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by
Dr. Mohammad Nahid SiddiquiProf. Mohammad Farhat Ali
&Eng. Mirza Ghouse Baig
Department of Chemistry
King Fahd University of Petroleum & Minerals
Dhahran, 31261
Saudi Arabia
To Study the effects of To Study the effects of antistripping agents on asphalt-antistripping agents on asphalt-aggregate mixtures using aggregate mixtures using Adsorption-desorption and IR test Adsorption-desorption and IR test methodsmethods..
Introduction and BackgroundIntroduction and Background Moisture DamageMoisture Damage Anti-Stripping AdditivesAnti-Stripping Additives
ExperimentalExperimental Asphalt & Aggregate PropertiesAsphalt & Aggregate Properties Adsorption-desorption Testing Adsorption-desorption Testing
Results and DiscussionResults and Discussion ConclusionsConclusions
Moisture DamageMoisture Damage
SignificanceSignificance: :
A A high degree of strippinghigh degree of stripping was was
detected in detected in between 25 to 50%between 25 to 50% on on
various pavement sites inspected various pavement sites inspected
in Saudi Arabia during late 1990.in Saudi Arabia during late 1990.
Moisture DamageMoisture Damage
Main FocusMain Focus: :
To Improve To Improve aggregate aggregate asphalt bonding.asphalt bonding.
Antistripping AdditivesAntistripping Additives
Organic Small MoleculesOrganic Small Molecules Amines, SilanesAmines, Silanes Polyamines, AmidoaminesPolyamines, Amidoamines
Inorganic Aggregate TreatmentsInorganic Aggregate Treatments Hydrated LimeHydrated Lime Portland CementPortland Cement
Polymeric AgentsPolymeric Agents Functionalized ButadieneFunctionalized Butadiene Styrene-ButadieneStyrene-Butadiene
• Asphalt-aggregate interactions in pavements
directly affect the adhesion & bond strength.
• Chemistry of asphalt & surface chemistry of
aggregates particularly affects the interactions.
Asphalt-Aggregate BondingAsphalt-Aggregate Bonding
* *WettabilityWettability
* *Viscosity (temp)Viscosity (temp)
* *Composition Composition (oxygen)(oxygen)
* *DurabilityDurability
**Surface chemistry Surface chemistry (mineral (mineral composition)composition)
* *Surface textureSurface texture
* *PorosityPorosity
* *Surface condition Surface condition (cleanliness, (cleanliness, moisture)moisture)
Asphalt Aggregate
Effect of Surface Film on Aggregate Coverage (after Hubbard)
Effect of Aggregate Surface on Texture Adhesion (after Hubbard)
Contact Angle in an Aggregate, Asphalt and Water System (after pfeiffer).
Effect of Polarity on Adhesion
(after Hubbard)
Molecular Orientation
(after Hubbard)
• Asphalts from Two Refineries• Riyadh Refinery (RY)
• Ras Tanura Refinery (RT)
• Aggregates from Three different regions• Taif
• Eastern Province (EP)• Riyadh
• Three Anti-Stripping Agents• Iterlene IN/400-S• Cecabase 260• Polyram L200
Elemental Analysis (wt %) of RT and RY Asphalts
ElementsSample IDRT RY
C
H
S
N
O
H/C
O/C (x10-3)
S/C (x10-2)
N/C (x10-3)
Asphaltenes %
Ni
V
V/Ni
84.66
10.41
4.58
0.39
Nil
1.46
Nil
2.03
3.96
33
114
3.45
84.25
10.14
4.99
0.41
0.21
1.43
1.87
2.22
4.19
27
97
3.59
Physical Characteristics of RT and RY Asphalts
TEST RT RY
Specific Gravity 1.020 1.028
Penetration @ 25°C 57.2 53.2
Penetration @ 4°C 31 22
Softening Point, °C 50.50 50.00
Flash Point, °C 308 325
Ductility, cm 120.83 150+
Sliding Plate Viscosity @ 25°C, Pa.s 88091.9 93744.5
Absolute Viscosity @ 60°C, Poise 3252.51 2695.82
Rotational Viscosity @ 135°C, cP.s 463 494
Kinematic Viscosity @ 135°C, cst 464.39 479.56
Asphalt Grade (WASHO Classification) AR-8000 AR-8000
Aggregates
1. Limestone (Eastern Province)
2. Basalt (granite) (Western Province, TAIF)
3. Limestone (Riyadh Area)
Properties Riyadh (RN) Taif (WP) Dammam (EP)
Aggregate Type Lime stone Basalt (granite) Lime stone
ASTMC-131L.A.Abrasion,%loss 26.4 22.5 32.2
ASTMC-88 Soundness, %loss 6.3 5.24 7.83
C-127 Bulk Specific Gravity of Coarse Aggregate
2.598 2.841 2.587
C-128 Bulk Specific Gravity of Fine Aggregate
2.427 2.709 2.436
Specific Gravity of Mineral Filler 2.672 2.783 2.621 D-2419 Sand Equivalent 53 68 48
Plasticity Index NP NP NP
% Absorption of FA C-128 or
CA C-127
1.1 0.7 2.1
Properties of Aggregates
Anti-Stripping Agents
S.NoS.NoProduct NameProduct Name Physical Physical
StateState
Recommended Recommended Dosage (wt %)Dosage (wt %)
StabilityStability Chemical NameChemical Name Flash Flash PointPoint
11 ITERLENE ITERLENE IN/400-SIN/400-S
LiquidLiquid 0.2 - 0.40.2 - 0.4 Heat Heat Stable Stable (170(170oo C)C)
Alkylamido-Alkylamido-imidazoimidazo
PolyaminePolyamine
>180>180oo
CC
22 CECABASE CECABASE 260260
LiquidLiquid 0.2 - 0.40.2 - 0.4 Heat Heat StableStable
Alkylamido-Alkylamido-imidazoimidazo
PolyaminePolyamine
>100>100oo
CC
33 POLYRAM POLYRAM L200L200
LiquidLiquid 0.2 - 0.40.2 - 0.4 Heat Heat StableStable
N-Alkyl ‘tallow’ N-Alkyl ‘tallow’ dipropylene dipropylene triaminetriamine
>100>100oo
CC
Chromatography Column
Adsorption Equation
Ai = [VC (A1 – A2)]/50 A1
where,
Ai = initial adsorption, mg/gm
V = volume of solution in the column at the
time A2 is measured, ml = 00.0 ml
C = initial concentration of asphalt in solution,
gm/l = 1.2 g/l
A1 = first absorbance reading
A2 = second absorbance reading after 6.5 hours
Results & Discussion:
Initial and Net Adsorption Values for Riyadh
Asphalt with Cesabase-260Mass of Asphalt
(gm)Asphalt
Solution g/L
Initial Adsorption Ai (mg/g)
Net Adsorption An (mg/g)
%Differenc
e between Ai
and An
A1 A2 A3
Taif 0.12 0.63 0.606 0.62 1.2 0.036 0.015 58.75E.P. 0.124 0.71 0.68 0.695 1.24 0.052 0.026 50.51
Riyadh 0.123 0.72 0.69 0.71 1.23 0.052 0.017 67
AggregateAbsorbance
Results:
Mass of Asphalt
(gm)Asphalt
Solution g/L
Initial Adsorption Ai
(mg/g)
Net Adsorption An (mg/g)
%Difference between Ai and
An
A1 A2 A3
Taif 0.124 0.7 0.69 0.695 1.24 0.017 0.008 50.51E.P. 0.129 0.792 0.765 0.78 1.29 0.054 0.024 56
Riyadh 0.121 0.675 0.656 0.665 1.21 0.03 0.016 47.9
AggregateAbsorbance
(Cont’d)
Initial and Net Adsorption Values for Ras-Tanura Asphalt with
Cesabase-260
Results:
Mass of Asphalt
(gm)Asphalt
Solution g/L
Initial Adsorption Ai
(mg/g)
Net Adsorption An (mg/g)
%Difference between Ai and
An
A1 A2 A3
Taif 0.114 0.85 0.81 0.845 1.14 0.076 0.009 87.63E.P. 0.11 0.785 0.765 0.774 1.1 0.034 0.018 45.56
Riyadh 0.114 0.74 0.715 0.732 1.14 0.041 0.013 68.32
AggregateAbsorbance
(Cont’d)
Initial and Net Adsorption Values for Ras-Tanura Asphalt with
Iterlene 400-S
Results:
Typical Comparison on Riyadh asphalt-aggregate mix
(Cont’d)
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
% a
sph
alt
rem
ain
ed
adso
bed
Taif E.P. Riyadh
Aggregates
Figure 1: Effect of Antistipping agent in adsorption behavior of Riyadh asphalt-aggregate mixtures
Asphalt Riyadh
Cesabase-260
Iterlene IN/400-S
Polyram L200
Results:
Typical Comparison on Ras Tanura asphalt-aggregate mix
(Cont’d)
0.010.020.0
30.040.050.060.070.0
80.090.0
% a
sph
alt
rem
ain
ed
adso
rbed
Taif E.P. Riyadh
Aggregates
Figure 2: Effects of Antistripping agent on Ras Tanura asphalt-aggregate mixtures
Asphalt Ras Tanura
Cesabase-260
Iterlene IN/400-S
Polyram L200
Based on the results of this study Based on the results of this study following conclusions were drawn.following conclusions were drawn.
Type of Aggregates has significant Type of Aggregates has significant effect on absorption behavior.effect on absorption behavior.
Different aggregate showed different Different aggregate showed different adsorption for same asphalt.adsorption for same asphalt.
Moisture sensitivity for each asphalt-Moisture sensitivity for each asphalt-aggregate combinations depend on the aggregate combinations depend on the type of antistripping agent used. type of antistripping agent used.
No single antistripping agent could work No single antistripping agent could work with all three aggregate types studied. with all three aggregate types studied. Therefore, selection of proper Therefore, selection of proper antistripping agent will be unique for antistripping agent will be unique for each project.each project.
Among the three antistripping agents Among the three antistripping agents studiedstudied Cecabase was found to be more effective Cecabase was found to be more effective
with Riyadh asphalt mixtures. with Riyadh asphalt mixtures. Iterlene was found to be more effective with Iterlene was found to be more effective with
Ras Tanura asphalt mixtures Ras Tanura asphalt mixtures
(Cont’d)
More fundamental work is needed on More fundamental work is needed on the chemistry of asphalt-aggregate the chemistry of asphalt-aggregate interaction for a better understanding interaction for a better understanding of the chemical compositional factors of the chemical compositional factors that control asphalt properties..that control asphalt properties..