Poster

Laboratory Evaluation of Plant Compacted High RAP Sections in New Hampshire
Graduate Researcher : Ashton Congalton, B.S., University of New Hampshire, agp24@unh.edu
Advisor: Dr. Jo Sias Daniel, Ph.D., P.E., University of New Hampshire
Results:
Research Objective:
• To evaluate the performance of plant produced RAP mixes in
terms of low temperature cracking, stiffness, and permanent
deformation
• To determine the impact of bumping binder grade at higher RAP
percentages on material properties
Materials:
• Six plant produced RAP mixtures supplied by the Pike Industries
Northfield NH Asphalt Plant with same target gradation, 12.5mm
NMAS
• Loose mix sampled at the plant and compacted in FHWA Mobile
Asphalt Pavement Mixture Laboratory without reheating and with
target 7% air void content
% RAP
0%
15%
25%
25%
30%
40%
% Total Asphalt Content
5.9
5.8
5.8
5.8
5.8
5.8
Virgin PG
58-28 58-28 58-28 52-34 52-34 52-34
VMA
16.8
16.9
16.7
16.5
16.4
17.0
VFA
74.0
74.2
75.3
79.0
78.1
75.2
Testing and Analysis:
• All testing was completed by the FHWA Mobile Asphalt
Pavement Mixture Laboratory
• Dynamic modulus and flow number testing was performed on an
AMPT machine following AASHTO TP-62 specifications
• Critical cracking temperature testing was performed following
AASHTO T314
• Binder shear modulus testing was performed following AASHTO
T315
• Multiple Stress Creep Recovery (MSCR) testing performed
following AASHTO MP 19
• Continuous performance grade was found following AASHTO
M320
• Two-tailed t-tests analysis for dynamic modulus and phase angle
raw data
• RHEA software used in mater curve construction
Conclusions:
• Binder bumping only effects high temperature performance
because there is a statistical difference in mixture stiffness
between the two 25% RAP mixes
• Dynamic modulus master curves show an average stiffness
increase for RAP mixtures
• Dynamic modulus blackspace shows that at higher stiffness
values the phase converges. At low stiffness the PG 58-28
mixes were more viscous then the PG 52-34 mixes.
• Shear modulus blackspace shows that at all stiffness values the
PG 58-28 mixes were more viscous than the PG 52-34 mixes.
• With increased RAP there is an increase in flow point at 600 kPa
with the exception of PG 52-34 30% RAP mixture.
• With increased RAP between 15% and 40% there is a
decreasing trend in critical cracking temperature.
• MSCR testing shows that as you increase add RAP in the virgin
binder the temperature at which each grade (S,H,V,E) is met
increases as well. PG 52-34 with 25% RAP gave the largest
temperature value for each grade excluding the 100% RAP
binder.
Ongoing and Future Work:
• Fatigue testing and analysis on reheated laboratory compacted
mix , plant compacted mix and cores using the S-VECD approach
• Dynamic Modulus testing on reheated laboratory compacted mix,
plant compacted mix and cores using the AMPT
MSCR Test Results
Acknowledgements:
• All material was donated by PIKE Industries Inc.
• Matt Corrigan and the FHWA Mobile Asphalt Pavement Mixture
Laboratory
• FHWA and NHDOT provided funding
• Advisor Dr. Jo Sias Daniel
• Geoff Rowe at Abatech
PG 58-28
PG 52-34
15% RAP
PG 58-28
25% RAP
PG 58-28
25% RAP
PG 52-34
30% RAP
PG 52-34
40% RAP
100% RAP
PG 52-34
Standard Traffic "S" Grade Temp (C)
58
54.8
59.5
59.9
65.2
61.5
60.5
82
Heavy Traffic "H" Grade Temp (C)
53.2
51.5
54.5
54.9
60.3
54.5
55.5
76.7
Very Heavy Traffic "V" Grade Temp (C)
48.8
47
50
50.5
56
50.2
50
72