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

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• 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

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• 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!