and quality control program.
Several questions must be answered by the asphalt additivesstudy; the most important are:
1. What are the currently available asphalt modifiers usedto minimize rutting and fatigue cracking of flexiblepavement? Could those modifiers be grouped by func-tionality?
2. What are the most effective means to compare thesemodifiers quantitatively, considering both engineeringand economic factors?
3. Given a project with selected modifier, what is thequality control testing scheme to be used duringconstruction?
The Phase I investigation of this study is geared towardanswering Question 1 and part of Question 2. The study proposedfor Phase II will enable answering Question 3 and consider thecost-effectiveness of Question 2. It will also result in thedevelopment of guideline specifications as well as a totalcomputerized system for generating an optimal set of solutions toaid the decision maker on cost-effective uses of modifiers.Figure 1 illustrates the two phases within the conceptualframework of this study.
C. SCOPE
To meet the objectives, the following scope of work isidentified for this research study:
2
Additives Admixtures
Miscella- Filler Chemical Fibrous Polymer and Asphaltneous and group group group elastomer groupothers group
- -- - - - Screening criterion
(_ost prohibition factor compactability, potential candidacy test)
PHASE I Design of experiment 1(feasibility study) for potential candidate
materials.J
Short-ter= characterizati'ni
PHASE II Laboratory(development and Experimentationimplementation)
Long-term chuaracterizaclon
Model model for each
Budget Multiattribute PerformanceContrantsoptimization Constraints
[ Ranked optimalsolution (selectionset)
Figure 1. Conceptual Framework of Research Approach.
3
1. Investigate the mode of failures in asphaltic mixturesdue to high-pressure tires and thrust vectoring.
2. Interrelate the above modes of failure to fundamentalmaterial system properties and establish testingprogram parameters.
3. Conduct a literature search on new materials' charac-teristics and a market survey on those materials withpotential for the above specific application.
4. Conduct an initial testing program on selected productsto comprehend Item 3.
5. Screen the materials for selection of potentialcandidates using economical measures and laboratorytesting results criteria.
6. Prepare and submit a report on the findings of theabove study.
This study addresses two distinct problems. First, it ad-dresses the engineering evaluation of new, innovative materialsthat can limit distress severity and extent caused by high-pressure tires and thrust vectoring. Second, it discusses thedevelopment of a selection criterion, given different modifiers'solution alternatives and their effectiveness, cost, and perfor-mance.
The first problem is approached through stochastic modelingtechniques, conducting a balanced experimental design andutilizing innovative testing methods (e.g., comboviscoplasticitytesting, C*-line integral) as "screening windows" for the newmaterial/mixture systems. The potential candidates are thenfurther evaluated by conducting a comprehensive laboratory/fieldtesting program accounting for both short-term and long-termperformance characteristics. The potential candidates must meetthe screening criteria of the group to which they belong.Laboratory-simulated modes of failure should include rutting,fatigue, and thermal cracking, as well as freeze-thaw durabilitytesting. The interrelation of these modes of distresses tomaterial properties is the key factor in the diagnosis/solutionprocess of the problem. All the above modes of distress relatedirectly to the shear stress/strength characteristics of theasphaltic material system in which cohesion and internal frictionof the asphalt concrete mixtures and/or the AC binder are thematerial system parameters to be investigated. Additives areused to modify or alter specific asphalt cement physical and/orchemical characteristics, while admixtures do the same, but forasphalt concrete mixtures.
4
The second problem is approached by utilizing a mathematicalprogramming system such as optimization. In this system, a life-cycle cost model is developed to include initial constructioncosts (including material, production, and modifications tooperation), expected maintenance and rehabilitation actions andtheir costs, salvage value, and service life (determined fromlaboratory/field test data). A multiattribute objective functionwill be formulated to minimize costs, subject to controlledbudget and target performance standard. The idea is to be ableto quickly and efficiently assess the impacts of varying scenar-ios of budget and performance constraints on the resultingselection process and associated costs.
5
SECTION II
TECHNICAL LITERATURE REVIEW
A. TYPES OF MODIFIERS AND THEIR FUNCTIONS
Currently, over 300 different modifiers are commerciallyavailable; each one is supposed to improve one or more of thefundamental properties of asphalts, yet more new modifiers arebeing introduced to the market. One objective of the Phase Istudy is to categorize these modifiers into groups with commoncharacteristics. Laboratory testing requires identification ofthose modifiers that can solve rutting and cracking problems ofasphaltic mixtures.
The major types of asphalt modifiers could be categorized as
follows:
1. Polymer (or plastics) group
2. Rubber (or elastomers) group
3. Fibers group
4. Fillers group
5. Chemical group
6. Miscellaneous and others.
The following is a brief technical discussion of the above sixgroups with greater emphasis on groups (1) and (2) since thesegroups appear to have significant potential for solving crackingand rutting problems.
1. Polymers (or Plastic) Group
Polymer additives are generally thought of as "plastic"or vinyl-type compounds in comparison to elastomer additives thatare thought of as "rubbery" type material. However, the majorelemental component for both is the same; differences exist as towhether the material is derived from raw material containingrubber, whether certain substances are used (e.g., copolymers),the type of processing method used, and, finally, its contribu-tion to the asphalt cement blend properties. Because the term"polymer" is generic, its use in the literature is confusing.Therefore, an introduction to polymers and the ways of categoriz-ing them is presented here.
Polymers (from the Greek: poly + meros, many parts) arelarge molecules created by joining together many small molecules.
6
The simple compounds from which polymers are made are calledmonomers (mono = one). Polymerization processes occur by twomechanisms, namely the "addition"' and "condensation" processes."Addition" polymers are produced by covalently joining theindividual molecules, producing very long chains. "Condensation"polymers are produced when two or more types of molecules arejoined by a chemical reaction that releases a byproduct (such aswater). Linear polymers are long chains; network polymers arethree-dimensional structures. Both linear and network polymerscould be produced by either the addition or the condensationprocess. Polymers are also categorized by behavior into ther-moplastic, thermosetting, and elastomers. Thermoplastic includeslinear polymers that behave in a plastic manner at elevatedtemperatures but, by the nature of their bonding, allow rever-sible behavior. Thermosetting applies to network polymers formedby a condensation process; the nature of their bonding does notallow reversible behavior because the byproduct molecules arereleased. Elastomers are polymers of intermediate behavior;their most important ability is to absorb enormous amounts ofelastic deformation. For this research study the term, polymer,will include thermoplastics and thermosetting materials, whilethe term, rubber, will include only elastomers derived fromvulcanized* rubber (Reference 1).
The general mechanism for blend improvement is thatpolymers create a lattice within the asphalt cement by combiningsmall molecules into larger ones (Reference 2). The largermolecule lattice is more stable under high and low temperatureand thus resists thermally induced cracking in the winter seasonand permanent deformation or "rutting" in the summer season.Several thermoplastic polymers such as styrene block copolymers,ethylene-vinyl-acetate, and polyethylene are available commer-cially (see Appendix A), as well as thermosetting polymers suchas polychloroprene (neoprene compound), ethylene-propylene dienerubber (synthetic rubber), styrene-butadiene latex, and polyisop-rene (natural rubber), which fall in the category of elastomers.
2. Rubber (Elastomer) Group
This material has been used in two primary applica-tions: (1) rubberized asphalt, to modify the properties ofasphalt cement (AC), and (2) asphalt rubber, to substantiallychange the characteristics of the AC (References 3,4,5,6,7,8,9,10). The normal range of rubber in rubberized asphalt is 3 to5 percent by weight of AC added in the form of powder, latex, or
*Vulcanization is the formation of sulfur bridges between
different chains (sulfur + heat). These cross-links make therubber harder and stronger, and do away with the tackiness ofuntreated rubber.
7
latex emulsions. The normal range of percentages of rubber inasphalt rubber is 15 to 25 percent added mainly in the form ofpowder or crumbs. Rubber is basically of three types: natural,synthetic, or reclaimed. Natural rubber is generally obtainedfrom the sap of several tropical plants (Reference 11) and issupplied in two major forms: liquid latex and powdered or crumbrubber. Synthetic rubber is produced from various types ofmaterials including butyl, styrene-butadiene, and neoprene; it isgenerally supplied in powder or latex form (Reference 12).Reclaimed rubber is usually ground-up scrap rubber and tirerubber, which is generally vulcanized. Generally, devulcanizedscrap rubber is used to produce modifiers for rubberized asphalt,while tire rubber (vulcanized) is used to produce modifiers forasphalt rubber. Devulcanization is a process which alters thematerial characteristics with heat, pressure, or softeningagents. Reclaimed rubber comes from used automobile and trucktires. The rubber in the car tires is usually synthetic rubber;however, truck tires are normally manufactured using a blend ofsynthetic and natural rubber (References 13,14).
Balanced against the economic costs associated with theuse of rubber the following benefits are claimed (References15,16,17,18,19) for the asphalt cement:
a. Increased softening point
b. Increased toughness
c. Increased elastic recovery
d. Increased ductility
e. Increased retention of aggregates (in surfacetreatments)
f. Improved low temperature flexibility
g. Improved durability
h. High resistance to compaction under traffic
i. Decreased bleeding tendency
j. Decreased temperature susceptibility.
The following benefits apply to the mechanical/rheologicalbehavior of asphalts:
a. Improved mixture workability
b. Improved sheer susceptibility
8
c. Improved temperature susceptibility; lower thannormal asphalt
d. Improved ultimate responses: tensile strains,high fracture resistance, high elasticity, lowrutting.
Factors that affect the rubber-improved-asphalt cementproperties include the type and amount of reclaimed rubber, thenature and source of asphalt, temperature and time of heating,amount and time of blending, etc.
3. Fibers Group
Although the use of fibers in other engineeringmaterials has been exploited, not much attention has been givento the use of filamentary fibrous reinforcement in bituminousmixtures. Fibrous materials in filamentary form usually havehigh tensile strength-to-weight ratios and high tensile stiffnessmodu2us-to-weight ratios, as compared to bituminous mixtures. Asthe filament diameter decreases, the probability of flaws withinthe material also decreases. The high ultimate tensile strengthof fibers can be useful, if properly harnessed, in increasing theresistance of paving mixtures to cracking. Also, the presence ofsuch high tensile strength reinforcement may increase the amountof strain energy that can be absorbed during the fatigue andfracture process of the mixtiire. This is the rationale behindemploying high-strength fibers in the bituminous mixtures(Reference 20).
Several authors have noted the advantages that can beobtained from fiber reinforcement of plastic and elasticmaterials. Glass fibers that exhibit elastic behavior up tofailure have been used widely in the reinforcement of both typesof materials.
When the matrix to be reinforced is plastic and thefilamentary fibrous reinforcement is elastic, the balance offorces in the composite can be used to determine the criticallength of fiber. For discontinuous fibers randomly distributedin the matrix, fiber reinforcement is most effective when thefiber axis is aligned parallel to the applied tensile stress(Reference 21).
The above theory has been established experimentallyfor metallic continuous matrices reinforced with metallic orglass fibers. However, it may be only approximately correct forbituminous mixtures, where the particulate character and granularnature of the material is wc1- r1czsognized.
Earlier work on fiber reinforcement of bituminous
mixtures has concluded that:
9
(1) The resistance of mixtures containing short chrysotilefibers to deflection is significantly greater underconcentrated loads than for uniform loading, suggestingimprovement of the resistance of mixtures to shearstresses.
(2) For 3 percent fiber addition, the mixtures onlyretained approximately half of their dynamic loadstiffness.
(3) Fiber-reinforced mixtures showed considerably higherflexibility under static loading (than under dynamicloading), as compared to unreinforced mixtures.
a. Polypropylene Fibers
Research results by Majidzadeh et al., (Reference20) using polypropylene fibers, have indicated that the additionof 0.2 to 0.6 percent of fibers resulted in a high stiffnessmodulus while increasing the asphalt content.
The addition of fibers increases both the fatiguelife of the pavement under load and the amount of asphalt cementrequired to achieve maximum stability. Mixtures contdining 0.2to 0.6 percent fiber exhibited about the same maximum Marshpllstabilities as conventional mixtures but the maximum stabilityoccurred at a higher asphalt content.
b. Polyester Fibers
Research results by Majidzadeh et al., (Reference20) using polyester fibers, have indicated that the addition of0.2 to 0.6 percent of fibers resulted in a decrease in Marshallstability of the asphalt-aggregate mixture. This agrees withpublished research (Reference 22).
The addition of fibers increases the amount ofasphalt cement required to achieve maximum stability. Mixturescontaining 0.2 to 0.6 percent fibers exhibit about the samemaximum Marshall stabilities as conventional mixes; howevc, themaximum stability occurs at a higher asphalt content.
Slightly higher stabilities and lower glows wereobtained with mixtures containing washed fibers as compared tounwashed fibers. However, field tests have shown that washedfibers will cling together, causing difficulties in mixing.Consequently, they are no longer considered for use in asphaltconcrete application. The research results also indicate thatincreasing the fiber content above 0.2 percent decreases themixture strength. However, tensile strain at failure is shown toincrease substantially with increased fiber content when testedat 0.002 inch per minute. This is likely caused by additional
10
asphalt in these high fiber content mixtures. The results offatigue tests on various polyester fiber mixes, a, reported bythe Resource International Laboratory, (Reference 20) indicatessubstantial fatigue life improvement at 0.3 and 0.6 percent fibercontent.
c. Steel Fibers
The literature indicates l{t z- Derience withthe use of steel fibers in asphalt concrete :tures. Like thepolyester and polypropylene fibers, the steel C.Ier is introducedto the asphalt paving mixture at the pugmil.. The resultingasphalt pavement is claimed to display a lcz- fatigue life,increased resistance to rutting, and resist-,ice ts thermallyinduced reflective cracking.
4. Fillers
The literature indicates that there are two mainfunctions of using fillers in asphalt concrete, namely, tocontrol the voids content and/or to control the asphalt cementoxidation. A typical product for the first type is mineralfillers, some of which are totally inert while others impartlimited bonding characteristics. Sulfur, lime, and portlandcements are typical examples of these materials that act asfillers, while at the same time introducing limited bonding.Most other siliceous materials passing Number 200 sieve size areexamples of the inert mineral filler materials.
Fillers that control oxidat'Ion are generally 90 percentor more carbon. A typical example is carbon black, consisting of97 percent pure carbon diluted in flux oil and pressed to formpellets (References 2,23). Recent developments indicate thatcarbon black can also be emulsified and pumped, thus eliminatingthe handling problems. Among other claimed benefits of carbonblack are increased moisture resistance, abrasion, and decreasedtemperature susceptibility.
5. Chemicals
The literature provides a wealth of research regardingthe use of chemical additives in bituminous mixtures. Those aremetal complexes including antistripping agents, Chemkretel,antioxidants, and antidegradant (References 2,23,24). An-tidegradant additives are not currently used in the asphaltindustry but have a wide application in the polymer industry asaging inhibitors. Among the antidegradants' group are diarylam-ine derivatives, thioesters, phosphites, eec. The antioxidantadditives are not used in the asphalt industry because ofproduction problems and/or the use of hazardous material (such aslead) in its manufacturing.
11
Chemkretea is an asphalt-soluble complex mix ofmanganese and organic acid. The recommended dose of addition is2.0 to 5.0 percent by weight, resulting in an increase inviscosity and rapid controlled hardening. Claimed benefitsinclude increased strength and stiffness, decreased temperaturesusceptibility, and improved resistance to rutting and cracking.However, field experience with Chemkreten reveals that thecracking assocated with this product limits its present usedespite the advantages of controlled oxidation and lower cost(Reference 24).
Two classes of chemical additives for use as antistripagents are available: ('. asphalt-activated chemicals and (2)aggregate-activated chemicals. The main .ffect is to increasethe aggregate's asphalt bond. The first class consists of anonpolar hydrocarbon chain with a polar end (usually an amine)that is adder' in (1.2 to 1 percent) by weight of asphalt. Thei'edued surface tension of the asphalt improves the bond with thea-gregates, while the polar end is attracted to the aggregate.The second class consists of a heavy metal soap which, whendissolved in water and applied to the aggregates, results indeposition of metal cations on its surface and improves theresistance to stripping. A typical example of this class is BA-2000 , a water-activated metallo-amine complex, produced byCarstab Corporation. The second class is not as widely used asthe first one.
6. Others
A variety of other modifiers tL, asphalt cement ords;)halt concrete currently exist in the marKetplace either on angxperimental basis or to solve special problems. It is difficultto encounter every one of these additives, or even those belong-ing to the above-cited groups, because the industry is rapidlygrowing and introducing new products and materials with claimedsuperior properties. However, in the following sections some ofthese products are mentioned for information purposes, namely,sulfur, Sulphlexp, fly ash, and antistrip agents. The generalmechanisms are described 'elow.
Sulfur reacts with the asphalt cement to produce twodifferent competitive reactions- dehydrogenation and introduc-tion of the sulfur into the molecules. At its melting point,sulfur polymerizes into long radical chains that may eitherextract hydrogen from the hydrocarbons or react to give a carbon-sulfur bond. In effect, the added sulfur may link or remainunreacted as a colloidal solution. Asphalt, upon reaction withsulfur, may become harder and more brittle or softer and moreductile depending mainly on the temperature, i.e., whether or notsulfur entet-* the molecule. Rheological properties of asphalticmixtures using sulfur indicate that the addition of a sufficientamount of molten elemental sulfur to hot asphaltic mixes
12
increases their fluidity and compatibility (References 25,26).When the mix cools, the sulfur solidifies in the void spacesbetween the asphalt-coated aggregate particles in the exactconfiguration of the voids. Thus, sulfur performs as a conform-ing filler particle and serves to interlock the aggregateparticles, imparting a high degree of mechanical stability to themix (Reference 27).
Sulphlexl is a trade name for a manufactured materialcomposed of approximately 70 percent by we..ght elemental sulfurand 30 percent by weight of a blend of th:-e plasticizers orchemical modifiers: 8 percent vinyltoluene, 12 percent dicyclope-ntadiene, and 10 percent dipentene (Reference 28). Sulphlexabinders are designated as follows: -233 is a flexible asphalt-like binder; -230 is similar to -233, except that it rapidlydevelops rigidity as Portland cement concrete; and -126 isdesignated in between grades.
SulphlexB-233, although composed mainly of sulfur,dissolves 68 percent in trichloroethy.one .ompared to sulfur-extended asphalt (SEA), which has a solubility of about 1.6percent. Limited research testing indicates that asphalt andSulphlexR-233 are miscible in all proportions, implying apractical importance of partial substitution. Sulphlex -233mixtures are extremely susceptible to water damage except whenantistripping agents (such as tall oil pitch) are added (whichimproves stability as well). Hydrated lime has a contreindicatedeffect because of its apparent reaction with the Sulphlex.Other properties of unconfined compressive strength and modulusof resilience indicate harder mixtures below 1400 F, as comparedto those of AC-20. A critical factor in the Sulphlexa analysisis the simulated aging in the Thin Film Oven Test (TFOT), whichindicates a loss of weight of about 3 percent and penetration ofabout 70 percent; no Sulphlexa recovery procedure exists atpresent for better evaluation.
Future development of Sulphlexl formulations intendedas substitutes for asphalt will focus on the development ofsofter binders that will produce mixtures with lower stiffnessvalues. Such binders should improve the fatigue and thermalcracking properties of Sulphlexa concrete.
Fly ash, antistrip agents, cement, and lime have allbeen used as additives to minimize stripping problems. The flyash and antistrip agents have, however, proven to be costeffective as well (References 29,30). Fly ash improves resis-tance to stripping from the presence of available calciun in itsmineralogical mnakeup and also from the fact that it increases thedcnsity of the mixture by functioning as a filler. Other typesof byproduct materials, such as lime kiln dust and clear plantresidue (residue from a pilot copper extraction process), haveproven equally effective in e~nnancing stripping resistance of
13
asphaltic mixtures. In fact, limited laboratory field studiesindicated that a designed combination of the above with cementand lime performed in a satisfactory manner.
The addition of up to 6 percent by weight of asphaltimproved the index of retained strength and increased thedensity; however, the results varied, depending upon asphaltaggregates' properties as influenced by their sources and types,the calcium oxide content of the fly ash, and the permeability ofthe mixture. Several other filler-additives are used, such asbottom ash, lignite coal fly ash, limestone dust filler, etc.
7. Commercial Products of the Groups
Appendix A contains a comprehensive list of commercial-ly available modifiers and lists their manufacturer, description,use, and status. However, it is impossible to list each andevery modifier available in the marketplace because the tech-nological development of these materials occurs very rapidly.Information on commercial modifiers in each of the six groups wascollected in the investigation in Phase I.
B. SPECIFICATION REQUIREMENT ANDSCREENING OF ASPHALT MODIFIERS
1. Introduction
The previous section discussed briefly the mechanismsand functions of the modifiers as related to the behavior ofasphaltic mixtures. However, two questions must be answered:
(1) Given specific requirements of an asphaltic mixture tobe achieved, which modifiers would be most suitable?
(2) Among the suitable ones, which one will give, relative-ly, the best results with regard to strength andperformance?
To answer these questions, an initial feasibility studybased on engineering economic factors is to be conducted. One ofthe main objectives of the feasibility study is to develop anacceptance/rejection screening criterion. This should befollowed by establishing an engineering model (discriminatingfun-' ion) that accounts for both short-term and long-termbehavior (performance) of the different mixtures. Engineeringcharacterization is receiving a lot of attention at present due-o the emergence and introduction of new concepts and technologyii, the pavement industry. Earlier methods of discriminatingbetween asphaltic mixture behavior were based on short-termbehavior such as Marshall criteria, resilient modulus, dynamicmodulus, etc. Those parameters reflect the strength or thestiffness and do not necessarily indicate the material toughness,
14
performance, and/or durability. Many researchers are currentlyinvestigating long-term behavior (fatigue and rutting). Thereare two major areas of difficulty with regard to long-termbehavior. First, no documented mathematical models exist thatcan accurately describe field performance or even laboratorysimulated test performance.
Rutting and fatigue are major field problems. Ruttinghas been extensively studied at the empirical and phenomenologi-cal levels (References 20,25,31), with no attempt to characterizethe asphalt mix as other than linear elastic or viscoelastic.Accumulations of permanent deformation were calculated usingelastic and viscous deformation laws. Thus, it is not surprisingthat poor correlations with actual field performance still exist;however, these correlations could be improved if the appropriateconstitutive law is utilized.
Advances in the fields of material characterization andfracture mechanics necessitated more research investigations inthe area of flexible pavement structure failures, particularlythe development of constitutive relationships that betterreplicate material responses such as viscoelasticity and vis-coplasticity (i.e., viscous elastic-plastic elements combined ina configuration) both with and without yield surfaces. Vis-coelastic characterization of asphaltic materials has beeninvestigated (References 32,33), and computer programs that inputthe creep compliance or relaxation modulus have been implemented(Reference 34). Viscoplasticity with yield surface as a con-stitutive relationship has been developed in the field of solidmechanics and has recently been applied to soils (References35,36).
It was not until recently that a sophisticated distressmodel for rutting was developed for asphaltic mixtures usingconstitutive laws derived from continuum mechanics (Reference37). In the next section, an innovative method to deal withrutting, based upon this recent development, is described.Furthermore, another two models have been developed to describethe fatigue behavior of asphaltic mixtures, the first by A.Abdulshafi and K. Majidzadeh using the path-independent contourJ-integral (Reference 38) and the second by 0. Abdulshafi andMajidzadeh using the time-dependent C*-line integral (Reference39). Both models utilize the recent development in fracturemechanics to deal with time-independent (e.g., elastic, elas-toplastic, plastic) and time-dependent (e.g., viscoelastic)material behavior. The fracture mechanics parameters J and C'have advantages in modeling fatigue over the phenomenologicaldistress functions that are discussed in various sections of thisreport. Refinement, application, and validation of the abovemodels are in the state-of-the art timeframe.
15
The second problem area is that the inclusion ofperformance in the engineering model will require laboratoryexperimentation that consumes an appreciable amount of timebefore any result is seen. If these tests are also required forquality control, then these models will be handicapped by thefact that no assurance of meeting their requirements can beforced in the field. This is the typical problem that caused therationalization for the use of short-term parameters as qualitycontrol indicators for materials/construction as well as perfor-mance.
However, because the laboratory determination of the J-or C*-integral is as simple as Marshall stability with the added
advantage of indicating the fatigue potential, then it is logicalto include it as a performance parameter in the quality controlprogram. In fact, the power of using the C*-line integral todifferentiate between different sulfur-asphalt mixtures andoptimize the percentage of suliur in the mix has been indicatedin the literature (Reference 27). Similarly, a parameter thatindicates the potential of mixtures to exhibit rutting should bedeveloped and incorporated in the quality control scheme.Research in that direction is warranted and is expected todevelop a breakthrough in this problem area.
2. Building Block of Screening Criteria
A variety of commercial n.Ddifiers exist that can solvethe problems of rutting, cracking, and raveling caused byincreased tire pressure and thrust loading. These modifiersbelong to different additive/admixture category types as citedabove. There is a need then to develop a rational "screeningwindow or criteria" to either accept or reject these additives.The screening criteria cover three areas of concern, namely, (1)compatibility and aging, set to ensure that the modifier iscompatible with the asphalt cement at the initial mixing as wellas after aging; (2) potential candidacy, set to ensure that themodified asphalt concrete mixture will perform in the field tomeet the objectives of minimizing rutting and fatigue crackingdistress; and (3) potential for being cost prohibitive, set toexclude modifiers with ineffective life-cycle cost. The firsttwo areas cover the required engineering characteristics of themodified asphalt concrete (AC) mix and are dealt with in thisreport, while the third area covers the cost factors and itsrelation to performance; this area is one of the main focuses ofconsideration of the Phase II study. In the Phase I study, acost limit was set based upon the literature review and theresearchers' experience. The cost limit was that the selectedmodifier should not increase the cost of the in-place asphaltconcrete mixture by more than 25 percent.
16
A brief description on the compatibility and agingfunctions as well as the potential candidacy functions is givennext.
a. Compatibility and Aging Functions
Asphalt cement is the cementing agent component inthe asphaltic mixture. It is a highly complex organic hydrocar-bon material (Reference 40). The most significant fractionaloils of petroleum crude (asphalt cement) are asphaltenes andmaltenes (Reference 41). Asphaltene is the bodying agent.Maltenes consist of nitrogen bases (N), first acidaffins (A,),second acidaffins (A2 ), and paraffins (P). Asphaltenes (A), dueto their high surface activity, absorb a covering sheath ofnitrogen bases as a stabilizer (peptizer) as well as the acidaf-fins acting as a solubilizing agent for the peptized asphaltene.These peptized, solubilized asphaltenes are termed "micelles."The nature and quantity of the absorbed sheath govern the degreeof peptization of the asphaltene. When asphaltenes are well-peptized, with sufficient oil (paraffin) content in the asphalt,the dispersion of the micelles is good and the material behaveslike a true solution with the Newtonian flow characteristics of acolloidal sol (Reference 42). If asphalt has a high asphaltenecontent, relative to the nitrogen bases and acidaffins, then thestate of peptization is poor, the micelles are not well-dispersedin the oil phase, and the material will have the rheologicalcharacter of a non-Newtonian gel (Reference 42). In the secondcase, a linkage or structure compound develops and a viscoelasticmechanical behavior is pronounced in which the elastic effect isattributed to the link structure. Although the sol and gelcolloidal states are the limits of a behavior spectrum, trueasphalts (intermediate sol-gel structure) behave in either aNewtonian or non-Newtonian manner, depending on the shear rateand temperature conditions.
It has been demonstrated (References 41,43) thatasphalt is well-defined by the characteristics of the fiveprimary fractional components: A, N, A1 , A2 , and P, where thegroups are well-distinguished and each contributes to a specificbehavior of the asphalt cement.
To quantify the effects of these components, twoparameters were proposed:
(1) The composition parameter (N+AI)/(P+A2), the ratio ofmore reactive to less reactive fractional components.This parameter has been shown to govern the durabilityof asphalts as measured by the tendency to harden(embrittle) during aging. The limits are:
17
N + A1To control syneresis->0.4< < 1.2 <-To control
P + A2 durability(pellet abrasion test)
(2) The chemical compatibility parameter, N/P, measures thefailure or otherwise of the asphaltene to remain in thehomogeneous solution. The limit for these parametersis:
N> 0.5
P
Aging is thought of as a two-part contribution: aphysical contribution of losing the oil phase by evaporation,which is measured by a volatilization factor; and a chemicalcontrbution of transformation of the most chemically activecomponent (nitrogen bases and first acidaffins) into asphalteneof low molecular weight. The result is chemical instabilityreflected by brittle cracking of the pavement. Rheologicalbehavior of the aging process is measured by the change of theasphalt matrix from Newtonian to non-Newtonian characteristics.
Because flash point is related to the amount ofvolatile material, the flash point test may be used in specifica-tion to control volatility. Dunning and Mendenhall (Reference44) suggest that modifiers should have flash points such thattheir blends with asphalt equals or exceeds at least 4000 F flashpoint. Hence, they recommend a 3920 F Cleveland Open Cup (COC)flash point minimum, which should cause in situ flash points inexcess of 4000 F Pensky-Martens Closed tester (PMC) when blendedwith the aged asphalt. This temperature also controls the safetyof mixing and handling blend mixtures during processing.
As the asphalt cement ages, the chemical balancechanges are mainly in the most reactive components of the maltenephase (N and A1 ), where N changes to A and A1 to N. In fact, theconcentration of asphaltene increases because of the componentsthat arc instrumental in solvating and dispersing the asphaltene.This results in an asphaltene of increased concentration andpolarity dispersed in a maltene of reduced solvent power, thusproducing cracking and failure. The specification, however, isconcerned with the effect on compatibility and durability. Thiswould affect the two parameters as discussed before: com-patibility parameter N/P, which controls syneresis; and composi-tion or reactive parameter (N + AI)/(P + A2 ), which is related todurability. Dunning and Mendenhall. (Reference 44) indicated thatit is possible to have one asphalt which may oxidize fairlyrapidly but does not age because of a relatively low concentra-tion of asphaltenes in a maltene phase of strong solvency power
18
and another asphalt which may oxidize slowly but age rapidlybecause of a high concentration of asphaltenes dispersed in amaltene phase of weak solvency power. For any given asphaltenecomposition and concentration, the higher the solubility parame-ter (the stronger the solvency) of maltenes, the lower theviscosity of the asphalt.
The literature indicates that changes in viscosityand/or penetration could be used as measures for the chemical andphysical balance of asphalt cement (or the modified asphaltcement) upon aging. In the area of recycling it has been shownthat a rensonable measure of the effect of a modifier on an agedasphalt can be established by observing the change in viscosityand penetration (Reference 25). There is some indication thatthe viscosity of treated asphalt is a better indicator of therejuvenating effect than the penetration test (Reference 31).
This idea has been extended to define an agingindex as being the viscosity of the modified asphalt cementdivided by the viscosity of the referenced asphalt cement, withboth aged for the same duration at the same temperature. Formodifiers added to the mixture (not preblended with the asphaltcement), the aging index definition is the same except that thetest becomes the creep compliance rather than the viscosity. Thereason is that creep compliance measures the "mixture" viscosity,which is related to the viscosity of the binder, and representsan indirect measure of blend aging index. Based on the abovediscussion, the compatibility and aging functions will bemeasured by:
g I for additivesgr TH
AI =
JbI for admixtures
-Jr TH
where:
Al = aging index
Ab, Ar = viscosity of AC blends and reference material,respectively
TH = aging of material at temperature T for duration H
19
Jb = creep compliance at long duration for the modifiedAC mixtures
Jr = Creep compliance at long duration for the controlreference mixture
b. Potential Candidacy Functions
Laboratory and field investigations have shownthat the failure of asphaltic mixtures for a given set of loadingand environmental conditions could be due to rutting, cracking(fatigue and/or thermal), or a combination of both. In fact, thesame material could fail under permanent deformation as easily asunder brittle (or ductile) fracture. Failure type will dependupon the prevailing damage mechanisms at the final step ofunstable propagation.
(1) The Rutting Problem
Rutting of flexible pavement is defined asthe depression in the wheel path of a vehicle caused by one ormore of the following mechanisms (Reference 37): densification,viscous flow, and plastic deformation. Some or all of the layersof the flexible pavement contribute to the formation of thesurface rut depth. The definition of rutting has been broadenedto include various empirical, semiempirical, and stochasticmodels. However, these procedures fall short of true representa-tion of the pavement response to loading, especially under trendsof increased load and pressure tires. Several studies andresearchers indicate that the most promising models for ruttingare mechanistic. Early mechanistic models have also beendeveloped but they fall short, because accumulation of permanentdeformation was calculated, using elastic and, in only oneadvanced model, viscous deformation laws. A mechanistic modelhas been developed, accounting for the complete spectrum ofmaterial nonlinearity, and has been used to generate rut depthprediction (Reference 45). In this model, a yield surface instress (or strain) space is hypothesized as a bound to an elasticor viscoelastic region behavior for low stresses, and plasticdeformation may commence once stresses reach that surface.Rutting, in this case, is visualized as the accumulation ofnonrecoverable viscous deformation for low stress levels and theaccumulation of nonrecoverable viscous and plastic deformationfor high stress levels. More details about the test method aregiven in the next section.
(2) The Fatigue Problem
It has been argued that the fatigue life asdetermined from small laboratory specimens could be misleading indetermining the fatigue life of an actual pavement (References
20
20,46). This is because most of the fatigue life of a small,smooth, unnotched specimen will be consumed in initiating a crack(Reference 20,46). Therefore the final stages of crack propaga-tion and ultimate failure become indistinguishable within thedata scatter (References 46,47,48). The question of whether ornot these are typical of field observations cannot be directlyaddressed; however, inconsistent correlations of fatigue lifepredicted from laboratory testing indicate that more research isyet to be done.
To better simulate the failure conditions orto determine where the importance of fracture toughness lies, onemust induce conditions of fracture in the small specimens.Notched specimens must be used to promote early crack growth. Amodel could then be developed to compare notched and unnotchedspecimens, and another model could be developed for crack growth.
In the analysis of the unnotched specimens,cyclic plasticity and energy balance should be the tools by whichthe analysis is effected. On the other hand, the notchedspecimen should be investigated within the framework of localstress analysis, which will directly introduce the elastoplasticfracture mechanics or alternatively the viscoelastic fracturemechanic approach (Reference 45). Details on the C*-lineintegral testing are given in the next section.
Based on the above discussion, the potential
candidacy functions will be measured by:
o C*-line integral To establish the cracking potential
o CVP-Model To establish the rutting potential(combo viscoelastic/plastic)
(a) Rutting Potential Parameter
The following development attempts tobridge part of the existing gap in correlation between laboratoryand field performance by outlining and discussing the developmentof a viscoelastic-plastic constitutive relationship to charac-terize asphalt mixtures and predict rutting.
Rutting, as defined previously, includesthe mechanisms of densification, viscous flow, and plasticdeformation. If no interaction is assumed between thesemechanisms, then the one-dimensional mathematical relationshipthat describes the permanent deformation will be:
p po c(t) + EPL
21
where:
Ep = permanent total deformation
CPO = permanent deformation due to densification;it could be represented by an in-seriesmechanical relaxing spring with constant p.
ev(t) = time-dependent viscous permanent deformation
CPL = time-independent plastic permanentdeformation.
Introduction of the above equation intoa permanent deformation phenomenological model such as:
Ep = N1 N-macc
where:
Ep = average accumulated permanent deformationacc
N = number of cycles at measured permanentdeformation
m = the slope of log 6p - log N relationship
will result in:
ep = K2 (a,t) (e(t) - K1 Nl-m)
VE E't E'- + + if a > ayield, t > 0
:Epo 2 H(Wp)where:
E' El+ t if a < yield, t > 0
Epo 772
K2 (,t) Elif a < Cyield, t = 0
Epo
22
E' E'
+ n 2 if a > ayield' t = 0Epo 1 H(Wp)
E' retarded elastic creep modulus
1
1 1 -Elt+- (i- EXP (- ))
E2 El 771
This model represents a viscoelastic-plastic model that will lead to a general rutting model withemphasis on a method for distinguishing between the contributionof densification and other permanent deformation mechanisms.This capability to distinguish between densification and sheardeformation could enable researchers to identify the uniquemechanism pertaining to each additive using K2 coefficient.However, in this report the method used to investigate thepotential for rutting is to examine two parameters: (1) theyield point cy, and (2) the creep deformation rate (CR). Both ofthese parameters are obtained by drawing a curve between thesteady-state creep deformation iss and stress level. At higherstress levels the variation of the creep deformation rate, ss(the slope of the line for ess versus stress levels) is linear.Hence CR will be uniquely defined. The intercept of CR-line withthe initial slope on the same graph will define the yield point,a y.
(b) The C*-Line Integral
The energy rate interpretation of C* isgiven as the power difference between two identically loadedbodies having incrementally differing crack lengths by:
1 dU*C* = - __
b dawhere:
b = thickness of specimen in crack plane
U* = power.of energy rate for a load P and displacementrate,A
a = crack length.
23
The method of determining the C* parameter experimentally wassuggested by Landes and Begley (Reference 49) and is shownschematically in Figure 2. In this method, multiple specimensare subjected to different constant displacement rates. The load(P) per unit crack plane thickness and the crack length (a) aremeasured as a function of time, as shown in Step 1. This steprepresents the actual data collected during the test. Becausethe tests are conducted at a constant displacement rate, time anddisplacement are the independent variables. Load and cracklength are dependent variables. The data in Step 1 are thencross-plotted to yield the load as a function of the displacementrate (A) (from tests at several displacement rates) for fixedcrack lengths, as shown in Step 2. The area under the curve inStep 2 is the rate of work done, Uk per unit of crack planethickness. This is shown plotted against the crack length, as inStep 3. The slope of the curve in Step 3 is C*. Finally, C* isplotted as a function of the crack growth rate, as shown in Step4 or the crack length is plotted as a function of C*, as shown inStep 5. This method of C* determination is called the multiple-specimen method. Adapting this method for use with asphalticmixtures required the use of the Marshall-type specimen shown inFigure 3 (after Reference 39).
24
aI > a2>03
a 03>
PPT GI
TSTEP I STEP 2
A1 '2 3
U* , 3 C*
0 A,STEP 3 STEP 4
0
¢*
STEP 5
Figure 2. Determining C* Parameter Schematically.
25
U'0)
UU
CL'
44-)
U) rrJ4-)U)
t3) (z % U) U
rc$ Io 0 4 U -4 a
r-I p o r-i -14 U
i 10 E -, En 5 M4-)
U) 04 44M 04- 2
26U
SECTION III
RESULTS AND ANALYSES
In this chapter, test results to support the development ofa screening criteria will be presented, as well as the analysisof applying the screening criteria to selected modifiers. Theresults in this phase of study are used to investigate thefeasibility of utilizing a screening criteria and not as finalmeasures on the engineering characteristics and performance ofthe selected modifiers. To be able to investigate and ascertainthe performance of the selected modifiers, more samples must betested in a planned design of the experiment, as outlined in thePhase II followup study proposal.
A. TESTING PROGRAI
In the Phase I investigation, the following six types ofmodifiers were selected for testing:
Modifier Type Abbreviation
o Elastomer: Synthetic latex ESL
o Block--,'o-Polymer: Styrene-butadiene-styrene SBS
o Plastic: Polyethyleue/polypropylene PP
o Elastomer: Rubber ER
o Plastic: Ethylene--vinyl-acetate EVA
o Filler: Carbon Black FCB
These modifiers were selected, based upon informationobtained from the literature review and further confirmed by themanufacturer's technical data. Information on flash points ofthese modifiers are included in Appendix A, Table A-2. Two typesof asphalt cements are used (AC-10 and AC-20). Selection ofthese types of asphalt cement was based on the manufacturer'srecommendation, review of the literature, and the informationobtained from the Air Force Standards AFM88-6, Chapter 2,"Flexible Pavement Design for Airfields" for area Zones I and II.Limestone aggregates used were obtained locally and complied withthe Air Force specifications for aggregate gradation (cited underwearing-course requirements for the 3/4-inch-down maximum sievesize under the column labeled "high pressures.") The Marshall
27
method of mix design used is also in compliance with the above-cited specification.
Figure 4 presents the Phase I laboratory testing program.The following steps were followed:
1. The six asphalt modifiers were blended with AC-10 andAC-20 separately, and the penetration test was carriedout. Two control AC samples were also tested. Theviscosity/temperature relationship was established forall the blends and the control samples. The initialviscosity index was calculated. Next, the six blendsand the controls were aged in a Thin-Film Oven Test(TFOT) at 325 OF for a period of 5 hours. The vis-cosity of the blends was determined, and the agingindex was calculated. Results were analyzed, and theyand presented in Table 1. Two terms are defined asfollows:
o Aging Factor (AF) = This is the ratio ofviscosity of the blendbefore and after TFOT.
o Aging Index (AI) = This is the ratio ofviscosity of the blend tothe viscosity of thecontrol asphalt cementafter aging in the TFOT.
2. The Marshall method of mix design was used in accor-dance with Air Force specifications to determine theoptimum asphalt content (in this case binder content)for each of the six modified asphalt blends and thecontrol. Based on the Marshall optimum-mix design,several samples were fabricated to carry out thefollowing tests:
a. Modulus of resilience, MR
b. Indirect tensile strength, ay
c. Unconfined compressive strength, qu
d. Creep test on unaged and aged samples, J(t)
e. Rutting potential test using the CVP method
f. Cracking potential test using the C*-line integralmethod.
28
ASPHALT CEMENT
OBTAINAGGREGATES
j "LIMESTONE"
AC
CONTROL MODIFIED A CSAMPLE
VISCOSITY-TEM PENETRATION RTFOTRELATIONSHIP -J
9 MIX DESIGN(MARSHALL)
7 MODIFIERS +
2 CONTROL
OBTAIN
OPTIMUM MIX
[ I RUN
M R ary qu CREEP TEST C W
RUTTING CRACKING
Figure 4. Phase I Laboratory Test Program.
29
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30
Tests a, b, and c are standardized under American Societyfor Testing and Materials (ASTM) specifications. Test d isdetailed in the VESYS IIM User's Manual (Reference 32). Tests eand f are new and thus are outlined in Appendix B.
B. TEST RESULTS AND ANALYSIS
1. Sample Preparation
Initial laboratory work pertained to the preparation ofsufficient asphalt-additive mixture quantity to allow completionof all tests in the testing program. Materials sufficient forthe test program were obtained based on the estimate of asphaltconcrete required for the tests to be performed on each of theselected additives' sample. Sufficient aggregates to completethe testing program and to meet the Air Force gradation specifi-cation were also obtained. The specification used was accordingto Table 7-4 of AFM88-6, "Flexible Pavement Design for Air-fields." The maximum sieve size was 3/4 of an inch and thegradation for the high-pressure wearing course was selected.
The first step of the laboratory portion of the programwas to mix the asphalt and additive mixtures. In all, ninedifferent asphaltic mixtures (blends) were prepared for varioustests. Two of these were regular AC-10 and AC-20 to be used ascontrols. The remaining seven asphalts would contain the specialadditives. As recommended by the manufacturer, the additive,FCB, was used in an AC-10 and an AC-20 mix. The remaining fiveadditives were each mixed with AC-20.
Three of the mixes were prepared by an outside testfacility at the request of the supplier. The PP and FCB addi-tives were sent to Matrecon, Inc., in California, for mixing.The reason given for the PP was the need for a special blenderwhich Matrecon had, and, according to the manufacturer of FCB,the need was for very thorough blending. The remainder of theadditives were mixed in the laboratory at Resource International,Inc., according to the manufacturer's recommendations. General-ly, if the asphalt concrete can be kept at 300 OF, mixing of thepolymer and elastomer additives, as was done at Resource Interna-tional, is no problem. A mixing time of 1/2 to 1-1/2 hours and amixer providing agitation and turnover are adequate. Completeintermixing of the additive and AC is difficult to visuallydetermine, so overmixing is the best choice if there is anydoubt.
The percent addition of each modifier was based on themanufacturer's recommendation. Following are the percentaddition used by weight of the asphalt cement:
31
Modifier Type % by weiQht of AC
ESL 4.0SBS 12.0Pp 5.0ER 3.5EVA 4.0FCB (for both types of AC) 15.0
After all mixing was completed, small quantities of&ach of the nine samples were set aside for viscosity andpenetration tests. Viscosity tests were performed to determineviscosities at 140 OF and 275 OF; the tests were done accordingto ASTM procedure D2171-72 using Cannon-Manning viscometers andconstant-temperature bath. Tests to determine viscosity wereperformed on the new samples and on the same samples that hadbeen aged according to ASTM D1754-85 for Thin-Film Oven Testaging. Penetration tests were performed on the nine samplesaccording to ASTM D5-73. Results of these tests are found inTable 1.
The next step in the laboratory testing program was thepreparation of the Marshall Mix Design tablets to optimize thebinder con-ent. Procedures for testing and data analysis weretaken from Section 7, Bituminous Material Courses, of the U.S.Department of Defense (DOD) "Flexible Pavement Design forAirfields."
A range of 5 to 7 percent binder content by weight waschosen with the binder contents being 5, 5.5, 6, 6.5, and 7percent. Three samples of each binder content of each of thenine asphalt concrete mixtures were prepared. This makes thetotal Marshall tablets prepared initially to be 135. Theaggregates for the tablet preparation were sieved according tothe Air Force specification mentioned previously. After a fewtries the proper weight of graded aggregate was found to give therecommended 2.5-inch height for the Marshall tablet. This valuewas used for the preparation of the 135 Marshall tablets.
Testing according to the Marshall procedure was thenperformed on the samples, and the data were analyzed to determinethe optimum binder content for each of the nine mixtures. ForAC-10, ESL, SBS, ER and FCB/AC-20 mixtures, it was necessary toprepare additional samples at binder content percentage less than5 to determine the optimum stability values. The optimumstability values for these mixtures could not be determined inbinder content range that was selected initially. Marshall mixdesign results are shown in Appendix C. A summary of the resultsare presented in Table 2. Test specimens at optimum bindercontent were then prepared to perform the comparison tests for-c'.cting the best asphalt modifier. Test results are summarizedin the following section.
32
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2. Viscosity-Temperature Relationshipand Penetration Testing and Results
This test was carried out in accordance with thefollowing ASTM standards:
o D-5 : Penetration test
o D-2171: Absolute viscosity
o D-1754: Thin-Film Oven Test (TFOT)
The only deviation from the standard test D-1754 isthat the oven shelf rotates about an axis inclined 100 from thevertical axis. This was done to expose more of the sample totest conditions, as well as to aid in stirring. The penetrationtest was conducted only at the initial conditions, i.e., afterblending the modifiers with the asphalt cement. The viscositytest was carried out before and after aging (i.e., before andafter TFOT). Each time, the absolute viscosity was determined attwo temperatures, 140 OF and 275 OF. When it was not possible totest at 140 OF, viscosity at two other temperatures close to 140OF was measured, and the viscosity at 140 OF was found by curveextrapolation. Before TFOT, all modifiers were tested at 140 OFand 220 OF except SBS which was tested at 160 OF (the SBSmodifier was found to be too viscous at 140 OF). Although thetest could have been performed at 140 OF, very inconsistantresults were seen in the initial tests. After TFOT, all modifi-ers were tested at 160 OF, and 230 OF except SBS which was testedat 180 OF and 230 OF for the same reason as mentioned above.
a. Analysis
Penetration values for control samples AC-20 andAC-10 were 51.4 and 70.1, respectively. Only FCB was used tomodify both AC-20 and AC-10. All other modifiers were blendedwith AC-20. In all cases, when the modifier was mixed with theasphalt cement, the penetration value was reduced. The mostreduction (to a value of 29.4) was associated with the PP, andthe least reduction (to a value of 64.8) was associated with ER.
Reduction in penetration values is also associatedwith the percentage of the additive used and its specificgravity. This information is presented in Table 2.
In examining the results of Table 1, the initialviscosities of the AC-20 and AC-10 were 2443 poise and 1041 poiseat 140 OF, respectively. These values fall within the specifica-tion range. In all cases, when the modifier was mixed with theasphalt cement, the viscosity value of the blend was increased.The greatest increase in viscosity (up to 60,000 poise) wasassociated with the SBS, and the least increase in viscosity (up
34
to 2522 poise) was associated with the ER. The general trendbetween viscosity and penetration data for the various modifiersis normal (i.e., the lower the penetration the higher the viscos-ity, and visa versa). All modified blends exhibited increases inviscosity upon aging in TFOT. The aging factor (AF) and theaging index (AI) were calculated and the results are shown in thelast two columns of Table 1. The results indicate that PP andFCB age faster than the control samples of asphalt cement whilethe ESL, SBS, and ER age more slowly than the control sample.However, the aging index alone is not a valid parameter to definethe aging characteristics of the modifier, because differentmodifiers will result in different initial viscosity values ofthe blends; hence the aging index will include this as anembedded variable. As a better measure of the aging charac-teristics, the following definition is presented:
AAm - ABmIAR = ;where
AAr - ABr
IAR = index of aging rate
ABm,ABr = the before-aging absolute viscosity of themodified and reference blend, respectively
AAm,AAr = the after-aging absolute viscosity of the modifiedand reference blend, respectively.
The IAR will have the advantage of normalizing theviscosity data with respect to the variable initial viscosity, aswell as being a measure of the effect of the modifier on thechange in aging rate.
The aging characteristics using the creep com-pliance data are presented in Section V. The data pertaining tothe aging characteristics are found in Appendix D.
3. Marshall Criteria Results
This test was conducted in accordance with the AirForce specification AFM 88-6. The additive dosage and mixingwith asphalt cement was based on the manufacturer's recommenda-tion. Test results are shown in Appendices C and E. Table 2contains a summary of these results. The last row of Table 2lists the Air Force specifications.
Graphical representations of the stability, optimumbinder content, and specific gravity are presented in Figures 5,6, and 7.
35
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a. Analysis
Table 2 shows that all results meet the Air Forcespecification for Marshall criteria. That implies that theMarshall criteria cannot be used to differentiate 'betweenbituminous mixtures with different types of additives. Further-more, most of the results do not vary greatly as the additivetype changes. Again, this means that the Marshall criteriaparameters, individually or collectively, are not sensitiveenough to detect the mixture variation caused by variations inthe types of additives used. In fact, the measure that we arelooking for is the potential of the mixture to exhibit crackingand/or rutting, compared to conventional asphalt cement mixtures.This measure could not be extracted from the Marshall criteria asall the results meet this standard.
The last column in Table 2 lists the specificgravity of the different modifiers. If the specific gravity isless than that of the asphalt cement, the modifier may float andseparate from the blend. This implies that dispersing of themodifier within the asphalt cement matrix by methods such as highshear mixing is essential. For these modifiers, the agingcharacteristics of the blends are of prime importance.
4. Short-Term Material Characteristics
These tests include the following:
o Modulus of resilience: MR ASTM D-4123
o Indirect tensile strength: cy ASTM D-4123
o Unconfined compressive strength: qu ASTM D-1074
A summary of these results is presented in Table 3.Histograms for comparison of modulus of resilience, indirecttensile strength, and unconfined compressive strength of thevarious mixtures are presented in Figures 8, 9, and 10.
a. Analysis
No standard specification limits are set for thesetests; therefore, comparisons of the above-cited results with theresults of the control samples will be made. All modifiersexcept ESL and ER have increased the modulus of resilience (MR)over that of the control asphaltic mixture. A maximum increaseof 27 percent is associated with EVA, and the least increase ofabout 6 percent is associated with SBS. For all practicalreasons, however, this increase is not considered significant.The same trend is noticed for the indirect tensile strength ay
39
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and unconfined compressive strength qu, except that additivescontributing to the ma:cimum or the least increase are different.
The main conclusions from these results are that thesetests cannot be used to distinguish effects of different types ofmodifiers relative to the control mixtures as the results arecomparable to each other. Because these tests do not reflect themixture performance, they do not indicate whether or not crackingand rutting will be a problem.
5. Long-Term Potentia. Candidacy Tests
These tests include the following:
o C*-Line integral: new procedure
o Compression rutting-creep: modified procedurebased upon the test method presented in VESYS II-Mstructural subsystem manual.
Detailed results of these tests are found in AppendixC. These results are presented in Figure 11 for the C*-lineintegral and Figures C-I through C-9 in Appendix C for thecompression rutting-creep data.
a. Analysis
(1) Cracking Potential
A summary of the results of the C*-lineintegral test is presented in Figure 11. Again, there is nospecification limit for compliance with this test; hence thecontrol mixture (designated AC-20) will be used for comparisonpurposes. Figure 11 is read in terms of the crack speed and theenergy required to generate this crack speed. The more energyrequired and the slower the crack speed the better the mixtureresists cracking. Hence, at 70 OF the FCB, SBS, PP, and ESL arebetter mixtures to resist cracking compared to AC-20, while EVAand ER are not. Hence, one conclusion would be that C*-lineintegral could be appropriate measure for the cracking potentialof asphaltic mixtures with or without modifiers. This test ispart of the proposed screening criteria. The point to beevaluated in a followup study is the temperature-dependence andthe effect of aging on the C*-line integral test results.
(2) Rutting Potential
A summary of the compression creep ruttingtest results at different stress levels is presented in AppendixC.
44
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A nonlinear regression equation was used tofit these data. The mathematical statement of this equationwhich respresents the creep compliance function for the vis-coelastic mechanical Burger model for asphaltic mixtures is:
E(t) -a4tJ(t,ao) = + a2 t + a3 (1 - e
Co
J(t,ao) = creep compliance at stress level ao
6(t) = axial strain as a function of time
ao = the applied constant stress
t = time scale
ai = regression coefficients
Results of the curve fitting are presented inTable 4. The steady-state creep deformation ess is plotted
against the stress levels to enable determination of the yieldpoint of the modified AC mixtures, ay. Results of this step arepresented in Table 5. ay is interpreted as the stress point atwhich plastic deformation will commence; therefore, the higherthe value the better the rutting behavior of the material. Table5 reveals that all modified mixtures are better than the conven-tional AC-20 (or AC-10) to various degrees. The best resultswere with FCB/AC-20 where the yield point almost doubled that ofconventional AC-20. ESL, PP, EVA, and ER exhibited yieldingcharacteristics at the same order of magnitude as conventionalAC-20 mixtures; however, the low yield point does not mean thatthe material will exhibit a high creep deformation rate at higherstress levels. To illustrate this fact, the column labeled"creep rate" in Table 5 should be examined. For example, acomparison of values of PP and EVA, shows that both thesemixtures have equal yield points, although the EVA will exhibitalmost twice the creep deformation as the PP. Accordingly,rutting of AC mixture modified by EVA is expected to be as muchas twice that of AC mixture modified by PP. Another interestingexample is the comparison between FCB/AC-20 and FCB/AC-10mixtures. Both mixtures exhibit equal creep deformation rate;however, the FCB/20 mixture is superior because it also has thehighest yield point value. Further analysis could be made bycomparing the creep data (shown in Appendix C) of the modifiedmixtures to the control AC-20 mix. All modified mixturesexhibited higher creep deformation than AC-20, except PP andFCB/AC-20. In fact, PP was the only mixture that showed lesscreep behavior at all stress levels. FCB/AC-20 showed highercreep values initially, but the values decreased at the end ofthe test period. A comparison of the creep data for any threemixtures, for example PP, SBS and ESL, shows that PP has the
46
TABLE 4. REGRESSION COEFFICIENTS FOR COMPRESSION-RUTTING-CREEPTEST OF MODIFIED ASPHALT CONCRETE.
StressSample Level (psi) a, i 2 a3 a4 ERROR
AC20 15 0.80 .0028 2.21 .053 .01440 1.79 .0098 6.21 .050 .21480 2.90 .0120 11.90 .050 .670160 8.19 .0164 16.80 .0513 3.000
AC10 15 1.06 .0020 2.61 .059 .05340 2.76 .0097 8.3- .050 .50080 5.94 .0120 12.30 .054 1.070
160 13.02 .0123 15.00 .059 3.470
ESL 15 1.27 .0020 3.67 .046 .05940 2.76 .0060 8.69 .052 .31080 6.14 .0060 10.1 .062 1.17
160 11.50 .0090 12.8 .070 1.54
SBS 15 1.32 .0026 3.68 .0537 .07440 4.13 .0069 8.87 .0456 .54080 9.11 .0092 11.70 .0517 1.080
160 15.34 .0100 14.40 .0638 1.700
PP 15 .46 .0014 1.08 .054 .00240 1.13 .0061 3.56 .030 .0780 2.34 .0093 7.39 .032 .16
160 3.86 .0140 12.56 .052 1.04
ER 15 1.45 .0015 2.99 .069 .05540 3.87 .0060 8.09 .050 .34080 6.26 .0076 9.51 .066 .809160 9.65 .0092 12.92 .043 2.07
EVA 15 1.206 .0020 2.46 .043 .07240 3.37 .0040 6.03 .052 .14080 5.00 .0046 7.06 .070 .850160 11.50 .0050 7.23 .043 1.26
FCB/AC-20 15 1.02 .0011 1.87 .058 .0340 2.45 .0033 4.97 .039 .1180 4.89 .0054 8.434 .064 .71
160 10.24 .0080 9.93 .066 1.62
FCB/AC-10 15 2.04 .0020 3.61 .056 .1040 4.57 .0070 9.33 .054 .8080 9.15 .0071 13.03 .056 2.93
160 14.46 .0112 15.36 .066 2.10
47
TABLE 5. YIELD POINT OBTAINED FROM CREEP COMPLIANCE TEST FORMODIFIED MIXTURES
Modified ay, psi Creep Rate I Range2
Mix CR x 10-6
AC-20 26 .0055 .9 - 1.64
AC-10 20 .00029 .35 - 1.22
ESL 28 .0034 .45 - .9
SBS 44 .00095 .89 - 1.0
PP 30 .0058 .65 - 1.4
ER 34 .0021 .66 - .92
EVA 30 .00077 .4 - .5
FCB/AC-20 46 .0031 .43 - .8
FCB/AC-10 25 .003 .59 - 1.0
Ess1 creep rate - micro in/in psi - 1
ao
Ws = variation of the steady state creep deformation
2 range = (highest ss.- lowest Ess) for the evaluated creeprate score. Lowest ess is taken as the value at the yieldpoint.
48
least deformation, followed by ESL and SBS respectively.Comparing these findings to the CR values in Table 5, it could besaid that higher CR values are generally associated with lesscreep behavior. The above discussion shows that the screeningcriteria should account for both parameters in a rutting poten-tial candidacy test, namely, the yield point and the creepdeformation rate. Threshold design values for both of theseparameters could be established as criteria for acceptance/rejec-tion of modifiers to guard against rutting.
(3) Creep Compliance After Aging
The same procedure for obtaining ay and creeprate (CR) cited above was used to obtain these values after agingthe samples in an oven at 140 OF for 7 days. The test resultsare presented in Tables 6 and 7. A summary of the compressioncreep rutting test results at different stress levels is presen-ted in Appendix D. Except for the SBS and FCB/AC-20, ay wasincreased for all modified mixtures; the maximum value of a y wasabout 44 psi. All mixtures exhibited less creep behavior afteraging. In an analysis similar to the one before aging, it can beconcluded that all modified mixtures exhibit better (or slightlybetter) creep behavior than AC-20 after aging. All the modifiedmixtures also exhibited greater values of CR after aging. There-fore, the modifiers could be said to be beneficial for resistingthe aging behavior of asphaltic mixtures.
C. DEVELOPMENT OF PHASE I SCREENING CRITERIA
Test results in this chapter indicate that it is possible todistinguish between the performance characteristics of modifiedasphalt concrete mixtures through employing innovative testingtechniques.
The most important performance characteristics are resis-tance to cracking and to rutting; the C*-line integral is ameasure of the resistance to cracking and the yield point/creepdeformation rate is a measure for resistance to rutting atlaboratory scale. To ensure the compatibility of the modifierwith AC, an index of aging rate cited in this research could beused as a measure for this behavior. However, it should bepointed out that the results, along with the manufacturers'information, indicate that proper mixing and heating are essen-tial to have consistent viscosity results, if consistency is atall possible. The rheological/chemical characterization will becorrelated to viscosity parameters and hence provide the requiredcompatibility acceptance/rejection criteria.
To summarize, the fcllowing screening criteria were proposedin this study:
49
TABLE 6. REGRESSION COEFFICIENTS FOR COMPRESSlON-RUTTING-CREEPTEST OF MODIFIED ASPHALT CONCRETE (AFTER AGING).
StressSample Level (psi) a1 a2 a3 a4 ERROR
AC20 15 0.80 .0033 1.69 .030 1.08140 1.25 .0064 3.40 .032 .04880 2.14 .0113 6.72 .033 .215160 4.79 .0140 12.17 .040 .719
AC10 15 1.054 .0026 3.27 .030 .090740 1.978 .0082 6.48 .033 .233880 3.902 .0125 9.76 .043 .2749160 9.288 .0151 15.01 .043 1.9587
ESL 15 1.00 .0013 1.00 .040 .94940 1.00 .0066 2.745 .050 .06480 2.41 .0116 6.19 .040 .123
160 4.92 .0165 12.86 .050 1.653
SBS 15 .547 .0026 1.89 .042 .002640 1.632 .0081 4.95 .040 .122480 4.039 .0114 9.57 .037 .3380
160 5.879 .0128 12.30 .051 1.1633
PP 15 .305 .0009 .61 .053 .001540 .891 .0031 1.86 .035 .013980 1.972 .0075 3.72 .038 .0866160 3.293 .0138 9.04 .044 .4070
ER 15 .443 .0011 .84 .057 .002840 1.161 .0044 2.22 .038 .025080 2.704 .0086 5.834 .035 .1642160 5.409 .0130 13.84 .030 .9509
EVA 15 1.00 .0009 1.00 .030 .91840 1.00 .0068 2.29 .050 .09180 1.55 .0147 6.50 .050 .245
160 4.67 .0188 15.89 .030 3.451
FCB/AC-20 15 0.80 .0004 1.00 .050 .67240 1.00 .0039 2.29 .050 .11080 1.87 .0072 5.94 .052 .259
160 5.55 .0099 8.48 .070 1.159
FCB/AC-10 15 .623 .0019 1.43 .048 .016940 1.594 .0048 3.64 .049 .037180 3.808 .0078 8.05 .046 .5236160 6.585 .01108 11.85 .063 1.3646
50
TABLE 7. YIELD POINT OBTAINED FROM CREEP COMPLIANCE TEST FORMODIFIED MIXTURES (AFTER AGING).
Modified ay, psi Creep rate 1 Range 2
Mix CR x 10-6
AC-20 28 .0034 .5 - 1.4
AC-10 39 .0031 .57 - 1.5
ESL 38 .0061 .80 - 1.65
SBS 44 .0032 .89 - 1.27
PP 44 .0080 .48 - 1.4
ER 43 .0055 .65 - 1.3
EVA 32 .0051 .49 - 1.9
FCB/AC-20 36 .0034 .33 - 1.0
FCB/AC-10 41 .0036 .67 - 1.1
Ess1 creep rate = micro in/in psi -1
Co
ss = variation of the steady state creep deformation
2 range = (highest ss - lowest Ess) for the evaluated creep
rate score. Lowest tss is taken as the value at the yieldpoint.
51
1. Compatibility:
AAM - ABM
IAR < 1 : IAR =AAR - ABR
where:
IAR = Index of aging rate.
gBM,ABR = The before-aging absolute viscosity ofthe modified and reference blend,respectively.
AAM,AAR = The after-aging absolute viscosity ofthe modified and reference blend,respectively.
The IAR value is obtained from running absoluteviscosity test on the conventional and the modifiedasphalt cements before and after aging. Wheneverpossible, this value should be correlated to rheologi-cal/chemical behavior of the modifier, as suggested inthe Phase II proposal.
2. Optimum mixture design:Currently use Marshall criteria.
Furthermore, the following screening procedures were
developed in this study:
1. Rutting potential:
[ ayield]m > spec.
[ CR ]m < spec.
where:
[Uyield]m = the yield point of the modified mix,psi.
[ CR ]m = creep deformation rate of the modifiedmix, micro in/in psi- I .
Both [yield]m and ( CR ]m are obtained from modified
creep compliance testing.
52
2. Cracking potential:
[C*]m > spec.
[A]m < spec.
where:
[C*]m = the energy line integral value[A]m = the crack speed of the modified mix
Both [C*], and [Aim are obtained from the C*-lineintegral testing.
53
SECTION IV
SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
A. SUMMARY
A literature search for information on modifiers to azphaltconcrete resulted in the identification of more than 300 materi-als for different applications. Those materials were screened toidentify modifiers claimed to be able to solve the rutting andcracking distress of asphalt concrete. In addition, modifierswere classified by type in six groups, namely, polymer,elastomer, fiber, filler, chemical, and miscellaneous. Theliterature, manufacturers' data, and recent studies indicate thatmodifiers belonging to the polymer, elastomer, and filler groupswere the most promising to solve rutting and cracking.
In this phase of study, six different types of modifiers ofthose three groups were selected and analyzed, as well as used todevelop screening crit-ria that are able to distinguish among themodifiers' performance. The screening criteria contain threemajor factors: (1) compatibility and aging, set to ensure thatthe modifier is compatible with the asphalt cement (AC) at theinitial mixing, as well as after aging; (2) potential candidacy,set to ensure that the modified AC mixture will perform in thefield to meet the objectives of minimizing rutting and fatiguecracking distress; and (3) cost prohibition, set to excludemodifiers with ineffective life-cycle cost. The first two areascover the required engineering characteristics of the modified ACmix and are dealt with in this report, while the third areacovers the cost factor and its relation to performance; this areais recommended as a main focus of consideration in a futurestudy. In the Phase I study, a cost limit was set, based uponthe literature review and the researchers' experience. The costlimit was that the selected modifier should not increase the costof the in-place AC mixture by more than 25 percent.
Conventional testing methods including Marshall criteria andcompressive strength, as well as nonconventional testing methodssuch as modulus of resilience and indirect tensile strength, havebeen conducted on the modified asphaltic mixtures and the controlsamples (AC-20 and AC-10). As expected, test results indicatethat the cited conventional and nonconventional testing methodscannot differentiate between characteristics of the modifiedmixtures, and it would be difficult to judge performance; thisproblem led to the development of the study.
Two innovative testing methods with sound theoreticalbackgrounds were used 4.n this study: (1) the C*-line integralmethod to measure the potential for cracking, and (2) themodified compression creep-rutting method to measure the poten-
54
tial for creep and rutting. Test results using these two methodshave shown their potential to distinguish performance of thedifferent modifiers, as related to cracking and rutting.
The greatest advantages of these methods are that theyrelate directly to performance and require simple testingprocedures with no special equipment. The latter may be of primeimportance if these methods are to be adopted in the field asquality control/quality assurance methods.
In effect, the screening criteria developed in Phase Icontain:
1. Compatibility parameter: measured by index of agingrate (IAR).
2. Rutting potential parameters: measured by the yieldpoint ay and creep deformation rate (CR).
3. Cracking potential parameters: measured by the energyline integral [C*] and the crack speed [a].
B. CONCLUSIONS
1. The marketplace is full of modifiers to asphaltconcrete that are claimed to solve rutting and crackingproblems. There is an urgent need to be able to screenout these modifiers and select those appropriate towithstand high-pressure tires, thrust vectoring on theairfield pavement, and temperature blast effects.
2. Conventional test methods such as absolute viscosity,Marshall criteria, and unconfined compressive strength,as well as nonconventional test methods such as theindirect tensile strength and the modulus of resilien-ce, are not able to clearly distinguish the charac-teristics of the asphalt concrete modified by thedifferent types of additives/admixtures.
3. Two innovative testing techniques used in this studycan distinguish between modifiers on the basis of theirperformance. These two methods are:
o C*-line integral
o The yield point and modified creep deformationrate.
Test procedures for these two methods are documented inthis report in Appendix B.
55
C. RECOMMENDATIONS
1. To utilize the screening criteria developed in thisstudy for screening a wider base of modifiers through afactorial design of experiment.
2. To investigate the rheological/chemical characteristicsof the modified blends and correlate these withcompatibility/aging parameters such as IAR.
3. To develop a data base for modifiers that containengineering and cost-effectiveness information.
4. To direct part of a future followup investigationtoward more studies on rheological and chemicalcharacterization of commercially available modifiersfor proper categorization.
56
REFERENCES
1. Askelaud, Donald R., The Science and Engineering of Materia-ls, Brooks/Cole Engineering Division, A Division of Wadswor-th, Inc., 1984.
2. Phillips, David K., Asphalt Additive Workshop, NAPA 31stAnnual Convention, Honolulu, Hawaii, January 18-23, 1986.
3. Winters, W.F., "Baryt;s in Rubber-Asphalt Mixtures,"Proceedings, AAPT, 25, 1956.
4. Thompson, D.C., "Rubber Modifiers," Bituminous Materials,Interscience Publishers, 1964.
5. Thompson, D.C., and Hagman, J.F., "The Modification ofAsphalt with Neoprene," Proc., AAPT, Vol. 27, 1958.
6. Rice, J.J., Field Laboratory Experience with Natural Rubberas an Additive for Asphalt, Asphalt Institute Symposium onRubber in Asphalt, 1960.
7. Gregg, L.E. and Alcoke, W.F., "Investigations of RubberAdditives in Asphalt Paving Mixtures," Proc., AAPT, Vol. 23,1954.
8. Moavenzadeh, F. and Alexander, J.A., Effects of RubberAdditives on Properties of Asphalts, Second Inter-AmericanConf. on Materials Technology, ASME, 1970.
9. Mack, C., "Physical Aspects of Hardening on Paving Asphalt-s," Proc., AAPT, Vol. 27, 1958.
10. Little, D.N., Batton, J.W., White, R.M., Ensley, E.K., Kim,Y., and Ahmed, S.J., Investigation of Asphalt Additives,Texas Transportation Institute, Texas A&M, FHWA/RD-87-001,November 1986.
11. Natural Rubber Bureau, Natural Rubber and You, Washington,D.C., 1951.
12. Gregg, L.E., "Additional Observation on the Use of Rubber inBituminous Paving Mixtures," Technical Bulletin No. 194,American Road Builders Association, pp. 19-30, 1953.
13. LaGrone, B.D., "Rubber Used in Asphalt-Rubber Applications,"Proc., National Seminar on Asphalt-Rubber, FHWA, pp. 241-256, October 1921.
57
14. Oliver, J.W.H., "Research on Asphalt-Rubber at the Austral-ian Road Research Board," Proc., National Seminar onAsphalt-Rubber, FHWA, pp. 241-256, October 1981.
15. Berry, J.P., "Brittle Behavior of Polymeric Solids,"Fracture Processes in Polymeric Solids, IntersciencePublishers, 1964.
16. Benson, J.R., "New Concepts in Rubberized Asphalts," Roadsand Streets, Vol. 28, No. 4, 1955.
17. Cannon, C.R. and Majidzadeh, K., "A Laboratory and FieldStudy on the Use of Elastomers in Hot-Mix EmulsifiedAsphalt," Highway Research Record 404, pp. 33-41, 1972.
18. Pavlovich, R.D., "Asphalt-Rubber, An Overview and SomeObservations," Proc., Pacific Coast User/Producer Con-ference, San Francisco, California, May 1981.
19. Brand, B.G., Scrap Rubber Tire Utilization in Road Dress-inns, U.S. Environmental Protection Agency, Cincinnati,Ohio, March 1974.
20. Majidzadeh, et al., Application of Fracture Mechanics forImproved Design of Bituminous Concrete, Vol. 2, Final ReportNo. FHWA-RD-76-92, 1976.
21. Kelly, A., Strong Solids, Clarendon Press, 1966.
22. McGarry, F.J., Willner, A.M., and Sultan, J.N.,"Relationships Between Resin Fracture and CompositeProperties," AFML-TR-67-381, December 1967.
23. Schuler, Scott, Executive Summary of Asphalt Additives, NewMexico Engineering Research Institute, July 1986.
24. Resource International, Inc., A Preliminary Study ofChemkrete Additives, Final Report, Ohio Department ofTransportation, June 1987.
25. Abdulshafi, A., Rheological Behavior of Rejuvenated AgedAsphalt, MSc. Thesis, OSU, 1981.
26. Majidzadeh, K., et al., Evaluation of Sulfur-Asphalt PavingMixtures in Ohio: A Field and Laboratory Investigation,EES-590, ODOT, 1979.
27. Majidzadeh, K., Abdulshafi, A., and Elaithy, A., Sulphur-Extended Asphalt Mixtures in Ohio, Second Arab RegionalConference on Sulphur and Its Uses in the Arab World,Riyadh, Saudi Arabia, 1985.
58
28. Richey, Barry L. and Little, Dallas, N., "A Sulphlex MixtureDesign Method Based on the Indirect Tensile Test," TRR 911,December 1983.
29. Majidzadeh, K., et al., "Material Chacteristics andPerformance of Bottom Ashes in Bituminous Materiajs," Paperpresented in the TRB Annual Meeting, 1979.
30. Majidzadeh, K., Bokowski, G., and El-Mitiny, R., "MaterialCharacteristics of Power Plant Bottom Ashes and theirPerformance in Bituminous Mixtures: A LaboratoryInvestigation," Proc., Atlanta Ash Conference, 1979.
31. Air Force Civil Engineering Center, Evaluation ofReiuvenators for Bituminous Pavements, Technical Report 76-3, Tyndall Air Force Base, Florida, 1976.
32. Kenis, W.J., Predictive DesiQn Procedure: VESYS UserManual, FHWA-RD-77-154, Final Report, 1978.
33. Moavenzadeh, F., Findakly, H.K., and Sousson, J.E.,Synthesis for Rational Design of Flexible Pavements, FHWAReport 75-29, Washington, D.C., 1975.
34. Beckedahl, H., Gerlach, A., Lucke, H., and Schwaderer, W.,"On Improvements of the Existing VESYS-Concepts," SixthInternational Conference, Structural Design of AsphaltPavements, 1987.
35. Valanis, K.C., "A Theory of Viscoplasticity Without a YieldSurface, Part I: General Theory; Part II: Applications toMechanical Behavior of Metals," Arch. Mech. Stosowanej, No.24, 1971.
36. Zienkiewicz, O.C., Norris, V., and Naylor, D.J., "Plasticityand Viscoplasticity in Soil Mechanics with Special Referenceto Cyclic Loading Problems," Paper presented at theInternational Conference on Finite Elements in NonlinearSolid and Structural Mechanics, Proc., Norway: TapirPublisher, Norway, pp. 455-485, August 1977.
37. Abdulshafi, A. , and Majidzadeh, K.,"Comboviscoelastic/Plastic Modelling and Rutting ofAsphaltic Mixtures," TRR No. 968, December 1984.
38. Abdulshafi, A. and Majidzadeh, K., "J-Integral and CyclicPlasticity Approach to Fatigue and Fracture of AsphalticMixtures," TRR No. 1034, December 1985.
39. Abdulshafi, 0., Rational Material Characterization ofAsphalt Concrete Pavements, Ph.D. Dissertation, The OhioState University, 1983.
59
40. Heislich, Herbert, et al., The6rv and Problems of OrganicChemistry, New York, McGraw-Hill Book Company.
' . Dabin, J., Rapport de Recherche, No. 58/JPD/1958, Publ.Centre de Recherche, Routiers, Bruxelles, Belgium, 1958.
42. Rostler, F.S. and White, R.M., Symposium on Road and PavingMaterials, 1959 ASTM-STP, No. 277, p. 64, 1960.
43. Barth, S.J., Asphalt Science and Technology, Gordon andErenth, London and New York, 1962.
44. Dunning, R.L., and Mendenhall, R.L., Design of RecycledAsphalts and Selection of Modifiers, ASTM, STP 662, 1978.
45. Abdulshafi, A., Viscoelastic/Plastic Characterization,Rutting and Fatiaue of Flexible Pavements, Ph.D.,Dissertation, The Ohio State University, March, 1983.
46. Manson, S.S., "Interfaces Between Fatigue, Creep, andFracture," International Journal of Fracture Mechanics, Vol.1-2, pp. 327-363, 1965-1966.
47. Morrow, Jo Dean, "Cyclic Plastic Strain Energy and Fatigueof Metals," International Friction, Damping and CyclicPlasticity, ASTM-STP378, pp. 45-87, 1965.
48. Weibull, W., Fatigue Testing and Analysis of Results, NewYork, Pergamon Press Ltd., 1960.
49. Landes, J.D. and Begley, J.A., Mechanics of Crack Growth,ASTM, STP 590, pp. 128-148, 1976.
60
APPENDIX A
INVENTORY LIST OF MODIFIERS AND SELECTEDFLASH POINT DATA TO ASPHALT CONCRETE
VH 0 N co 0 q cl q 0 0 q
N,~ IN. N,~ IN N-1 111" Nl l0 co 1,N 0 H% Hl ( - - coH- 0 0 H H 0 0 0 CH 0 0
U) tn V dz 0 4)
WL 4J~ 0-) 40) 4-)O O
4- -)0~ 0 *H) M ~ 0 () 0)0) NWW *-V 0
W4- 0HcIt 0) :3u r -1c . 9:- *HO HO zH r. C: H0 JZ
W 4 %4 () 0 0 HO 0 0 *Oq $4 Q 00U $4Q -H a ~0 9 p0E-i cn 004 u z H z He f<~ z P H P 0 4 OCL
z 10 0 Vo0 9: N 4 4 )
0 0 a0 4-4 0 rq (a
E- 04 ., C 0) 0 V4r-0)U)r 0) 4.)4 4-. 0 OW 0 ) -4CUt: D0 H jr P PH P,4- tPj ~4
0 *H,4 4 0) I41 5-4 MS a) 4) 0) u 0)P~4 V4-X 4- >*vH 41) p 0Qi k *A.,
.,j ., 0A r4 C/) V0 to W0p u4 z H Ma~(~) ra 4.) 1 1 10 4Q) r 0 4 aL~)
IQ a*H j Hr -H.qA 0 U- -H0 r: 41 u4-)V . 41 4 rq uc~ t3P 04E-1 0 0 0 p -4 r. 9z 001
., 10 -- 1 -1-4 r -H *Uc ) 4-V 4.4 ) p 4) 0 -r 00u 0 0 W
P In41i .- 1 V- 4i 41) V- V- 4-1 4 04-) C: V 4)54 0W *-H HHri - 0) H p to Ui to W41 - -A E U ) 05-H 5-at *HV >5- p a t4-) 1 4 a )4- TA (1 9 44 1 Mflj
H 4 r4 I0) V 4 4i0 r. I 40 r.Q 4-)* a) :0 H zp0 i 4r 9W .I-) 04O 04 4) rl (l OWU 4-) -4 V WOMH
o a) cch 4Jt o0 U Mt: WU 0 Mtn SP 4 s O0 -
FZ440 >1 H 0
c 0 Hn UOE- t 0 H- U)
04~. 0 >1 U, U)Hn V) W) W)U, 0 to
4 0 co to v CIDH0 L~4. V- fu V 0N
ri04-) 0 r. r4 Mul0 M 0 EA H r 0 H 4-) 0
0 a0 ) MS 0) 0 H ., fu -H*H 0 zH w 0) r- H-H 4L 5-i 4 -
m .01s 0 Ono 0 0 0 Ica 0w 5-H LO* *Hq r4 H Z*H q .,1- 9 (> z44~- 0 >H V >i 0 P-i4-). *O 4-)z 5-0)1 - >1 r -- Ha)-Hq -H 0) -H t)C 00() -H
H: =$ -5- Xs ~0)4) V 00) 41 r. 0 00)4-V4-) X- v-)-I ( a0) r i MQ)H- E-4 P (d E-4 p (d H Q) 4)p
44 -0 rl 0)4JP4 0 ) N 0Q) N 0 4 -H 0 4-i-H r--H .4-) -Hr0 tN -U 0W r.0 0 4-)US4-) 4-i ().-3 Q) ()~ ri4M-Vr-- -H 0 0 r. p * r p5~S 5a r.fl 0C4H p.4Wfr.(0 -4 - -- *to 4j Z 4; 4 0 IV ) -H 0 (o0) -H (0 *jH W-
w~~~~c U)mmC) U( uu3
V U) : 0 0 0010 00 0 0 H H
0 0i 0 0 E-0CVN N H H UN
pc U) WE-1 C/) 0 0
62
CD CD CD CD co co 00 co 03IN IN. N1 NN N N1- N1HM 0 0 0 0 0
S 4-) t4- 4) -
z - Q) it >)t > > WV00 0 R-~ H~ tp "A * ) r-i0 a) tU :. lz 0 -0r 1r > 9 > r 04-) -4(a 0)0r 4-d r.H .9-4 = - U9H 9)- r U"-
P 4-~4 0 0 F-f HO 1%4 W 0) ) W ) r)0 Hw 2~ Hz 0 13 H~ OO4 0 a4 04 A4 A 4 4U 0 V)4.z 4-) 4-4- H- -'-4o H 0)H (0 4) V.U 0 ~ t Vo I0 fu4 to p~ 0 w-4) 4J~ 0l) 41) 4 04 -0t0H- m0 04 *d' 4- 0 (d 0.. to H w 4-)4) 0)0 OWd -'-44.0 th . 440 0) p4s-h U> >1 5..~*>W 4~ C M r 3U 4-) 0 01)"i V~.4 4-) 4-4J 4) mo V. 0) 0 )
CL V -1 U44 4) (nW$4 9 H- r- 0- ~ 044 4 4r-)~ -- H0 PH~ -440 0 )to 0) 01.0 U V4-)'~ 1V 0 *-4 4-) *H/0 -'-4 0~~HtColo .0 4> .0 I4X M 4) U 4-4 4-) >to p0 to
404- 4 u V to 0* Hr r4 w .,4 0 a0)0 u j 9H4-) .4 t4-) ~ >i- W 0 . .O0 V EO >i tH f> ~4-) 0 0 W -4U th-r HHI 4-) > -11r4 V W W)(n 4-4 049.443 O >1Vl COJ(W-).1 0.0Q0) 0 0 -H-44V 0 0) >1 0 0 N P4413 MWH 5-4o 4 tn cH ro V4-~4 W44 V-) -H 0)~ r. w 0 0H 04 (v -H 0.4-v10 (~od - y H 0) a) 4) 0 >1 VH- to $4H ) OciW 0 H 0 05~o- W C-i. 0) W H 4wufi0r >10En 0p I () w~ Vl "o ~2>,H H- 4.)r: OfOf( .et4-) (UX Hq>0)99:30S 0 P90 Y tO U4J 0 0 t0 w0.- 0 0-I ,
0
a) * -ci-0 N 0 H7 M0 t4-i CoJ
tof 04 H4 046 0 0)0 0)'.q nH 4-i kO *- U 0 it v4 ), r0> wW 0 0iUW .0 0~ OV o 40Z (HU) 4 0)4
W.Hr -r fu Ht' Wo 0 -i :aH4 V 0 a) z >1 f 4.04 a) 41 r
1.V -4 4-V5. ta to *H 0-) c U) z -)0* 4- 0) r t 0)r.(0 00X r-I Q0) - *-14-) .4 H U). j.V0 p 0 Po 4 w 0 04I 4-) Q)0 : 0 ) 1 rz,~ w. u- WU(a UU) 0(0) 0 x m 0 1 -U 0 >it Htor-im~44I1 0 1 0 C-) 0- fu 44 do ) x 0) r Z-H
r: O H r ~0Hr r- HH .4-) > 0 -0) 0 zQ) 0CD r a)ODC: 4-00 oN raV 510 0 P > p S-i4 H w 0) .H w -40 *- - 0 %0-- 0 0 p I Nr co W H4-H
NE- E- U) > -
430 E-4 04u L) 4 r E U) ( 0II NW ( N I <
zIH4 - I %DH E-I0 - t n 3:1Zl co
040 =F4I too 0 > HU ow Uw rL4
63
H .c 0) H0 0 0 0
OD r- CC) 00C)c Dm0 0 0 0 H 0 0 0 Hl 0
E-q 4 >) U) >
z H0I (3) H~ tp fo p r H C qZ
4-)W-- Cfl- r-H W-'- 5:-ftHr$ C/I-H -H .j i
4J ) 0) c 0 HO4 a)) H ) 0 0) aO) 0) 0) r.C) '-C)H Co H z 044 40 H~ a4 H4 P4 a4
0) -q 4..)o X -iCl H--'- 0 0) x ri
u .o 10.rq -Hr W-I10Wl 4J .14 4- C/ 0 44W m/~ *Hq- 0)4) En 4 -P x -P U) x
r.0 0 0 0 W 00 rq -11 0Xo ro 0) 04 Im a) to 11
U) (1) >4-)E-f U 0 U)I X 0 H-o 4 0) 4 0) 0 44 40) U~ H > 1 S-< r:0 )x r-=0) ) 9 - > fu H -H 410 p- CH- *-4~ rH *r . > > -HA *Hj H-j L -,4-4 >4 :341 -r-4 0 '0 la Q0 0 -H 0) C/ 41 Co H-i 4-) -V) P r34U 0) V 0 V 4 4-) 4 ( 4) 4 -) H-i4- , 04 ::rtoHU 0)Q) (v 00r:) p (d p o m p m rjCO .,q ) r,(J)uHZ0) '0 .0 4 >-t ) H--4 04 ) .Q Q) 4 U40Q
4-)~ r-:W 0QQ H' 000 (1 -Q4 t (30 - to C4ED 4t Q)H1 r 0 ) 4 04 4 4 0 1 0 ) P 4 H C O H - 4 (n0 U E-~i 40
r24 c/)0 U 0>HH
H- CC) 0) to p NCoq a% (a Hl 0) O ODZ'0 mH cco 0
fom H 4- (n04 0o -H 04) (UH I -t0 Co Lo ( 40) 44 N 0 r)*:0 - H H WCp a4)~ w % o o r
> P r4 0 H - 04 H ~ ~ ' 001 0) 0.z ) m)H 0)C 0 0-H 41 pH0 M s 1
H- xH 04 0 00P M 9 J .0*iUt 0 0 r.00 0) -3-i-10 HO 0~o Q) p0p r Z~- () U-H 0ro~ 1%0 1 444 ZJl. 9: -U -H0 4-)0) P - 1: 1 0 t' 0 0 0 H S.IH 0 OHI 1) 00 fH -q :%r- 40 4 r-q a) 9 ,Q ' 0 4 Wzam 0)i D H0M 'j0 -- jHrn rq (1*- H 0) -H r= IaMco-H r .g -o 0) (OCEn m1a
:E tP 4>0 C m uc 4r n< a
H 04rZ-. x
V 0 1 0 U H H HL) U 0 00 I Z
0 M Ho > >4 U 14N aH4 H oH 0 0 0 >P4~ ry Zx f4 rz z 0
64
0 en co 0 HNz n H- 0 0 0 0 H- 0 HH 0H 0
E- 4-)z (a()o 41 4.)
go a)~ NO() NO WNa) *,q (1) I00 god 'o - ljtr IH *H *Hq *'"-4Cq) HO4 0 H9 p.-i 4 r-40 H rU V 9 4O) p-i u O p-4 HO p*HOfu ,) ~) HO 4)U 0 ) HU
z Uf)0P4 l<' l< o f<4 04 004 O HZ 04 00u 4-)
H- E)0 n .QE- 0 >- 0 p
x0 *rq 4-) :r-4- 4) 44V in U0\1 in 4-) 4.) 4J 43 0 , * )
U) Lcl ~ Q) a) 0 4) '0 inr-i4.)tn 4) 4-)40 ) 4$444o 'dZQ m o .i 4P 9:. 4-) t7p U) V ( 0) -H 04) =k4
Ht-q: n ri 99 . .,-44C in Z 44'0 0Uf) *H 0 t- .14 4-J4 " ~ 0 '-I rq = uZ 404 90O -H n CAr.rx 4-) (w 0p t O -H- 04 04 04 4-4 1040 10 H- S:i x toH .-- O)~ in .-q4- 0 0 *H 0) k-4It 4)H '00FZ4- 4) 4) 9c -kHO ~4)V N 04. 9 z0 0H 1 tIt k- 4-) 4-) 4) 04 tv -r4 ) 0
10 : - V'~H 4 p- E0 Uj 4)-Hq 4)>iO U k V il U O4-). HH0 ~4H r- 0 ) 1 1 44)i H -E-4 -4 0) r 4)4 ( 0 t n0 (a() C04 9 n ) IQ *r4 rq 4J -4q0 it H- .0 W >1 =: H) W4cl (a: F 4.) 4-) 9: ax ,>1 04 0 0 F-414 a 4X 4
0) 0I 0 ti 4Z 4o44 C U U44 r
'-0 0
0 0 * t *LC) W) 0) ty U in ODLO LO 04 Hi 0H .Q I wpt)a0 co coa p )- pN IQ 10 *HO 0 0c H D -E- 0 in 0' LO 0 oo 0 0*'-ao 1
w tu 44 ON 0)U ~ H 0U)%z~~'44~ 0) 0 0oW4 ( )H-
H l CN N 4) 0 410 0) 0) .4 a) a)m0 4m0H-0 kH k) in -H 0 i 0 (L) (4 0 4 M .5- 5-r (d -H. -4HO E4 r -HV =n 43 (0 9 19
4) 0 Q~) 4J 0 V 4 00) ~0 0 O r-0 Oi0U 0:$ IN k- Hs NI-4! ~-to P0 540 tn t 04) 4 00 P- -0u o x X r-H4-3 H0 aq r. tvf 00NM 4 ls 1 r4-40 C-- 0 1 0 to 0~ 09- 4-H -, 4)~ 1/) > - - 0d ) r. piNit f
0 j 4 - W 44 0 0 4)V 00 '0 0 '0 0 H V) P- c UAO >1 4-)04 'oP : k.0 X C0). -r4 r-H 0.9 0 1!4 HO() -H 0) .qH Oto0 0 aH- U044 U0 N - r E-4 HO IUC~ '00 04 4 c mcn P4 P40u
0
N4 HV N E-
x x z z W 144)WW 0 0 >l > E4 HE-
0 04 04 H E04~ E/ t :I1IxW 0 C' M >4 Wl >4 w >4' %o
H H fn12 s0 ~H >44 > OH O H 0 w
a4 0 0 04 04 N4 04 N4 N 4r 4 la f, 04
65
o1 H
Z 0." 4-) (0E-i rq0Z 4-) 41-)
> > 0UH)0U -
(t)- -H1 0 ~ 0~ r. :
E-4 4-. 0 (U r.O 00 0HH ) -- 40) E 0 V~
at4- 0qa -
0- a)4' 4J 0 U~-U) ~ ~ 4- 00 L - X 4- 5
0-H Z ~ 0H4) 0 H)O5~ - Oq 4 J 4C04. -Hq HH
aj4 0W 3-i -H ) c:4- >-H 4-i 04 E-1 44J ' 0 ~0 r- Z- OH 0 ': 4- J' C )C- x- -H $4 '4-4c0 U a 0 034U) 4.3 0~ 0 4H-4~'
44a 0 rq 0 340 N0 0 24 a I'0 f .q d-'-4 4-i -- HHW t 4) 1-W V c 9
H$ ~ 0 p -0 '~ O 0 4 -ri0
0) 4- ( 1r V01 z r4 4 pqt 0 z c
m- ()M Z4 0 4 (
0-3 r
p ~~ H (n 34J 0 4)
w -, fHq D 40 r:H -)(1>-4 :4 z U .-lc F s 0 :40Erz 4 a) 1 -3. a) p- 9n .C4. 0W ON _ 0 > EQ) ~>L 4 4-) .(154- V0 4)M U4 00~ HO-11 0c4 H' M- '-4 1 -14
:I o~ Eq 0 1)c 94)xt 0 ) X'- i
LO/2A 4-) z~ LO 4. O ) 0Lo0 >iN ' LOV > 04) 1 t4MV() 0-
(o0 co 4 0~ N 0)(N-q -r 0I 0 0 HC -P 44~~ P 4X P) a24 zu co H t
66)
CD co co
In 0 0 H-
U 4-).9-
'* * >1 9 0
E-4 (0 In *- .0 a4
o 1-4
Z 0 0d
40
o 4.) 4O 0H ~~4-44) -4.
0. S0. .o pn
00
Q 000c >-I -) 0 J0
4- U)
00
U) WIQC 0 0%
0 Wo 0z O>r4~ 0 S4W p p o E-4H
4 4-4r Z4~ 0 *dI-.
4-i H- : r
r.D x x HA4 l w ocn 04)67
TABLE A-2. FLASH POINTS DATA FOR SELECTED MODIFIERS AS PROVIDEDBY THE MANUFACTURER.
MODIFIER TYPE FLASH POINT INFORMATION
ESL N/A - Material safety data sheet(MSDS) rating zero for fire hazard.Non-flammable unless all of wateris evaporated and the dry polymeris heated substantially over 350 OFfor extended time or exposed toopen ignition source.
SBS 400 - 450 OF (electrostatic buildup
to be avoided).
PP 450 OF
ER N/A - (Flash ignition temperature500 OF).
EVA 430 OF - (Anti-ignition 480 OF).
FCB 600 OF (500 OF oil used in productonly -6%).
AC-20 450 OFAC-10 450 OF
68
APPENDIX B
TEST METHODS AND PROCEDURES
69
APPENDIX B
TEST METHODS AND PROCEDURES
A. The CVP Method
This test is an extension to the creep-rutting test citedunder the incremental static-dynamic series of the VESYS II MUser's Manual (Reference 32). The modification to this test isin Step 4 of static-creep portion as follows:
4. Incremental Static Loading:
(a) Apply one ramp load of 20 psi to the specimen asquickly as possible and hold load for 0.1 second.Release the load and measure total permanentdeformation after two minutes of unload. SeeFigure B-i for a description of the loadingfunction. If the deformation under load starts toexceed 2500 micro-units of strain, immediatelyreduce the maximum stress level by 5 psi. If thedeformation starts to exceed 2500 microunitstrain, then reduce the stress level by another 5psi. Wait 30 minutes and repeat Step 4(a) at thislevel.
(b) Apply a second ramp load to the specimen at thesame stress level used above and hold for 1second. Release the load and measure the totalpermanent deformation after 2 minutes of unload.
(c) Apply a third ramp load to the specimen at thelevel used in 4(a) and hold for 10 seconds.Release the load and measure the permanentdeformation after 2 minutes of unload or whenrebound becomes negligible.
(d) Apply a fourth ramp load to the specimen at thelevel used in 4(a) above and hold for 100 seconds.Release the load and measure the total permanentdeformation remaining after four minutes of unloador when rebound becomes negligible.
(e) Apply a fifth ramp load to the specimen at thelevel used in 4(a) above and hold for 1000seconds. Measure the magnitude of the creepdeformation during loading after 0.03, 0.1, 1.0,3.0, 10.0, 30.0, 100.0 and 1000.0 seconds.Release the load and measure the total permanentdeformation after eight minutes of unload or whenrebound becomes negligible.
70
EE
T
U))
Q))
4J 4.) 04.) a) 1
.1 s4 In 1.-4 4.) 4-)
04.) (1 0 C
(10a) 4
a)i 4.)
'-I
1.0LAQLA ~ -C64.
U,4
o o g0E
?9 'a
II 71
5. Apply a sixth ramp load to the specimen at a levelequal to 0.5 a obtained from the indirect tensile testand hold for I000 seconds. Measure the magnitude ofcreep deformation, release the load, and measure thepermanent deformation as in Step 4(e) above.
6. Apply a seventh ramp load to the specimen at a levelequal to 1.5 times that of Step 5 above and hold for1000 seconds. Measure the magnitude of creep deforma-tion, release the load, and measure the permanentdeformation as in Step 4(e) above.NOTE: Loading and response simulations are shown in
Figure B-1.
B. THE C*-LINE INTEGRAL TEST
This test procedure follows the method described below(Reference 33). However, the sample preparation and testing isidentical to the method developed by the Dr. Abdulshafi for theJ-integral; the only difference is the requirement to measureboth the load, displacement, and time simultaneously, while theJ-integral is required to measure the load and displacementsimultaneously. The C*-line integral test procedure is asfollows:
1. Assumptions
o Crack tip stress-strain singularity for large-scale yielding exists.
o Two-dimensional space (or less) problems onlyshould be considered; mainly plane strain problemsare considered.
o Deformation theory of plasticity is assumed; i.e.,unloading is not permitted.
2. Specimens
A Marshall-type specimen is used. This is a cylindri-cal disk with a 4-inch diameter and a 2.5-inch thickness. Thesedimensions are compatible with the requirement of plane straincondition to be achieved. Field- extracted cores could also beprocessed to have the same dimensions; however, a minimumthickness of 2 inches should not be violated.
A right-angled wedge is cut into the disc specimen toaccommodate the loading device. The wedge should be cut to adepth of 0.75 inch along the specimen diameter and extended overthe whole thickness, as shown in Figure 3. Care should beexercised to ensure symmetry of the wedge about the vertical axis
72
and smoothness of cut surfaces for proper contact with theloading steel wedges. A very small, artificially made crackshould be sawed at the tip of the wedge (notch) to channelizecrack initiation. It is preferable that the vertical strip thatincludes the notch tip be painted a lighter color to clearlydistinguish crack initiation and propagation processes. Avertical line extending from the notch tip to the contact pointof the seating rod should be marked and scaled. It is preferableto paint the two faces of the specimens along the vertical linewith light color paint.
A gradually and slowly increasing monotonic load isapplied to the sample until a crack is noticed. The load shouldbe maintained until the required crack size is reached. Identi-cal samples with different crack sizes should be made as above.
3. Experimental Setup
The experimental setup is similar to the indirecttensile strength test method, ASTM D-4123. The sample is seatedon a steel bar of 1-inch-by-i-inch cross-section and 2.5-inchlength. The steel bar face in contact with the specimen shouldhave a circular groove along the whole length with such adiameter as to assure proper contact with the specimen. Thesteel bar should be placed over the testing machine base plate.The notched part of the specimen should be pointing towards theloading head of the testing machine. Two steel plate wedgesmatching the notch surfaces are placed in their respectivepositions while a semicircular piece of road of sufficient lengthand rigidity is used to transmit the vertical load to the platewedges. The dimensions of the wedge, plates, and semicircularrod are such that symmetry of loading is maintained about thevertical axis. Alignment of the sample is such that the tip ofthe wedge is exactly lined up with the point of the contart withthe seating rod and is also lined up with the applied load. Thisalignment is of great importance and will affect test results ifnot achieved.
4. Test Procedure
a. Set up the sample to have proper alignment.
b. Bring the machine loading head into contact withthe loading device and apply a slow ramp loadingand observe the crack developed to reach therequired size, at which point Loading should bereleased. The crack size should then be measuredaccurately.
c. The test procedure from this point on is identicalto the indirect tensile test with the followingmodification:
73
(1) Apply a load at constant stroke rate.
(2) Monitor and record the load and crack lengthat 0.2-inch intervals until failure.
(3) Repeat steps (1) and (2) on a new specimenwith different stroke rate.
(4) At least three stroke rates should be chosenand three specimens for each stroke ratetested.
C. INTERPRETATION OF TEST RESULTS
This section outlines how interpretation of test resultswill be made. Actual interpretation will be given in the finalrepo-ct.
1. Aging Index
IAR 5 1
2. The CVP Testing
[ayield)m > [ayield~r
[CR~m < (CR~r
where:
ayield = The yield point of the mix; i.e., the strezsat which plastic deformation commences.
m, r = Refer to modified and reference mixture,respectively.
(CR]m = The creep deformation rate of the modifiedmixture, micro in/in psi.
3. The C*-Line Integral
[C* m > [C*] r
[a]m < [air for the same C*
where:
CC*] = The energy release rate line integral crtime-dependent material
[a] = The crack growth ratem,r As previously defined
74
APPENDIX C
PHASE I TEST RESULTS
75
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08
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .01 IN./MIN.).
CrackLength, in. .4 .8 1.2 1.6 2.0 2.4 2.8
Modifer (1 Cm) (2 Cm) (3 Cm) (4 Cm) (5 Cm) (6 Cm) (7 Cm)
AC-10 Time, 4.09 4.30 4.48 5.40#1 Min.
Load, 200 150 125 75Lbs.
AC-10 Time, 2.34 2.42 2.57 3.06 3.55 5.12 5.58
#2 Min.
Load, 450 375 250 187 62 25 12Lbs.
AC-10 Time, 3.16 3.28#3 Min.
Load, 225 125Lbs.
AC-20 Time, 2.59 3.07 3.15 3.28 3.47 5.10#1 Min.
Load, 650 575 350 125 100 0Lbs.
AC-20 Time, 3.30 1.36 3.47 3.52 3.58 4.50 8.03#2 Min.
Load, 688 650 620 588 525 212 20Lbs.
AC-20 Time, 3.28 3.33 3.41 3.47 4.03 5.18 9.00
#3 Min.
Load, 750 725 675 600 475 88 25
Lbs.
FCB/ Time, -2.39 2.99 2.52 2.58 3.50 5.35 7.07AC-10 Min.#1
Load, 750 625 250 250 75 50 20Lbs.
FCB/ Time, 2.22 2.30 2.40 2.52 3.20 3.59AC-10 Min.#2
Load, 575 450 350 275 175 112Lbs.
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .01 IN./MIN.), (CONTINUED).
FCB/ Time, 2.10 2.15 2.28 2.48 3.12 3.34 3.50AC-10 Min.#3
Load, 838 700 550 275 125 100 62Lbs.
PP* Time, 3.30 3.40 3.58 4.58 6.02 7.48 13.40#1 Min.
Load, 325 300 175 75 62 25 0Lbs.
PP* Time, 2.55 3.07 3.19 3.40
#2 Min.
Load, 700 450 200 75Lbs.
PP* Time, 3.04 3.10 3.20 3.32 3.59 4.09 6.05#3 Min.
Load, 712 625 550 412 262 225 100Lbs.
ESL Time, 3.07 3.21 3.43 4.02 4.43 5.45 8.40#i Min.
Load, 875 900 625 450 250 175 25Lbs.
ESL Time, 4.03 4.10 4.18 4.33 4.52 6.09#2 Min.
Load, 875 700 500 350 225 75Lbs.
FCB/ Time, 2.58 3.20 3.40 3.51 4.03 6.45 8.37AC-20 Min.#1
Load, 1200 900 325 300 275 75 25Lbs.
FCB/ Time, 2.22 2.30 2.40 2.52 3.20 3.59AC-20 Min.#2
Load, 575 450 350 275 175 112Lbs.
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .01 IN./MIN.), (CONTINUED).
SBS Time, 2.20 2.56 3.06 3.14 3.52 5.30 6.50#1 Min.
Load, 950 225 175 150 100 50 0Lbs.
SBS Time, 4.11 4.19 4.35 4.52 5.21 5.38 6.59#2 Min.
Load, 725 725 700 600 300 200 50Lbs.
SBS Time, 3.09 3.17 3.34 3.45#3 Min.
Load, 600 425 262 188Lbs.
EVA Time, 2.35 2.44 2.54 3.13 3.24 3.35 5.21#i Min.
Load, 825 850 850 800 525 500 125Lbs.
EVA Time, 2.34 2.38 2.45 3.07 3.18 3.39 4.05#2 Min.
Load, 750 725 575 175 100 60 40Lbs.
ER Time, 2.20 2.27 2.37 2.50 3.15 4.10 8.04#i Min.
Load, 525 450 425 325 200 125 0Lbs.
ER Time, 2.09 2.13 2.19 2.28 2.39 3.04 3.49#2 Min.
Load, 825 825 825 750 575 250 50Lbs.
ER Time, 2.31 2.42 2.54 3.08 3.52 5.08#3 Min.
Load, 700 700 650 575 275 125Lbs.
83
TABLE C-2. C* - LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .013 IN./MIN.).
CrackLength, in. .4 .8 1.2 1.6 2.0 2.4 2.8
Modifer (1 Cm) (2 Cm) (3 Cm) (4 Cm) (5 Cm) (6 Cm) (7 Cm)
AC-10 Time, 5.45 6.04 6.34 6.54 7.14 8.59 13.35#1 Min.
Load, 575 400 225 125 125 75 0Lbs.
AC-10 Time, 4.41 5.00 5.14 5.37 6.09 8.01#2 Min.
Load, 312 262 225 187 137 37Lbs.
AC-10 Time, 5.13 5.27 5.50 6.08 7.04 9.02#3 Min.
Load, 200 175 125 120 87 12Lbs.
AC-20 Time, 4.25 4.42 5.04 6.00 7.05 8.18 13.39#1 Min.
Load, 575 525 500 300 175 112 25Lbs.
AC-20 Time, 4.28 4.42 4.52 5.58 7.02#2 Min.
Load, 700 725 700 550 200Lbs.
AC-20 Time, 4.55 5.35 6.42 7.40 8.00 8.35 13.20#3 Min.
Load, 700 625 288 150 125 100 25Lbs.
FCB/ Time, 3.35 4.53 5.20 5.54 7.24 8.46AC-10 Min.#1
Load, 600 175 150 100 50 25Lbs.
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .013 IN./MIN.), (CONTINUED).
FCB/ Time 4.47 5.15 5.44 6.22 7.11 9.30AC-10 Min.#2
Load, 625 525 350 250 112 37Lbs.
FCB/ Time, 2.44 2.55 3.06 3.15 3.51 4.34 5.54AC-10 Min.#3
Load, 400 375 350 275 150 88 12Lbs.
PP* Time, 5.55 6.11 6.28 6.45 7.35 8.54#i Min.
Load, 900 900 800 525 250 0Lbs.
PP* Time, 4.55 5.07 5.19 5.33 6.15 8.36#2 Min.
Load, 625 375 300 225 137 12Lbs.
PP* Time, 3.04 3.18 3.35 4.00 4.22 6.33 10.25#3 Min.
Load, 425 412 388 300 275 75 25Lbs.
ESL Time, 5.00 5.12 5.33 8.04 9.08 14.20#i Min.
Load, 1000 975 875 625 225 162 25Lbs.
ESL Time, 4.08 4.17 4.36 4.49 6.03 6.58 7.36#2 Min.
Load, 1100 1075 950 500 188 125 100Lbs.
ESL Time, 4.14 4.26 4.45 5.25 6.43 7.03#3 Min.
Load, 8/5 8,15 850 750 250 200Lbs.
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .013 IN./MIN.), (CONTINUED).
FCB/ Time, 4.02 4.17 4.38 5.21 6.11 6.50 7.12AC-20 Min.#1
Load, 950 975 950 750 375 225 200lbs.
FCB/ Time, 4.16 4.30 5.04 5.30 5.55 6.58 8.04AC-20 Min.#2
Load, 925 925 875 575 375 225 112lbs.
FCB/ Time, 4.28 4.36 5.25 6.04 6.28 7.30 8.20AC-20 Min.#3
Load, 800 800 650 475 338 175 100Min.
SBS Time, 4.20 4.36 4.59 5.22 6.39 7.40 9.03#1 Min.
Load, 1050 1075 900 300 125 75 50lbs.
SBS Time, 4.17 4.32 4.51 5.19 6.46 7.25 9.05#2 Min.
Load, 850 750 425 188 88 60 20lbs.
SBS Time, 4.22 4.37 4.44 4.55 5.26 6.33 7.55#3 Min.
Load, 725 500 325 260 175 100 25
lbs.
EVA Time, 4.54 5.09 5.36 5.55 6.20 8.40 10.22#1 Min.
Load, 625 600 550 350 225 100 62lbs.
EVA Time, 4.02 4.16 4.27 4.50 5.16 6.03' 7.30t#2 Min.
Load, 700 650 600 250 110 62 12lbs.
86
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .013 IN./MIN.), (CONTINUED).
EVA Time, 3.57 4.15 4.29 4.40 4.52 5.30 7.28#3 Min.
Load, 750 725 550 500 350 200 25lbs.
ER Time, 4.28 4.42 5.17 5.54 7.02#1 Min.
Load, 525 500 450 250 0lbs.
ER Time, 3.40 3.55 4.56 6.36 7.10 7.58 8.30#2 Min.
Load, 662 660 462 137 75 50 12lbs.
ER 1lime, 4.06 4.30 5.23 6.07 7.27 8.45#3 Min.
Load, 450 350 225 175 75 12lbs.
TABLE C-2. C* - LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .019 IN./MIN.).
CrackLength, in. .4 .8 1.2 1.6 2.0 2.4 2.8
MODIFER (1 cm) (2 cm) (3 cm) (4 cm) (5 cm) (6 cm) (7 cm)
AC-10 Time, 7.00 7.09 7.22 7.37 7.53 9.40 10.50#1 Min.
Load, 300 300 225 200 125 75 50lbs.
AC-10 Time, 4.40 5.08 5.39 6.45 7.32 8.29#2 Min.
Load, 300 262 250 200 150 625lbs.
AC-10 Time, 5.57 6.12 6.38 8.18 7.18 9.03 11.09#3 Min.
Load, 375 350 275 100 75 37lbs.
AC-20 Time, 5.07 5.17 6.03 6.43 7.03 7.47 10.43#i Min.
Load, 550 525 375 240 200 150 62lbs.
AC-20 Time, 6.00 6.15 6.41 7.10 7.58 8.40 10.02#2 Min.
Load, 850 875 825 575 225 100 50lbs.
AC-20 Time, 5.57 6.04 6.14 6.54 7.42 9.22 10.36#3 Min.
Load, 375 350 325 200 125 62 25lbs.
FCB/ Time, 6.38 7.02 7.53 8.44 9.22AC-10 Min.#1
Load, 375 275 200 125 100lbs.
FCB/ Time, 4.40 4.56 5.20 5.55 6.40 8.30 10.12AC-10 Min.#2
Load, 600 450 325 188 125 75 50lbs.
88
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .019 IN./MIN.), (CONTINUED).
FCB/ Time, 5.50 5.25 5.51 6.25 6.34 6.25 6.10AC-10 Min.#3
Load, 788 750 700 300 225 300lbs.
PP* Time, 9.02 9.18 9.3? 10.01 11.27 12.30 12.40#1 Min.
Load, 650 625 575 525 225 150 125lbs.
PP* Time, 5.34 6.40 7.58 8.30 9.20 10.30 12.40#2 Min.
Load, 725 600 225 150 100 50lbs.
PP* Time, 5.42 5.52 6.28 6.46 7.26 8.40 13.58#3 Min.
Load, 650 600 375 275 188 125 25lbs.
ESL Time, 6.56 7.08 7.20 7.42 8.45 10.09 14.52#1 Min.
Load, 900 875 850 825 600 350 125lbs.
ESL Time, 6.29 6.42 7.05 8.16 9.29 11.22#2 Min.
Load, 700 588 450 150 100 75lbs.
ESL Time, 6.06 6.23 6.39 6.58 7.24 10.38 13.59#3 Min.
Load, 575 525 475 425 350 150 25lbs.
89
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .019 IN./MIN.), (CONTINUED).
FCB/ Time, 5.26 6.21 6.32 6.42 6.56 7.28 14.39AC-20 Min.#1
Load, 650 375 350 340 275 225 75Lbs.
FCB/ Time, 4.40 5.02 5.30 6.04 6.44 8.09 11.04AC-20 Min.
#2
Load, 725 700 562 350 200 75 12Lbs.
FCB/ Time, 4.17 4.47 5.20 5.56 6.46 7.44 9.52AC-20 Min.#3
Load, 788 712 588 300 162 88 25Min.
SBS Time, 5.32 6.03 6.20 6.30 8.32 9.43 10.50#1 Min.
Load, 825 775 625 550 150 125 100Lbs.
SBS Time, 6.39 6.45 6.57 7.18 7.59 8.53 12.14#2 Min.
Load, 625 600 500 400 150 112 12Lbs.
SBS Time, 6.28 6.35 6.50 7.20 8.04 9.06#3 Min.
Load, 725 700 638 425 238 138Lbs.
EVA Time, 6.30 6.42 6.58 7.11 7.57 9.07 9.15#1 Min.
Load, 475 450 375 350 150 100 80Lbs.
EVA Time, 6.13 6.32 6.50 7.08 7.36 8.14 9.04#2 Min.
Load, 575 312 175 138 100 75 25Lbs.
90
TABLE C-2. C*-LINE INTEGRAL TEST RESULTS,(DISPLACEMENT RATE .019 IN./MIN.), (CONCLUDED).
EVA Time, 5.37 5.51 6.12 6.38 7.07 8.03 8.59
#3 Min.
Load, 600 575 500 400 250 150 100Lbs.
ER Time, 5.21 5.36 5.44 6.01 6.26 9.29#1 Min.
Load, 450 400 350 330 200 25Lbs.
ER Time, 6.42 6.50 7.02 7.20 8.16 9.37#2 Min.
Load, 500 475 400 275 125 37Lbs.
ER Time, 7.07 7.14 7.22 7.42 8.41 10.20 11.44#3 Min.
Load, 512 450 412 338 188 112 75Lbs.
91
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Figure C-10. Marshall Mix Design Curves for AC-20.
103
2. MARSHALL MIX DESIGN DATA FOR AC-10
104
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*! C! 9l 9 9 9 9 9 o! 9
H'OIr.CMC1 D0 %0)O U)U). OHi c,4 Lnc Vt 0 O
* t- O999 Ce) ... C:) .%o L o c :) ... Cx) w a Cu!u*!u !u u!w~ U))U u-)U 'in' LnD' LnL n% n .n.
HNCD (D t n eC) rqU Lnc' w ( H' ) N
105
4500
00
15--- --
2500
1500 LL L4.5 5.0. 5.5 6.0 6.5. 7.0 4.5 5.0 5.5 6.0 6. 70
% AC by Wt of Mix % ACby Wtof Mix
10148 ---
8 a 147
44
445 5 . 5 .5 6 .0 6 .5 7 .
% AC by Wt of Mix I A'. by Wt of Mix
Figure C-11. Marshall Mix Design Curves for AC-10.
106
3. MARSHALL MIX DESIGN DATA FOR ESL
107
0n 0l D N 0 rI % 11% IV en a
t-4 ,-I rl-4 u-A rq H4 i r i w
I-I ,
o*vt" C 0 - INJ ChO n CM 0o 0 In cm ~ C at 0'ar%D ~ ~ t In N AC D 04 Or NY 0r v D() v 0c)0 r
o %N 0, %oH N 0r 0 ,0 ,
CM In M 0 e)q V 1 U A4 .
0 vnPI 0\ N N
N ID 46464
r- A ID CID 0r'.oi Nq N6 4 N '-IM C Cm N i 0-4N C141- NI ~- N ~w Nnm C) V r
NN4 CC4)~~ C' 4 CC4 C4 C)()C C
4 Az A G A ; A ; A; 8 A ; U AA
tno o C 1P U % 0 OD0 %0 v I
N0 e 0h46 M6I I47W -
14 C cm C146 m mm A v , 4
V)t4 0N r4' In m co LnIDn U) vCh c
s~00 U) U) U 000 In Ln) n 000
108
vt- %Dco. r
-
oo coc'a N % C DH L
-% % 0CJ~ N~ DI CD q
0~H %0 V IVH m0%
N N N q -4r
0% ) 0
4J 4 C 9~N' CJ
0\0
%0 rm cr mco
%D %04 ~
LIt) %0. 0EA
. 0 r.cy v
e4 n U)U U) 0 00
109
4500
LiFE4.4000 25
__ -2S 3500 ---- 20----------"
-- -- 15 11'i__ 3000 15-=
2500 ----- 10 1
2000 5
1500 41T
4.0 4-5- 5.0 5.5 6.0 6.5 7.0 4.0 4.5 5.0 5.5 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt. of Mix
10 -- - - -146
C, ,._ ,-8 a. 145
> 6 " 144S-.- - 143
S142
4.0 4.5 .5.0 5.5 6.0 6.5 7.0 4.0 4.5 5.0 5.5 60 65 7.0
. % AC by Wt of Mix % AC by Wt of Mix
Figure C-12. Marshall Mix Design Curves for ESL.
110
4. MARSHALL MIX DESIGN DATA FOR SBS
iii
V-1 I 0 No ri fn cc ri4v co %DO ' N 0% C 0 'j lwriO t-r- 0 4 C rt r A -I ri vi t-4 C-4N('IJ i-I -i CMN t-I N N CVCV C
gqj '~CD ri L'at-40 Ot 9-1 U) %D 0 4 N '.-i cn 0 U)0 'a qv-i t- ,-4 tocm-H %D9 m CM cN C n %oa' vq cty)mTA 4 r- 0% O co 'a) o kc oqoo -00 m 0 h
cnce c) C) e) Ct) Ct) m c c m N CN CVNcm N N4 CV3N CV 04N-4
to 01in%0 c om*c TA4 q'00 %D en .tN 4 n cDNa 0 10 '0** ON %O 000 0 H4 v'q' mc vq N Jc' in' %D'occM c) m~r 0
4. 4to r-I 4 0 * # * 0 * * * .* 0 * * 0 *
v- v IV IVw-w- IV4 "r- vI v I*V I v-I v vIV- v -V r'v w v -
oco co vi~CD
Ii. I N N.r4 ~ ' k o Ch N 'j m coccc cc o o- %D 0 oi0% D .N ~ 0 4 v -i -I 0% (no' % 'aD L14 4q v Dr W o % 000 0 04cccc m N C V4 Cc c cnc CN CVNN N~ C
i C * C C C V! V! V! V! C ci I V C V! V! V! C V! C ? Ci I"! C
V C4C4N C 4CV C14 C\ C C *Q N N C N V* N .QN C Cl
U! i C! 9 Ci C CC. C *
%D %oN NNN NN N N NN - NN l. r N N
D 0 ;U ; C 1001 000 10 00 A ;0101;0 000.~ N CC rz2 m. CY* v. m2 .** wn V *..U nv )
*~~~~~~~ 44 001 001 olt tt
IV -iN %D* N-~c 0t 0-%c m3 04~c C14 -N %0 Ln v-lc m vlc q
9 4t C;U;C44 t 44 ; ; ; C U 112 1
-- 4000 - 25-- I I ___
- 0 _
3500 - _, 20
3000 - 15- ..- --- P"
IAIS2500----------
2000-5
1500 LL4.0 4.5 " 5.0 5.5 6.0 6.5 7.0 4.0 4.5 5.0 5.5 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt. of Mix
10j--i- 146 - - - -riij
8-- -- -- -- -L 145Al I
I 6
6- 144
2, 142-
141-- -
lalI I *
4. 4. -5. 5./. . . . .5 50 5 . . .omy~o Mi %A b W f'i
Fiur C63 Mashl Mi einCrvsfrS
5. MARSHALL MIX DESIGN DATA FOR PP
114
0% D (1 0 m q % 1 0 cl cy ) N C4 m v*rm mir HHH rq HHH ) % (4 H
v U) 0 m0 L.On' H4 N 0 0 Oi N Ln o eC') 0 t coI r-9 '0 V l MO U; 0z OUC; U) 0U V
0 41l ClNUCJ ~ 00 ~ )C 'C
o 0~0
CV 0
1%C04 Ce) 0CI 04 0'~ V' V01 rj% D n M H H U)Cln l 0 l) clclc' wl m1C)' %0) vC' n n v VIVC') ) C C V1) C
14
9 C ri%0 rH r4-c 0%U)H mcU),
o i0 tI q 1 '0H qHH q
in 00 U1) 000 ))%D 00inrin0 t
U! U!U U! U!U! U!o' *00'
115
45000---, - - -
T 4000 "--- 25
" 3500 - t 20
3000 ---------- 5
2500 10
2000 5
1500 IH H IIIIE j0E4.0 4.5 5.0 5.5 6.0 6.5 7.0 4.0 4.5 5.0 5.5 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt. of Mix
7 --. 149
6---- 148
U.5 CL 14
4.14
>.. 146 -,.
3. 1455 / - -
2 144
1 1434.0 4.5 -5.0 "5.5 6.0 6.5 7.0 4.0 4.5 5.0 5.5 6.0 65 7.0
% AC by Wt of Mix % AC by Wt of Mix
Figure C-14. Marshall Mix Design Curves for PP.
116
6. MARSHALL MIX DESIGN DATA FOR ER
J.17
4Ji H i H Ir4VH HtI H
N mN r- NAC N mC n in ~ m~ co N) r, r nen 0 t V V n i l m r%.cm %0 %0 CDcM)Ul 04
Ch c IV V 0 v-1V O MW rN 4%D C W '0 0 r(V)(Y c C % ON~ N~c 4 c~c at) mr N 0 N r)C H co
4.4 9 0 0 0 0 0 9 . 0 .
o 0 "rC'
04 0
44 N D % s *4ri04 N Nn 0 4 c N () r4C
CN4N N C CV N N N N N NN04c N N NN N 0
N vDIVco %0D t-4HqH C'JH4'rl
A ; O 9.N t.4' O4 0, 8 r0i .sfl Oc0r 000 000 0 4 H 0 Hq
%D%%0 r - -r- .r N cr% r- l -N
g 4 co cLn o *Hw*D h U)c' n0 C 0 %-I
m %D 0 ' iNc 'N t' %DU)'VA C') 0 OD 0
0%D 04' coi cow - o % hNat 0ChLA %0 W N N N ) ) Lo44 46u)41I l n U) U
4La) in in 0 00 i!ni!i0 0 00 in n u)q;* ;i ;c U; U;U nc nz%0cI % Z-
L H NC' M 1 H N m 1 i HN m 1 W1 HNC m4 HNC M
118
I I I
4000-- - -
.- "-1 I - -
- 3500 - - 20 ), , Ii1" q _
3000-- - 15
" 2500 - 1" 0
2000-- 5
1500 04.0 4.5' 5.0 5.5 6.0. 6.5 7.0 4.0 4.5 5.0 5.5 6.0 65 7.0
% AC by Wt of Mix % AC by Wt. of Mix
146 --
10 145 --- --- --
8-o. 144
6 -2 143-
4 .2 142
2 141 --
14.0 4.5 5.0 5.5 6.0 66 7O 4.0 4.5 5.0 5.5 6.0 6.5 7.0
. % AC by Wt of Mix % AC by Wt of Mix
Figure C-15. Marshall Mix Design Curves for ER.
119
7. MARSHALL MIX DESIGN DATA FOR EVA
120
%D
'0) m 'm0 D
r-I i rqt-I ii e T-H t'I H-- i-I 0 NNN4 *
r-I
V 0 V'O M~ C CID Cf) .'r- C) Nj%4 CDO % O DI~ 1l
v M0 L ni UttlC c' CV qr IVC' CV0 N'Lf0% 0
v inOD 0V iOn C - OD a'%1v'e 0 %Q4 ILO C%0 f
0% 0O' co 0 9 C 'f 0 IV~~ MO M % C O C 0 4 fL '
o ' N n '4. 4U . r: C. CoV
"r% Ou) Nnt n L nL e n% U ;
vcov v 4 rv I w w v 1 wqTA q ti r t- ti rI v riri -i H COv - T AH r
o IN N cc
N N N NN NmN N
44 ~o CO40 OH')mcn m m n v~r o (Y) vNc
j3 NLAC mO riooHC 4U) ot m co %0 r OH HHviTq H HHHi HI-i- HHN- c
0-r- cr, r, -- r-r -r--t
o% N LA N qw v4 O MN o H0 HU)H r
cO44'H~~ 44C4U NN (41)
CD M 0 m N'44 N N t.C')44m NN
4~CO f rcuo r.Um o rq o, oco L ooN NOco coCO co as No 0 w % 4 a
NN N NN N,9 9 N N N NN N N N
000 U ) u)) 000 U)U)nU) 000
0% .; U; CO
.;. .N r C O . .C4 cn
121
- (5000 i0- - I _ Lj~
4500 i] 3: 25
U-
4000- 200 - ,
- 3500 15
--- - ~---- - -- - -
3000 10 'y M
2500 - __j 54.5 5.0. 5.5 6.0 6.5. 7.0 4.5 5.0 5.5 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt of Mix
a,.8 147
6 146 A-
4" 145 - - /
2 "144-
4.5 5.0 .5.5 6.0 6.5 7.0 4.5 5.0 55 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt of Mix
Figure C-16. Marshall Mix Design Curves for EVA.
122
8. MARSHALL MIX DESIGN DATA FOR FCB/AC-20
123
4~ cw)Ow-4i 0 CiV * OCY) 0 %D D0ID rN
H Hi eq O i D W r O- O w0 %DP % - l H H v-4CNJH Hi
wr Vz4 0A L 1 DH 0 %Lr i0 o O DC
" 0 HI CV t N %, 0 ri %D~ NV i LAn M % (nc 0% CM0 ODv o 0H LA NNO 4 C H HHq iv IN 04 r- 0 %D c m N V'0C M -
43- 44I * * 9
el ri- H HH H H HHr -I H HH rrH H I H H H H -4
0 LA Hr
N '
0 Ch
r-%~DH OD qrN0 I LA'0 %ori Cr) %D N N D 'DOL 0 Ctm mH
44 % - % D v0% 0% C4 0t-40I C)lw% . V % %DLA -) %L-I I~ CV *q C\ Ir *1 Ca a ~ .f CV If e . 1 l)m m c
C444 4C4444 cON O40 LAVC4 C4' OO4C444 4
co 0 C* * 00 0 * 0 *i l I I CV *~ ~ Y iC
H 0 0 tn %DN N C;C; 9 OLA 9 0t-4'GA0(Y) c)cIr) M C) N v e Vv VI 'Ln Ln %DLA i
0 0o CIOA %DC4 DN %Dr4 %0LA cON )ODID c4%$4 MI IN (r m CM m v a IV IV w an .n %D *
000 LALW coL 0C~ H'0
A L Ln LA 000 LA LnL) 000 L)AL)LI 000
124
.0I I
4 500 20
j 5oo0- -, _ 0----------
o . 0
, 4000 15U) U) 4 0"
_ 3500 --- 1
3000 I
2500 1-- - -
- -IL...
4.5 5.0. 5.5 6.0 6.5 7.0 4.5 5.0 5.5 6.0 6.5
% AC by Wt of Mix % AC by Wt. of Mix
8-- 148
J0 147 A"
- - -- -- - - -
i0 1
8 i 146,
> 6 Z; 145-
o 4 144
143--AL
- - 1 3 4 2 vi4.5 5.0 5.5 6.0 4.5 5.0 55 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt of Mix
Figure C-17. Marshall Mix Design Curves for FCB/AC-20.
3.25
9. MARSHALL MIX DESIGN DATA FOR FCB/AC-10
126
4 C?
001- j 0 0 0%~ t Co O IChO 0 Hqr-i o 0 U)OImU) %0Vz4 rii -I i-I 14 H-14. H - rq HH H
0 rio o (1 -4 as4 OC0N Oq U) o U) IV V C Cil~p NC Nr %Do r- 0 o 0 () El- NIren NV NO0% v UO%S i Uco %D NO O % r-'C U HD %D-- at4 'o C-4 w LA'n N4 rLn v e vV rI q C)Com m Ce) crJC14C N
~COD C 0 r-~ a - Co 0 O D m OD C qe-4 N NNHr-- ) w H IV- 4 ~ CV) v c') %0o acq O % U) t.~r %0 0 0Cm44 .4 . . u; u* * u* G u; G G G G tI G G
o qHr i ririr q r ir i r H q U) H 0
0 o\0 Ln
N.
04O N '''' N O CV) CO,- - N N ) '
44 Co N r Co q 'H c') c') m-c)~ v c') u)l U v ULn ) M~'~ V IVNr NN4 N1 CV c') C 'C)CY) (I) Cen1)Cmm'mmCw) cr) c') c') P) CV)
0%)~O q0 ir H' Y-H C4cilCoO 4%o , %0 * l .- l N r . *l *l r *
m' NN) WN N'0 %0v com0 8 4 CNG43 n q " Ncy)C Cc)qw' nU U)Co H LIn U)
N N *o * v *Y *l *qr 10Cq%4 14 U' N'0';' CoO 0 Oq'; N C C U A14 mcq'IE ce)C)V M U) nHu) t-4U)%
Nco m e W-0 iN ON '0 V
L p I r-~ u) U c) Ch OI-4 q flw 0 MOCD
04 0 0 U)U)U)L 0 0 0
9n U)U) 0 0 0D C'
L i 14 Nc') ru;C4 H cy;c) F ' H'Cw4') 'T- HNC~q') M N
127
= 5000 - I25_- - , ,"
4500 -_20--I N11.21\ U-
4000 1
3000 5 5 '"
2500-4.5 5.0. 5.5 6.0 6.5 7.0 4.5 5.0 55 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt. of Mix
I I - --
10 146
0. 145
6 - - - - - - - 144
... • 143
2142 ...
141 i
4.5 5.0 ..53 6.0 6. 7.0 4.5 5.0 5.5 6.0 6.5 7.0
% AC by Wt of Mix % AC by Wt of Mix
igure C-18. Marshall Mix Design Curves 'for FCB/AC-10.
128
APPENDIX D
TEST RESULTS OF AGED SAMPLES
1 29
H 0 m~ N- ml m 0 ( H N 'I1 0 N CN CN H 0- l
*. 0 * *H 0U) H 0 0U) H 0; 0 0
N~~0 %~C D O D N0 In CN N H 0 0)~ N co 'kD0 0 N N H H
o 0 0 0 0 0 0
o Nr H- H H (3) N Cl)S0 N 00 O cc) IZ 0 m~ '3 cn NI Cl H 0 0 0 1 l H H
*0 * *0 * * *H 0 0 0 0 H 0 0 0 0;z
x.1iLn N k.D O N- N, 0O N0 N- %D U) 0 0 rr 0 mY 0"
t-- H- 0 0 0 0 tb. H- H- H- 0 0
P 0 o o H H- 0N Dl< k Cl Cl 0 N 'O0 l0 0 0 0 ClH0 0 0
0 0 0 0 H0 0 0 0
U)U
WL-1HLLA 0 0 WA ri Lf
q C L N Nl Ln ' LHw 0 0 0H 0 0 0
Z 0 0 0 0 0 0 0 0
z 0HL 0 0 0 0 HL 0 0 0
H ~ u)
0 ____130
_~k N 'Ce l) Cl)VH 0 N LO toH c H (A
I 0 N N1 C1 N I 0 (n fl) m H
04 P
00 U) N 1O 0 kD m lo 0 H CN N 0 co co co CNo0 H 0 H H H H
oD 0- 0 0 0n 0 0 0)
0 0 CO Nl N 0 10
z0 * * *0.
H H 0000H 0 00
04-) ~ ~4)0 N 10 N
0 10 10 %D '0 ' ' O O
=t H 0 0 0 0 bD H 0 0 0 0
0V 0 0 0 0l 0 0 0
E1
r- 0 D 0H C 0) 0fH N S 1 l
Hz 0 0 0 0 0 0 00
H 000 0 0
o0 0 0004
P4 U) CO-
O * 1 00 0w rI1 0 0 00 U H L O 0 0 0 1H H Lr CO '0
H~ ~ P4H P
~~~ *QC0 ~C 0 0 CH* C HH 1 00 0 0 0 0
H- H- N i-1
'-H
0 00 0 0 0
(9 ~ 0 0 0 ~ 0101
M lzr OD -(o' 1toH0 N H 0 LA m' 0 m~
*r-l 0 **-U) H 0 0 0 0 H 0 0 0 0
N ~)0 ~~ 0H Q)o ko N to O 0 Ol 0) H Noo0000 0 0 H- H-
0 0 0 00000
S 0 LA) LA) LA %D r- 0 D N- tO
H 0 0
o x
-) ON to ko 4.) ko to k H= - 0 ml ml o LA Ir LO %D
(9~H 0 0 0 0 t-, H 0 0 0 0
CC) (3) H- o H -N Ch Nr N (q m N W m1 Cl IT
0- Y 0 0 0 0 0 0 0
mH H q H 0 OD (A N\Nq N N N m Nq N (n
wH 0 0 0 0 H0 0 0 0
0 ,qL 0 0 0 0Or4L 0 0 0
U) U)
oo NCni )Q w HL 0 0 0 w HL 0 0 0
0 H) H- Lf o '0 0 U1 H LO 0 '0H~ ~ H E' 4
* Qt 0 0 H 0 ~t 0 0 H
E-1 0 0 0 0 -~0 0 0 0
H *4 w H4 .I * *
132
- co N N % H 0 N 0H 0 0 MA 00 qz H 0 MA CO O LA
I 0 HA N (N (N 1 0 H- H- H- Hq* 0 * r-I 0 .
UH 0 0 0 0 U) H 0 0 0 0;
o LA) el LA Hq r O LA* 0 0 0 N~ (1) 0 O3) m' 0 O')
0 H H H- H- 0 0 0 H 0
o 0 0 0 0 00
CA O) H ml 'D r, co LA
S 0 %l %D C OD~ M ~D I ONz IC 0 0 0 0 ICH 0 * . * .0* * .
H- H- 0 00 0 0 0 0z
4.) m~ N LA tD 4-) 0O0 1 a% O LA0 lc~ lq LA '.0' 0 IIC q: LA %D
z -)rf0 0 0 0 H0 0 0 0
r- q C 0 N O 0
E- m c tCl (f) m LA
Cl0 0 0 0 ml 0 0 0 0
uCi0 0 0 0 rI0 0 0 0
H __
0 U
U)
N 0l L 0 0 0 0 rjL 0 0 0
o% w UTw oV mH)U) U)
0 -4L 0 0 0 Q wr L 0 0 0U) H- r- LO 0 0U0 ) H m 0o 0H ~~ N i
H C0C 0 0 H 0~QC 0 0 H
t~~ 0 0 0 0 S0 0 0 0
H r4 *4 * C .4 H r1 *
0
133
co 0 LA cn
I 0 N N N H-
0 T 'cr LA NO, H- H- H- H
H H N 0I ~ H H- H H
0
0 13 00 0 0
4.F) rq 0) 0
'- 0 co o coH- %b %D %0 0 0o
fi m 0 0 0 0
0 0 c o
m. 000
z rq0 0 0 0
_4 LC 0 '0 0
in C0 N3 to
0 H 0 0n 0 0
H_ 0 0 0 0
I-T
P4
C)134
* 03
* iCD* I4
* 00 LO
* * * *
cu c
135)
0* 0
CD I
OD)
a40
o4-1V. co
4-)
LU) 0
0 * 0
100
0 4-1
4
0 Hl* *r:4
00
00*0-0cu * cx
* 136
0_____ _______0
* I.IEn* Ia
* .1* 1 .0
* I
0-0 U4
.1 * * I ci 40
ojo* ~ J U
LLciC: *u
0 0 04C* 0u
117
0000
00
L
LI)
4J3
*E.140 * 0
'IT
* * U
CL L I-.j
0 0 0
uJu
138
0)0
CL u
0 c0u 0J
* 0
CD 4U
0 0 4
00
0 o LO
(0H
C.-
0 0C0
139
0I ~~ 0
00
Q)
004
* *0 0* * L0
0 0
0 0m CU)
140)
00
• I 0
I. i i 0
II * i 0I.* - 0
\I I -I
0
* I]1
o ,
S0 3 ** '
\ I\*i ix
* *00
141U0 Ia
0 LO
14
*n 0
I T)
** 141
0 0 00*. n I J"
00
00
I -4
00
-0 7C)
0 0:
* 1:1
142
* OD
** I4
* 0
0~
00
o 04rz
* 0
V)
LUO
C-
0 0 0 00
143
APPENDIX E
OPTIMUM ASPHALT CONTENT CALCULATIONS
144
1. OPTIMUM ASPHALT CONTENT CALCULATION AC-20
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.00
Asphalt Content at 4% Air Voids ........................... 5.40
Asphalt Content at Maximum Stability ...................... 5.50
Optimum Asphalt Content, Average 5.6
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 4040 lbs.
Unit Weight 147.3 pcf
Air Voids 3.0 %
Flow 13
Remarks:
Marshall design data for AC-20 Mixture meets Air Force AFM 88-6wearing course criteria.
145
2. OPTIMUM ASPHALT CONTENT CALCULATIONS, AC-10
PERCENT
Asphalt Content at Maximum Unit Weight .................... 5.7
Asphalt Content at 4% Air Voids ........................... 5.2
Asphalt Content at Maximum Stability ...................... 5.3
Optimum Asphalt Content, Average 5.4
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 4200 lbs.
Unit Weight 147.7 pcf
Air Voids 3.7 %
Flow 16
Remarks:
Marshall design data for AC-10 Mixture meets Air Force AFM 88-6wearing course criteria.
146
3. OPTIMUM ASPHALT CONTENT CALCULATIONS, ESL
PERCENT
Asphalt Content at Maximum Unit Weight .................... 5.75
Asphalt Content at 4% Air Voids ........................... 5.75
Asphalt Content at Maximum Stability ...................... 4.25
Optimum Asphalt Content, Average 5.3
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 3750 lbs.
Unit Weight 142.5 pcf
Air Voids 4.5 %
Flow 11.5
Remarks:
Marshall design data for ESL Mixture meets Air Force AFM 88-6wearing course criteria.
147
4. OPTIMUM ASPHALT CONTENT CALCULATION SBS
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.00
Asphalt Content at 4% Air Voids ........................... 5.6
Asphalt Content at Maximum Stability ...................... 4.5
Optimum Asphalt Content, Average 5.4
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 2950 lbs.
Unit Weight 145.1 pcf
Air Voids 4.25%
Flow 13
Remarks:
Marshall design data for SBS Mixture meets Air Force AFM 88-6wearing course criteria.
148
5. OPTIMUM ASPHALT CONTENT CALCULATIONS, PP
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.00
Asphalt Content at 4% Air Voids ........................... 6.00
Asphalt Content at Maximum Stability ...................... 6.00
Optimum Asphalt Content, Average 6.0
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 4000 lbs.
Unit Weight 146.6 pcf
Air Voids 4.0 %
Flow 12
Remarks:
Marshall design data for PP Mixture meets Air Force AFM 88-6wearing course criteria.
149
6. OPTIMUM ASPHALT CONTENT CALCULATIONS, ER
PERCENT
Asphalt Content at Maximum Unit Weight .................... 5.70
Asphalt Content at 4% Air Voids ........................... 5.8
Asphalt Content at Maximum Stability ...................... 5.2
Optimum Asphalt Content, Average 5.6
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 3250 lbs.
Unit Weight 145.5 pcf
Air Voids 4.5 %
Flow 11
Remarks:
Marshall design data for ER Mixture meets Air Force AFM 88-6wearing course criteria.
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7. OPTIMUM ASPHALT CONTENT CALCULATIONS, EVA
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.5
Asphalt Content at 4% Air Voids ........................... 5.75
Asphalt Content at Maximum Stability ...................... 5.50
Optimum Asphalt Content, Average 5.9
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 4200 lbs.
Unit Weight 145.7 pcf
Air Voids 3.7 %
Flow 13
Remarks:
Marshall design data for EVA Mixture meets Air Force AFM 88-6wearing course criteria.
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8. OPTIMUM ASPHALT CONTENT CALCULATIONS, FCB/AC-20
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.75
Asphalt Content at 4% Air Voids ........................... 6.10
Asphalt Content at Maximum Stability ...................... 5.50
Optimum Asphalt Content, Average 6.10
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 5000 lbs.
Unit Weight 146.5 pcf
Air Voids 4.0 %
Flow 10
Remarks:
Marshall design data for FCB/AC-20 Mixture meets Air ForceAFM 88-6 wearing course criteria.
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9. OPTIMUM ASPHALT CONTENT CALCULATION FCB/AC-10
PERCENT
Asphalt Content at Maximum Unit Weight .................... 6.50
Asphalt Content at 4% Air Voids ........................... 6.25
Asphalt Content at Maximum Stability ...................... 5.25
Optimum Asphalt Content, Average 6.0
Marshall Design Data From the Above Optimum AC Content:
Marshall Stability 4150 lbs.
Unit Weight 146.4 pcf
Air Voids 4.2 %
Flow 10
Remarks:
Marshall design data for FCB/AC-10 Mixture meets Air ForceAFM 88-6 wearing course criteria.
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