COMPARISONS OF RUBBERIZED ASPHALT BINDERS: Asphalt … · The utilization of crumb rubber modifier...

______________________________________________________________________________COMPARISONS OF RUBBERIZED ASPHALT BINDERSAsphalt-Rubber and Terminal Blend

Shakir Shatnawi PhD PE

President Shatec Engineering Consultants LLCEl Dorado Hills CA 95762Phone 916-990-6488Email sshatnawishatecnet______________________________________________________________________________ABSTRACT The paper provides a comparison between two different rubberized asphaltbinders namely asphalt rubber and terminal blend It discusses the two processes used toincorporate recycled tire rubber in hot mix asphalt and seal coats The paper delves intothe performance history field test section accelerated pavement testing laboratoryperformance tests binder properties film thickness application rates and specificationrequirements of the two binder types It concludes that asphalt rubber and terminal blendbinders are distinct from each other and possess completely different characteristics Eachof these binders has its own properties and unique applications

KEY WORDS asphalt rubber terminal blend binder properties binder tests performance PGgrading recycled tire rubber hot mixes chip seals application rates gap-graded dense gradedopen graded performance fatigue permanent deformation thermal cracking reflective cracking______________________________________________________________________________

2 COMPARISONS OF RUBBERIZED ASPHALT BINDERS Asphalt-Rubber and Terminal Blend

1 Introduction

This paper discusses the two processes used to incorporate recycled tire rubber in hot mixasphalt and seal coats These two processes are distinct and produce two completely differentbinders namely Asphalt-Rubber and Terminal Blend (Figures 1 and 2) Each of these binders hasits own properties and unique applications

The utilization of crumb rubber modifier (CRM) in asphalt mixtures is intended to improvethe properties of binder by reducing the binderrsquos inherent temperature susceptibility Theaddition of rubber into the binder increases the elasticity and resilience of the binder It improvesthe durability and resistance to fatigue and reflective cracking in hot mixes and chip sealapplications There are environmental benefits to the utilization of the tire rubber in asphaltpavements and diverting this hazardous waste from landfills

11 Asphalt-Rubber

Asphalt-Rubber (Figure 1) has been known historically as the ldquowet processrdquo and has beensuccessfully utilized for over 35 years in Arizona California and other states It is defined by ASTMas ldquoA blend of asphalt binder reclaimed tire rubber and certain additives in which the rubbercomponent is at least 15 percent by weight of the total blend and has reacted in the hot asphaltbinder sufficiently to cause swelling of the rubber particlesrdquo [1]

Asphalt-Rubber is a non-homogeneous composite consisting of liquid asphalt and rubbersolid particles It is believed that during the interaction with asphalt binder the CRM particles inasphalt-rubber absorb a portion of the oils in asphalt binder and the particles swell thereforeincreasing the viscosity and stiffness of the CRM binder

There are two types of asphalt-rubber binder Type I and II Type I is mainly used inArizona and Texas It contains asphalt binder and 18 to 20 percent tire rubber that meet a specificgradation requirement Type II is used in California and consists of about 20 percent rubber (75percent ground tire rubber with a suitable grading and 25 percent natural rubber also with asuitable grading) In addition heavy aromatic oils (asphalt modifier) may be added up to 6percent Type I and Type II binders are used internationally The asphalt-rubber binder is blendedusing a low shear system for a minimum of 45 minutes [2]

COMPARISONS OF RUBBERIZED ASPHALT BINDERS Asphalt-Rubber and Terminal Blend 3

12 Terminal BlendTerminal blend binders have been used since the mid 1980s in Florida and Texas and later

on in California Colorado Louisiana Arizona and Nevada Additionally terminal blend productshave been used in slurry seal applications Terminal Blend binders can be patented andorproprietary However the Terminal Blend binder can be performance graded (PG) and AC gradedand comes with a variety of grades such as PG64-28TR PG70-22TR MAC-10TR MAC-15TR andalso being emulsified

The amount of rubber used in the Terminal Blend process may vary anywhere between 5to 20 percent It is important to note that an independent test verification of actual rubberpercentage has not been developed to date Terminal Blends utilizes a fine mesh of crumb rubberderived from 100 tire rubber and blended in the refinery or stationary asphalt terminal withasphalt binder and the component materials are heated over an extended period of time Thisresults in dissolving of the rubber particles (Figure 2) The Terminal Blend binder has a goodstorage life with no separation due to the process that integrates the rubber into the asphalt andit is manufactured similar to polymer modified asphalt The Terminal Blend binder is now usingthe PG grading specification system similar to polymer modified binders (Table 1) (PCCAS 2008)[3]

2 Strategies

There have many applications and strategies that utilize rubber modified binders Forexample Asphalt-Rubber binders have been used in open graded gap graded and dense gradedmixes and in chip seal applications and interlayers These applications have been known withdifferent acronyms that refer to the same application or process For clarification and to avoid anyconfusion Table 2 provides side by side comparisons for some commonly used acronymsconcerning Asphalt-Rubber systems

Figure 1 Asphalt-Rubber Binder Figure 2 Terminal Blend Binder


SpecificationGrade

Property Test MethodPG 64-28 TR PG 76-22 TR

Original BinderFlash Point Minimum degC D 92 230 230Solubility minimum D 5546 or D 2042b 975 975Viscosity at 135degC c

Maximum PasD 4402

30 30Dynamic Shear

Test Temp at 10 rads degCMinimum Gsin(delta) kPa

D 717564100

76100

RTFO Test Mass Loss Maximum

D 2872100 100

RTFO Test Aged BinderDynamic Shear


D 717564220

76220

Elastic RecoveryTest Temp degCMinimum recovery

D 6084 Method B2575

2565

PAVe AgingTemperature degC

D 6521100 110

RTFO Test and PAV Aged BinderDynamic Shear

Test Temp at 10 rads degCMaximum Gsin(delta) kPa

D 7175225000

315000

Creep StiffnessTest Temperature degCMaximum S-value MPaMinimum M-value

D 6648-183000300

-123000300

Notesa PG-TR grades require a minimum of 10 percent by weight ground tire rubber contentb D 5546 is allowed as an alternate test to D 2042c This specification may be waived if the supplier certifies the asphalt binder can be adequately

pumped and mixed at temperatures meeting applicable safety standardsd In desert climates the PAV aging temperature may be specified as 110 degCe PAV means Pressurized Aging Vessel

Table 1 Performance Graded Tire Rubber Modified Asphalt Binder [3]


As shown in Table 2 Asphalt-Rubber chip seals can be referred to as SAM ARSC or ARAMwhich stand for stress absorbing membrane Asphalt-Rubber seal coat or Asphalt-RubberAggregate Membrane respectively Interlayers are referred to as SAMI in Arizona and SAMI-R orARAMI in California denoting stress absorbing membrane interlayer (ldquoRrdquo for rubber) or Asphalt-Rubber aggregate membrane interlayer which are the same application process

Open graded mixes can be referred to as Asphalt-Rubber friction course (ARFC) andRHMA-O or ARHM-OG denoting rubberized hot mix asphalt with ldquoOrdquo or ldquoOGrdquo for open graded orRAC-O denoting rubberized asphalt concrete Gap graded mixes can be referred to as Asphalt-Rubber asphalt concrete (ARAC) in Arizona and RHMA-G ARHM-GG or RAC-G in California All ofthese terms have one commonality they all use Asphalt-Rubber binder

Strategy Arizona Current Caltrans Greenbook andOthers

PreviousCaltrans

Chip Seals SAM ARSC ARAMInterlayers SAMI SAMI-R ARAMIOpen Graded RHMA-O ARHM-OG RAC-OOpen Graded-High Binder

ARFC RHMA-O-HB

Gap Graded ARAC RHMA-G ARHM-GG RAC-GDense Graded RHMA-D ARHM-DG RAC-D Strategies used in the ldquoStandard Specifications for Public Works Constructionrdquo ndash TheldquoGreenbookrdquo

Table 2 Common Acronyms

Asphalt-Rubber binder has been used on all of the above strategies These strategies havebeen used successfully on many projects However Asphalt-Rubber is not recommended for useon dense graded hot mix projects since the dense gradation cannot adequately accommodate therubber particle size On the other hand Terminal Blend binders are more suitable for densegraded mixes


3 Historical Perspective

Several pioneering states including Arizona California Texas and Florida and somecountries have been using recycled tire rubber in Asphalt-Rubber chip seal applications since theearly 1970s and in hot mix applications since the mid 1980s Early trials included the use of boththe Asphalt-Rubber wet process and the dry process of incorporating recycled rubber howevermost of the work completed in the 1990s and in this decade has employed the Asphalt-Rubber

wet process As a result of all of these many trials test sections and research activitiesspecifications and practices have improved and construction procedures have been refined toprovide consistently good performance

There have been many efforts and investigations on Asphalt-Rubber and Terminal Blendproducts Below is only a list of some of these activities 1999 - 2003 Heavy Vehicle Simulation on several field constructed overlay test sections 1997 - 2003 10 pilot projects using modified binder and 5 using warranty specifications 2004 - 2005 Two field full scale experiments (total 13 test sections) 2005 Field projects (rubberized bonded wearing course) Quieter pavements using open-graded high binder (HB) Recycling of HMA containing Asphalt-Rubber Full-Depth Recycling (FDR) of projects containing Asphalt-Rubber chip seals or interlayers

Additionally field condition surveys of Asphalt-Rubber projects were conducted in Californiaon over 100 projects in 1995 and on over 210 projects in 2001 that showed superior fieldperformance over conventional strategies

A 2005 Assembly Bill (AB338) in California called for progressive amount of usage of tirerubber in paving materials over several years The Bill mandates increased usage of rubber inpaving materials from 20 percent in 2007 to 35 percent in 2013 By 2010 Caltrans reached anamount of over 30 percent of the total hot mix asphalt projects

The growing demand for rubberized asphalt technology requires the use of effectivespecifications and guidelines to ensure its continued successful performance Some of thistechnical guidance is included in the following

1992 Reduced Thickness Guidelines (for Asphalt-Rubber) [4] 2002 Asphalt-Rubber Usage Guide (for Asphalt-Rubber) [5]


2003 Maintenance Technical Advisory Guide (MTAG) (for Asphalt-Rubber and TerminalBlend) [6]

2006 Updated Asphalt-Rubber Usage Guide (for Asphalt-Rubber and Terminal Blend) [6] 2007 MTAG 2nd Edition (for Asphalt-Rubber and Terminal Blend) [6]

4 Case Studies

Direct performance comparisons between Asphalt-Rubber and Terminal Blend have beenlimited since the Terminal Blend technology has been evolving over the years Below are severalcase studies that have investigated the two binders

41 ALF Test Sections

A pooled fund study was conducted in 2002 at Turner-Fairbank Highway Research Centerin McLean Virginia where twelve lanes of HMA were constructed with various modified asphaltsTwo of the test lanes used crumb rubber material technology Lane 1 employed the Arizona wetprocess (CR-AZ) and Lane 5 employed the Texas Terminal Blend process (CR-TB) Lane 2 wasconstructed with an unmodified asphalt binder as the control section Other lanes included air-blown polymer and fiber modified asphalt binders Note that all sections were dense graded withfull thickness and only the CR-AZ was gap graded at 50 percent reduced thickness

Laboratory performance tests were conducted on all mixes The test sections underwentaccelerated pavement testing using the Accelerated Pavement Facility (ALF) machine at 19ordm CThe results showed that the CR-AZ test performed the best in terms of fatigue and reflectivecracking (Figures 3 and 4) The authors indicated the base for the CR-AZ test section was stifferthan the rest of the test sections Post-mortem evaluation was conducted 10 months later bytaking core samples to investigate the conventional HMA dense graded layer (control mix) belowthe Asphalt Rubber CR-AZ mix It was found that all cores in this layer exhibited bottom-up cracksafter 300 loading applications and that most cracks did not reflect through the Asphalt RubberCR-AZ gap graded layer This finding can be an indication of the reflective cracking resistance ofthe Asphalt Rubber gap graded layer This important finding further validates Caltrans reducedthickness design for Asphalt Rubber gap graded overlays as compared with conventional densegraded overlays and validates previous studies showing the superior reflective crackingperformance of Asphalt-Rubber mixes


The CR-TB Terminal Blend section showed better fatigue cracking resistance than thecontrol Lane 2 and Lane 3 with air-blown asphalt but worse than other types of modified binderlanes ALF rutting at 64ordm C showed CR-TB as having the highest rut resistance while the CR-AZshowed similar rut resistance as the rest of the sections [7]

Figure 3 Distress of ALF Test Sections [7]



42 HVS Test SectionsRecent Heavy Vehicle Simulator (HVS) tests were conducted to evaluate the performance

of several rubberized HMA mixes in 2001 at the University of California Richmond Field Station(Bejarano et al 2005) [8] (Steven et al 2007) [9] (Jones et al 2007) [10] The following mixeswere used in the evaluation 1) MB4-G Terminal Blend gap graded mix with 7 percent ground tirerubber 2) MB4-15-GTerminal Blend gap graded mix with 15 percent minimum ground tirerubber 3) MAC-15TR-GTerminal Blend gap graded mix with 15 percent minimum ground tirerubber 4) RAC-G Asphalt-Rubber hot mix gap graded mix and 5) AR 4000-D dense gradedasphalt concrete mix The rubberized sections were placed at 45 mm while the DGAC sectionswere placed at 90 mm thickness The design binder content for the various mixes is shown inTable 3 The actual binder contents that were extracted through the ignition extraction test andthe as-built air void contents are shown in Table 4

Gap Graded Mixes Dense Graded MixesAsphalt Rubber 80 AR4000 50

MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64

Table 3 Design Binder Content [8]

Extracted Binder Contents As-built Air VoidsAsphalt Rubber 849 Asphalt Rubber 88

MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65

AR4000 613 AR4000 71Table 4 Actual Binder Content Used from Ignition Oven Extractions [8]

The reflective cracking performance for each of the overlays was reported to be the bestfor the Terminal Blend mixes followed by the Asphalt-Rubber section The dense graded HMAshowed the poorest performance (Table 5) The authors indicated that the ldquogap-graded mixeswith seven and fifteen percent recycled tire rubber provided superior performance in terms of


reflection cracking compared to the DGAC and RAC-G mixes when used in thin overlays oncracked asphalt pavements With regard to rutting performance conventional DGAC was clearlysuperior to all other mixes followed by the RAC-G and then the modified binder mixesrdquo Theseresults were similar to the laboratory beam fatigue tests in terms of their relative ranking Theauthorsrsquo recommendations were that the Terminal Blend binders studied (MB4 MB4 with 15percent rubber and MAC15TR) could be used in appropriately designed half thickness overlaymixes for reflection cracking applications where RAC-G would normally be considered

Rank Section ESALS to 25mmmmReflective Cracking

1 45 mm MAC15-G No cracking after 91 million1 45 mm MB15-G No cracking after 88 million1 45 mm MB4-G No cracking after 66 million1 90 mm MB4-G No cracking after 37 million5 45 mm RAC-G 60 million6 90 mm AR4000 DGAC 16 million

Table 5 Reflective Cracking Ranking of HVS Test Sections Test Conditions-60kN20C 720kPaDural Pressure Bi-directional with Wander [8]

The rutting performance results showed the conventional DGAC test section to besuperior over the other sections followed by the Asphalt-Rubber and Terminal Blend sections(Figure 5) The remaining Terminal Blend sections showed the poorest rutting resistance Theauthors stated that there would be potentially a greater risk of rutting compared to RAC-G ifthese mixes were to be used under slow moving heavy truck traffic in hot climates and hencethey should not be used in locations with these conditions until proven in pilot projects on in-service highways It should be noted that the reason for the higher rutting performance of theTerminal Blend sections in this experiment may be attributed to the selection of higher optimumbinder contents than usual for these types of mixes


Figure 5 Rutting under HVS Testing Test Conditions-60 kN 50CChannelized 720 kPa Dual Tire Uni-directional [8]

The results from this study contradict the results from the ALF study This may be due tothe higher binder content of the Terminal Blends used in the HVS study of roughly 76 percent byweight of aggregate as compared to the binder content of the Terminal Blend which was 56percent by weight of aggregate in the ALF study The higher binder content in the Terminal Blendcan be the contributing factor to the poor rutting performance in some of the Terminal Blendsections Also in terms of the fatigue life results the effect of air voids may be a contributingfactor For example the actual air void content for the Asphalt-Rubber section was 88 and forthe MAC15 section was 49 Using the Asphalt Institute fatigue equation while holding othervariables constant it can be shown that the effect of this difference in air voids may result inabout 47 higher fatigue life for the case of MAC15 Note this equation was developed forconventional mixes and should not be used for rubberized mixes It was used here for illustrativepurposed only The significance of the effect of the difference in air voids on fatigue life needs tobe investigated for rubberized mixes


43 Firebaugh Test Sections

Caltrans constructed 9 test sections in June 2004 consisting of a dense graded asphaltconcrete (DGAC) a rubberized asphalt concrete-gap graded (RAC-G wet process) a rubbermodified asphalt concrete (RUMAC-GG dry process) two Terminal Blend processes containing aminimum 15 percent CRM a Type G modified binder (MB-G) and a Type D modified binder (MB-D) [11]

Based on the laboratory testing of these mixes the authors concluded the following 1)The RAC-G and RUMAC-GG mixes were generally the most rut resistant and the DGAC were theleast resistant in the Superpave Shear Test (SST) 2) the MB-G mix was the most fatigue resistantand the MB-D and DGAC mixes were the least resistant in the flexural fatigue beam test and 3)the RUMAC-GG mix had the best overall performance in the Hamburg wheel tracking test whilethe MB-D and MB-G were the poorest performers The optimum binder contents for the variousmixes were 79 percent 79 percent 63 percent 53 percent and 48 percent for RAC-G RUMAC-GG MB-G MB-D and DGAC respectively The air voids were 71 percent for RAC-G 47 percentfor RUMAC-GG 19 percent and 37 percent for MB-G 39 percent and 36 percent for MB-D and68 percent for DGAC It is well known that fatigue is significantly influenced by air voids Since theeffect of air voids on fatigue performance is well documented the large discrepancy in air voidsputs the conclusions of this study in doubt The significance of the effect of this difference onfatigue life needs to be investigated for rubberized mixes For example if one holds all othervariables constant except the air voids and uses The Asphalt Institute fatigue model the fatiguelife can be as much as 11 times more for the MB-G mix with air void levels of 19 percent and 27percent as compared with the RAC-G mix at an air void level of 71 percent The Asphalt Institutefatigue model was developed based on the performance of conventional mixes It was used toprovide an analogy on what might be the effect of air voids on rubberized mixes It is essential todevelop a model for rubberized mixes to properly quantify the effect of air voids on the fatigueperformance of these mixes

44 Chip Seals (SAM or ARAM) and Stress Absorbing Membrane Interlayers (SAMI-R or ARAMI)

The performance of Asphalt-Rubber chip seals has been good Caltrans placed 6 chip sealtest sections in Imperial County California with various specification requirements See Figure 6These tests have already resulted in significant improvements in the specifications


Rubberized stress absorbing membrane interlayers using Asphalt-Rubber (SAMI-R) havebeen widely used in rehabilitation applications SAMIs are used to retard reflective crackingprevent water intrusion and in the case of SAMI-R enhance the pavement structural value

In 1993 Caltrans constructed 11 test sections on Route 116 near Esparto Californiaconsisting of various pavement preservation strategies that included Asphalt-Rubber chip sealRAC-O RAC-G DGAC RAC-G with SAMI RAC-O with SAMI and DGAC with SAMI The performanceafter 10 years showed that the Asphalt-Rubber sections performed significantly better than thesections with conventional mixes In addition the sections with SAMI performed better than thesections without a SAMI Additionally the RAC-O with a SAMI showed the best performance whencompared with the same mixes without a SAMI [2]

Figure 6 Chip Seal

The successful performance of these applications led Caltrans into developing reflectivecracking equivalencies for these applications For example when RAC-G is used as an overlaySAMI-R (ARAMI) is considered to have reflective cracking equivalencies of 15 mm and 30 mm fortreated and untreated bases respectively Also the reflective cracking equivalencies are 30 mmand 45 mm when a conventional DGAC overlay is used for treated and untreated basesrespectively [12] [13]

There has been a number of successful chip seal projects built with terminal blend bindersusing various amounts of rubber content (Hicks et al 2010) [14] In July 2009 Los Angeles Countybuilt its first chip seal project with 18 percent rubber content Prior to this the County built


terminal blend projects with 10 or less rubber content (Hicks and Ryan 2010) [15] Terminalblend binders in chip seal applications have been used in some states with good performance(Hicks et al 2010)

50 Material Properties and Key Specification Parameters

The performance of rubber-modified binders depends on the elastomeric propertieswhich are influenced by the manufacturing process It is important to achieve the required levelof digestion of the rubber in the binder through adequate dispersion to create a rubber-networkor matrix within the asphalt binder The physical aspect of mixing creates a physio-chemicalinteraction between the asphalt and the rubber [2]

Asphalt-Rubber binder is a composite binder consisting of a liquid binder and solid rubberparticles while the Terminal Blend is more homogeneous [16] Table 6 illustrates this conceptfrom extraction tests conducted on both binders Note the extender oil is included in the liquidpart of Asphalt-Rubber

It is difficult to compare the material properties of Asphalt-Rubber and Terminal Blendbinders since the Terminal Blend process has been a moving target in terms of the amount ofrubber added to the binder Terminal Blend performance specifications have been used that canbe met with either a polymer modified asphalt or a combination of CRM and polymer to modifiedasphalt binder (Table 1)

Binder Type Binder Mix Design

DWA

ActualBinder Content

DWA

Liquid Binder(by weight of

mix)

Pounds Liquid in aTon of Mix

MB15-G 71 752 700 140 lbsRAC-G 80 849 626 125 lbsAR4000-D 50 613 578 116 lbsMB4-G (45 mm) 72 777 721 144 lbsMB4-G (90 mm) 72 777 721 144 lbs

MAC15-G 74 755 702 140 lbs

Table 6 Binder Extraction Results [16]


Note recently there have been several efforts that have shown the potential for the developmentof PG grading specification for Asphalt-Rubber with minor equipment modifications

The binder properties for specific Asphalt-Rubber and Terminal Blend binders are shownin Tables 7 8 and 9 along with their project specification limits Both binders were tested at thesame temperature 177ordmC (350ordmF) for comparative purposes The Asphalt-Rubber binder testedcontained PG 58-22 and PG 64-16 base asphalts as shown in Tables 7 and 8 The Terminal Blendbinder tested was PG 76-22 (Table 9) There are some obvious differences as can be seen fromthe tables For example the viscosity values at 177ordmC (350ordmF) were around 400 centipoises forthe Terminal Blend and 1800 to 2700 centipoises for Asphalt-Rubber This shows Terminal Blendto be 5 to 7 times less than the viscosity of Asphalt-Rubber for the binders tested at thistemperature This is a very significant difference This results in lower binder contents for hotmixes and in lower application rates for chip seals The high viscosity of the Asphalt-Rubberbinder allows for increased binder contents in paving applications In hot mix binder contentsbetween 8-10 percent are common and in chip seals an application rate around 25-295 litersm2

(055-065) gallonsq yd is commonly used Terminal Blends have lower optimum bindercontents in the range of 5-6 percent for dense graded mixes and lower application rates around113-225 litersm2 (025-050 galsq yd) for chip seals depending on the aggregate sizeTerminal Blend chip seals commonly use a 95 mm (38 inch) maximum aggregate and requires anapplication rate in the 135-190 litersm2 (030-042 galsq yd) range while Asphalt-Rubber chipseals generally use a 95 mm to 13 mm (38 to frac12 inch) aggregate size with a 25-295 litersm2

(055-065 galsq yd) application rate On the other hand there are some similarities betweenthe two binders in terms of penetration resilience and softening point

It should be mentioned here that the viscosity specification for Terminal Blend binderscan range between 500-1000 centipoises at 135ordmC (275ordmF) (Table 1) lower than the viscosityspecification for Asphalt-Rubber which is in the range of 1500-4000 centipoises at 177ordmF (350ordmF)

Few investigators have conducted studies on the properties of these binders Forexample Thodesen et al evaluated several binders using the multiple creep recovery test [17]Among the binders studied were an Asphalt-Rubber binder and a Terminal Blend binder that uses10 percent CRM and 1 percent SBS polymer The Asphalt-Rubber binder was in accordance withthe Arizona specifications The results showed that the Asphalt-Rubber binder exhibited the leastcreep and the highest percent recoveries under various loading and temperature ranges (Figures7 and 8) The Terminal Blend binder yielded high percent recoveries however it was seen that atthe higher loading rate it did not recover as much as the Asphalt-Rubber For illustration Figure 7


shows the percent recovery at 100 and 3200 Pa at a temperature of 70ordmC As can be seenAsphalt-Rubber exhibited over 160 percent recovery and the Terminal Blend showed over 100percent recovery at the 100 Pa shear stress level Similar trends are shown at the 3200 Pa shearstress level

Test PerformedMinutes of Reaction Specified

Limits60 90 135 360 1440Viscosity Haake at 177degC (350degF)Pa-s

Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000

Resilience at 25degC Rebound(ASTM D3407)

31 32 32 33 31 20 Min

Ring amp Ball Softening Point degC (degF)(ASTM D36)

62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)

Needle Penetration at 4degC (392F)200g 60 sec 110mm(ASTM D5)

35 32 35 33 29 10 Min

Table 7 Asphalt-Rubber Binder Properties over Time (Using PG 58-22 Base Asphalt)



Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)

Needle Penetration at 4degC 200g 60sec 110mm(ASTM D5)

30 31 31 31 30 10 Min

Table 9 Terminal Blend PG 76-22TR Binder Properties over Time

6 Discussion

Strategies utilizing Asphalt-Rubber and Terminal Blend binders have shown betterperformance when compared with strategies that utilize conventional asphalt bindersRubberized asphalt binders have shown improvements over conventional binders Based on casestudies and laboratory tests Asphalt-Rubber exceeds Terminal Blends in terms of itsperformance However two studies have shown the two products to be equal where air voidscould be considered confounding factors Fatigue models on conventional mixes with neatbinders have shown that the influence of air voids on fatigue life to be significant Therefore it isessential that the effect of air voids on fatigue life be investigated and quantified for mixescontaining rubber products

Asphalt-Rubber has a longer history than Terminal Blend since it started over 35 yearsago Asphalt-Rubber and Terminal Blend are distinctly different binders and have been used invarious types of mixes and seal coat applications When it comes to hot mixes one of the best


uses for Terminal Blends is in dense graded asphalt concrete (DGAC) whereas Asphalt-Rubber isbest utilized in RAC-G and RAC-O This is because the gap gradation and open gradation allowspace for the Asphalt-Rubber particles However Terminal blend binders have been used in gapgraded and open graded mixes Asphalt-Rubber should not be used in dense graded mixes sincethe rubber particles can create a compaction problem because the space requirements for theparticles are not there Moreover the lower viscosity of Terminal Blends results in lower optimumbinder contents in hot mixes that translates into less performance life

Surface chip seals and interlayers have been performing successfully using Asphalt-Rubber Additionally there has been a number of successful chip seal projects with terminal blendbinders Terminal Blendsrsquo history in this area has not been long enough to provide acomprehensive understanding of its performance However the lower viscosity of TerminalBlend binders results in lower application rates than if the higher viscosity of Asphalt-Rubberbinder is used The lower application rates mean less binder per unit indicating less performancelife than if Asphalt-Rubber is used The ability to inject more binder in the mix translates to betterfatigue and reflective cracking performance

Figure 7 Percent recovery at 100 and 3200 Pa at 70ordm C [17]


Figure 8 Percent recovery versus temperature [17]

As shown in this paper each of these two binders has been shown to have it unique propertiesand performance It is important to consider key factors affecting performance such as binderproperties and binder contents or application rates Combining these factors together produces apositive compounding effect on the performance

The need to react or swell the CRM in asphalt binders has been widely accepted andspecifications have included a minimum reaction time for Asphalt-Rubber It has been thoughtthat the Asphalt-Rubber particles would swell during the reaction time by absorbing the maltenewhich acts as release capsules over time resulting in enhanced aging properties for the Asphalt-Rubber binder On the other hand the Terminal Blend binders are made by heating the binder foran extended period at high temperatures that result in dissolving the rubber particles

Terminal Blend technology has been evolving The effect of heating the binder over timehas not been clearly understood yet The questions that remain to be answered include 1) Dothe binder properties degrade as a result of the extended heating over time 2) Does the meltingof the rubber particle enhance the properties and performance of the binder 3) How well can the


amount of rubber be determined in the binder 4) How important is the solubility requirement inthe specifications

7 Conclusions

It can be concluded that Asphalt-Rubber and Terminal Blend are distinctly different bindersThe two binders are not equal or equivalent materials The following are some of the conclusionsthat can be derived from this paper

The two technologies have been successful in incorporating recycled waste tires in variouspavement strategies

Two studies have shown the performance of the two products to be similar where airvoids could be considered confounding factors Other performance tests have shownAsphalt-Rubber to have better performance than Terminal Blend

Both binders provide improvements in the performance of pavement strategies overstrategies that use conventional asphalt cement

The two binders have different specification requirements and each provides its uniqueperformance characteristics Asphalt Rubber has a long established and consistentspecification utilizing the same ingredient components Terminal Blend specificationscontinue to evolve and change with little laboratory or field data to determine the effectsuch changes

The viscosity of Terminal Blend is much lower than the viscosity of Asphalt-Rubberresulting in much lower application rates and binder contents which translate into lessfatigue and reflective cracking resistance Higher viscosity in Asphalt-Rubber relates togreater film thickness which provides extended service life performance

Asphalt Rubber has a long performance history in chip seals interlayers and gap gradedmixes Terminal Blend has less performance history concerning chip seals interlayersand gap graded mixes

The Terminal Blend binder has adopted the PG grading system Recent efforts haveshown that the Asphalt-Rubber binder can also be PG graded with minor equipmentmodifications

Through the PG grading system the Terminal Blend binder specifications may be met witha polymer modified binder


Asphalt rubber binder is best utilized in gap graded and open graded mixes It should notbe used in dense graded mixes

Terminal Blend binder is best utilized in dense graded mixes but has been used in gapgraded and open graded mixes

8 References

[1] ASTM 2005 ASTM International Annual Book of Standards D 8 Definitions 2005

[2] Shatnawi S and Holleran G 2003 ldquoAsphalt-Rubber Maintenance Treatments inCaliforniardquo Proceedings of AR2003 Conference Brasilia Brazil 2003

[3] PCASS 2008 Pacific Coast Conference for Asphalt Specifications Portland Oregon May2008

[4] Shirley E 1992 ldquoDesign Guide for ARHM-GGrdquo Memorandum California Department ofTransportation Feb 28

[5] Caltrans 2003 2006 ldquoAsphalt Rubber Usage Guiderdquo California Department ofTransportation Sacramento CA

[6] MTAG 2003 and 2006 California Pavement Preservation Center California StateUniversity Chico web linkhttpwwwecstcsuchicoeducp2cLibraryCaltrans_Documentshtml

[7] Qi X Shenoy A Al-Khateeb G Arnold T Gibson N Youtcheff J and Harman T2006 ldquoLaboratory Characterization and Full-Scale Accelerated Performance Testing ofCrumb Rubber Asphalt and other Modified Asphalt Systemsrdquo Proceedings of AR2006Conference Palm Springs 2006

[8] Bejarano M Jones D Morton B and Scheffy C 2005 ldquoReflective Cracking Study InitialConstruction Phase 1 HVS Testing and Overlay Constructionrdquo University of CaliforniaPavement Research Center Report UCPRC-RR-2005-03 October 2005

[9] Steven B Jones D Harvey J 2007 ldquoReflective Cracking Study First Level Report on theRutting Experimentrdquo Univresity of California Pavement Research Center ReportUCPRC-RR-2007-06 April 2007


[10] Jones D Harvey J and Monismith C 2007 ldquoReflective Cracking Study SummaryReportrdquo University of California Pavement Research Center Report UCPRC-SR-2007-01 December 2007

[11] Cook M Bressette T Holikatti S Zhou H and Hick RG 2006 ldquoLaboratoryEvaluation of Asphalt-Rubber Modified Mixesrdquo Proceedings of AR2006 ConferencePalm Springs 2006

[12] Caltrans 2001 ldquoFlexible Pavement Rehabilitation Manualrdquohttpwwwdocstoccomdocs20280255FLEXIBLE-PAVEMENT-REHABILITATION-MANUAL June 2001

[13] Caltrans 2009 ldquoHighway Design Manualrdquo web linkhttpwwwdotcagovhqoppdhdmpdfenglishchp0630pdf July 2009

[14] Hicks RG Cheng D Duffy T 2010 ldquoEvaluation of Terminal Blend Rubberized Asphaltin Paving Applicationsrdquo California Pavement Preservation Center Report NumberCP2C-2010-102TM Chico California May 2010

[15] Ryan J Hicks G 2010 ldquoPavement Preservation Journalrdquo Published for FP2 Incsummer 2010

[16] Carlson D Memo on MB HVS Summary UCPRC-SR-2007-01 to Phil Stolarski datedAugust 15 2008

[17] Thodesen C Biro S and Kay J 2009 ldquoEvaluation of Current Modified Asphalt BindersUsing the Multiple Stress Creep Recovery Testrdquo Proceedings of AR2009 ConferenceNanjing China 2009


1 Introduction

This paper discusses the two processes used to incorporate recycled tire rubber in hot mixasphalt and seal coats These two processes are distinct and produce two completely differentbinders namely Asphalt-Rubber and Terminal Blend (Figures 1 and 2) Each of these binders hasits own properties and unique applications

The utilization of crumb rubber modifier (CRM) in asphalt mixtures is intended to improvethe properties of binder by reducing the binderrsquos inherent temperature susceptibility Theaddition of rubber into the binder increases the elasticity and resilience of the binder It improvesthe durability and resistance to fatigue and reflective cracking in hot mixes and chip sealapplications There are environmental benefits to the utilization of the tire rubber in asphaltpavements and diverting this hazardous waste from landfills

11 Asphalt-Rubber

Asphalt-Rubber (Figure 1) has been known historically as the ldquowet processrdquo and has beensuccessfully utilized for over 35 years in Arizona California and other states It is defined by ASTMas ldquoA blend of asphalt binder reclaimed tire rubber and certain additives in which the rubbercomponent is at least 15 percent by weight of the total blend and has reacted in the hot asphaltbinder sufficiently to cause swelling of the rubber particlesrdquo [1]

Asphalt-Rubber is a non-homogeneous composite consisting of liquid asphalt and rubbersolid particles It is believed that during the interaction with asphalt binder the CRM particles inasphalt-rubber absorb a portion of the oils in asphalt binder and the particles swell thereforeincreasing the viscosity and stiffness of the CRM binder

There are two types of asphalt-rubber binder Type I and II Type I is mainly used inArizona and Texas It contains asphalt binder and 18 to 20 percent tire rubber that meet a specificgradation requirement Type II is used in California and consists of about 20 percent rubber (75percent ground tire rubber with a suitable grading and 25 percent natural rubber also with asuitable grading) In addition heavy aromatic oils (asphalt modifier) may be added up to 6percent Type I and Type II binders are used internationally The asphalt-rubber binder is blendedusing a low shear system for a minimum of 45 minutes [2]





2 Strategies




SpecificationGrade



Maximum PasD 4402

30 30Dynamic Shear


D 717564100

76100


D 2872100 100



D 717564220

76220


D 6084 Method B2575

2565


D 6521100 110



D 7175225000

315000


D 6648-183000300

-123000300








PreviousCaltrans


ARFC RHMA-O-HB
















4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References























2 Strategies




SpecificationGrade



Maximum PasD 4402

30 30Dynamic Shear


D 717564100

76100


D 2872100 100



D 717564220

76220


D 6084 Method B2575

2565


D 6521100 110



D 7175225000

315000


D 6648-183000300

-123000300








PreviousCaltrans


ARFC RHMA-O-HB
















4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References




















SpecificationGrade



Maximum PasD 4402

30 30Dynamic Shear


D 717564100

76100


D 2872100 100



D 717564220

76220


D 6084 Method B2575

2565


D 6521100 110



D 7175225000

315000


D 6648-183000300

-123000300








PreviousCaltrans


ARFC RHMA-O-HB
















4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References























PreviousCaltrans


ARFC RHMA-O-HB
















4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References































4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References






















4 Case Studies













MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References



























MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References























MAC15 74 MAC15 63MB15 71 MB15 62MB4 72 MB4 64



MAC15 755 MAC15 49MB15 752 MB15 51MB4 777 MB4 65





















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References





































Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References































Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References




























Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References






















Figure 6 Chip Seal










DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References


























DWA


DWA


mix)



MAC15-G 74 755 702 140 lbs













Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References






























Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References























Centipoise cP

18 21 23 24 27 15-401800 2100 2300 2400 2700 1500-4000


31 32 32 33 31 20 Min


62(144)

63(145)

64(147)

63(146)

64(148)

55 min(131Min)


35 32 35 33 29 10 Min




Centipoise cP

20 22 23 24 21 15-402000 2200 2300 2400 2100 1500-4000


37 - 40 - 38 25 Min


67(153)

- 68(154)

- 66(151)

57 min(135 Min)


28 - 30 - 31 10 Min





Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References






















Centipoise cP

040 040 040 038 038 15-40400 400 400 380 380 1500-4000


32 31 29 30 31 25 Min


87(189)

87(189)

87(189)

87(189)

87(189)

57 min(135 min)


30 31 31 31 30 10 Min


6 Discussion














7 Conclusions













8 References






























7 Conclusions













8 References


























7 Conclusions













8 References





















7 Conclusions













8 References






















8 References




























Date post:	12-Aug-2020
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