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HOT MIX ASPHALT WITH HIGH RAP CONTENT
Viktors HaritonovsDr. sc. ing., ResearcherMartins ZaumanisDr. sc. ing., ResearcherRolands IzaksPhD, Scientific assistant
1 – 4 September , 2015. Funchal, Madeira, Portugal
1st International Conference on Structural Integrity
1. INTRODUCTION
2. OBJECTIVE
3. MATERIALS AND METHODS
4. RAP PROPERTIES
5. MIX DESIGN
5. RAP DESIGN
6. PERFORMANCE EVALUATION
7. STIFFNESS
8. CONCLUSIONS
CONTENT
ICSI 2015 │Funchal
Due to increasing cost ofasphalt binder, significanteconomic savings can berealized using high content ofreclaimed asphalt pavement(RAP) in the production ofnew hot mix asphalt (HMA).
ICSI 2015 │Funchal
1. INTRODUCTION
The objective of the research is to develop high contentrecycled mixtures using materials found in Latvia inorder to meet the local volumetric and performance -specification requirements for medium and high trafficintensity roads of Latvia and to ensure performance ofthese mixtures similar to virgin asphalt.
ICSI 2015 │Funchal
2. OBJECTIVE
VIRGIN BITUMENTwo types of new bitumen were used. Bitumen 50/70 was used to produce the referencemixture from virgin materials, while for all mixtures having RAP a softer grade bitumen(70/100) was added as rejuvenator
VIRGIN AGGREGATESLocal fractionated and crushed dolomite.
RAP MATERIALSTwo RAP sources were used.The first source of RAP (A7) was millings from a road rehabilitation project, where an upperlayer of an existing pavement was removed. No crushing or screening was done for thismaterial.The second source of RAP (A6) was millings from full-depth road reconstruction project,therefore the resulting RAP was a combination of different asphalt types. Prior to recyclingthis RAP was crushed and fractionated to size 0/11 mm. This was likely the reason for highdust content (16.2 %).
ICSI 2015 │Funchal
3. MATERIALS AND METHODS
RAP source A6 RAP A7 RAPBitumen content, % 5,12 4,9Sieve size, mm passing, %22,4 100 10016 100 99,411,2 96,4 92,48 89,3 57,15,6 81,9 34,44 74,7 26,12 63,8 21,71 52,8 19,30,5 41,3 17,40,25 29,4 14,90,125 20,2 12,50,063 16,2 11,1
Property Test method Unit Requirement B50/70
Requirement B70/100
Virgin binder values Aged binder valuesB50/70 B70/100 A6 RAP A7 RAP
Penetration at 250C EN 1426 0,1 mm 50 -70 70 - 100 64,5 86 38 55
Softening Point R&B EN 1427 0C 46 -54 43 - 51 47 46 59 50
Fraas Breaking point EN 12593 0C ≤ -15 ≤ -15 -17 -20,8 -9 -11
ICSI 2015 │Funchal
4. RAP MATERIAL PROPERTIES
Property Test method Unit Requirement
B50/70
A6 RAP 30% A7 RAP 30% A7 RAP 50%Percentage binder replacement, %
31,8% 36,5% 62,5%Penetration at 250C EN 1426 0,1 mm 50 -70 66 73 65Softening Point R&B EN 1427 0C 46 -54 50 47 49
Fraass Breaking point EN 12593 0C ≤ -15 -16 -18 -16
Blended binder properties
Mix type BinderAsphalt content,
%
Virgin asphalt content, %
Percentage binder
replacement, %
V, % VMA, % VFB, %
Required value2,5–6,5 ≥14 ≤80
AC-16 base/bin 50/70 4,7 4,7 0,0 4,5 15,6 71,5A6 RAP 30% 70/100 3,96 2,7 31,8 6,8 16,1 57,7A7 RAP 30% 70/100 4,25 2,7 36,5 5,5 15,5 64,4A7 RAP 50% 70/100 4,26 1,6 62,5 4,5 14,7 69,1
Asphalt mixture properties
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5. MIX DESIGN
Resistance to rutting
Roller compactor
Stiffness and fatigue
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6. PERFORMANCE EVALUATION (1)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
0 2500 5000 7500 10000 12500 15000 17500 20000
Rut
dep
th i
n m
m
Crossings
AC 16 base/bin A6 RAP 30 % A7 RAP 30 % A7 RAP 50 %
1 Cycle = 2 Crossings
Rutting
The obtained results demonstrate that the largest average rut depth of 3.4 mm and wheel tracking slope of 0.15 mm/1000 cycles appear for the AC-16base/bin references mixture
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6. PERFORMANCE EVALUATION (2)
Fatigue
4550556065707580859095
100
0 40000 80000 120000 160000 200000 240000
Stiff
ness
loss
, % (i
nitia
l)
Load cycle
T=100C; 10Hz; 115µm/m
AC16base/bin A6 RAP 30 % A7 RAP 30 % A7 RAP 50 %
4550556065707580859095
100
0 40000 80000 120000 160000 200000 240000
Stiff
ness
loss
, % (i
nitia
l)
Load cycle
T=100C; 10Hz; 130µm/m
AC16base/bin A6 RAP 30 % A7 RAP 30 % A7 RAP 50 %
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6. PERFORMANCE EVALUATION (3)
12224,9 10487,4
8814,5
11558,1
0,02000,04000,06000,08000,010000,012000,014000,0
Stiff
ness
(Mpa
)
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7. STIFFNESS
The aim from the design process was to produce recycled mixes with similarproperties to the reference mix AC16base/bin (virgin mix made using bitumenB50/70).
1. RAP has no significant effect on volumetric and mechanical properties of therecycled HMA in terms of Marshall stability and flow as well as rut resistance.
2. Test results demonstrated that mixtures with RAP showed a little higher resistanceto rutting compared to reference mixture.
3. All recycled mixtures (except the A7 RAP 50%) compered to reference mixtureshowed similar fatigue resistance.
4. The use of RAP, especially high RAP content, in HMA decreased the fatigueresistance.
5. Based on the findings of this study it can be concluded that it is possible to designhigh-quality HMA with up to 50% RAP that meets the desired volumetric andperformance requirements
ICSI 2015 │Funchal
8. CONCLUSIONS
Thank You!
Questions?
1st International Conference on Structural Integrity
1 – 4 September , 2015. Funchal, Madeira, Portugal
Viktors HaritonovsDr. sc. ing., Researcher
