Evaluation of Cracking Behavior of Cold In-Place Recycling Asphalt Mixtures
AuthorCarvajal, Mateo E.
AdvisorSebaaly, Peter E.
Civil and Environmental Engineering
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During the last decades, the asphalt pavement industry has been looking for innovative ways to make its products more environmentally friendly, and recycling methodologies have become widely accepted. According to the National Asphalt Pavement Association, during 2017 construction season, more than 76.2 million tons of RAP were put to use in new pavements in the United States, saving taxpayers more than $2.2 billion. Recycling of the existing deteriorated asphalt pavement offers an attractive approach from the economic and structural standpoint. However, a severely cracked asphalt pavement presents a challenge for the design engineer due to the uncertainty in its cracking behavior and its potential of reflecting the cracks through the new overlay. The Cold In-place Recycling technique has demonstrated effectiveness in delaying the problem of reflective cracking and providing strong base layer, resulting in the requirement of a thinner overlay   .This study evaluated the cracking properties of CIR by means of the Overlay Tester (OT) and the Flexural Beam Fatigue Test. The results indicated that CIR materials have good (low) crack propagation rates but the required energy to initiate a crack is low as well. In addition, some flexibility was observed in the Beam Fatigue Test but a stiff-brittle behavior was predominant. The performance characteristics of the CIR materials were used in a mechanistic analysis to recommend a structural layer coefficient for CIR layer in a flexible pavement structure.