presentation at create@state - 2015
TRANSCRIPT
A M Feroze RashidGraduate StudentCollege of Engineering
Investigation of Low Temperature Cracking and Fatigue Resistance of Asphalt Concretes with Reclaimed
Asphalt Pavement (RAP)
Faculty Mentor:Dr. Zahid HossainAssistant Professor of Civil Engineering
Arkansas State University
This presentation will be forwarded as
• Introduction• Problem Statement• Significance• Objectives• Methodology• Test sites
• Relevant Studies• Concluding Remarks• Future work plan• Acknowledgements
Outline
Arkansas State University
• RAP => Green technology
Introduction
• Usages of RAP in USA
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• South central states (TX, OK, AR, LA, MI, TN) are facing extreme low temperatures and diurnal temperature changes as well
• RAP is very brittle • RAP mix and blends are susceptible to low temperature
cracking and fatigue damages
Problem Statement
Thermal Crack Fatigue Crack
Arkansas State University
• Although it weakens pavement, RAP usage introduces economic and sustainable road construction
• Existing test methods have some limitations to characterize RAP mixed asphalts
• Proper test methods to predict the RAP mixed asphalt concrete behavior will safeguard this green engineering
Significance
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• Bending Beam Rheometer (BBR) Test– Does not measure material strength– Time consuming process– Does not consider mineral-binder interaction
• Thermal Stress Restrained Specimen Test (TSRST)– Rate of change of temperature might not field representative– Sensitive apparatus setup, constant coolant supply– Time consuming test procedure
• Double Edged Notch Test (DENT)– Specialized costly equipment and extensive effort
Limitations of Existing Practices
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• Review relevant literature and case studies• Evaluate low temperature and fatigue cracking
properties of asphalts modified with RAP• Improve resistance to aforementioned
distresses by using rejuvenator• Develop a simple test method to characterize
aforementioned properties
Objectives
MethodologySurveying for Existing Pavement Performance
Collect RAP core
Extraction & Recovery
Rheological Property Determination
RV DSR BBR
BBR Pro(A new methodology)
Field Calibration
Documentation in AASHTO format
Computer Programming
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• Up to 40% RAP in base and 10% in surface course
• Reported increase in fatigue resistance
• Excess RAP than ODOT specification can be used
Relevant Studies
• DSR test is not suitable to measure fatigue behavior of RAP
• Fatigue life is dependent on loading rate and frequency
• Direct Tension Test, X-Ray and Numerical Analysis• Removes shortcomings of DSR Test• Reports fine fillers to improve binder fatigue
resistance
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• 4 RAP samples will be evaluated in 2 years• Sites for the first year are:
RAP Sites of the Current Study
(Good Performing)
(Poor Performing)
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Historical Weather Data
History of weather at Forest City (starting and ending of road work)
History of weather at Alma (starting and ending of road work)
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Historical Traffic Data
Figure: Traffic Data for Good Section at Forest City and Poor section at Alma
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Extraction & Recovery
Field Core Oven Loose RAP Solution Extractor
RAP Binder
OvenRotaVaporAsphalt + Solution Asphalt in flask
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• RAPs are viable paving materials• Higher RAPs => lower permanent
deformation• Rejuvenator is expected to increase
fatigue resistance
Concluding Remarks
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• Test other binders with other RAP– Low temperature strength – Modification of time consuming BBR Test
• Evaluation of Chemical additives as rejuvenators– Allow higher RAP content
Future Work
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• Arkansas State Highway & Transportation Department (AHTD)
• Southern Plains Transportation Center (SPTC) and • Office of Research and Technology Transfer of Arkansas State University
Acknowledgements
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Thank you all
Any Questions!