Development of Reflective Cracking Model for Airport Asphalt Overlay Design

Abstract: Reflective cracking in asphalt concrete (AC) overlays on existing jointed concrete pavements is considered a major pavement distress. The movement of the PCC slabs below the overlay due to the combination of thermal and traffic loading leads to reflective crack growth through the AC overlay. The Federal Aviation Administration’s (FAA) current pavement design program, FAARFIELD, does not consider thermal loading and joint reflective cracking. This study presents the development of a fracture mechanics-based model to predict reflective cracking in pavements. By incorporating advanced 3-D fracture simulations, computationally efficient algorithms, and consideration of asphalt's viscoelastic behavior, the models effectively capture the effects of aircraft traffic and thermal loading on crack propagation. The elastic-viscoelastic correspondence principle is utilized to calculate viscoelastic energy release rate to determine crack propagation using a modified Paris Law. Reflective crack propagation algorithms are developed for thermal and aircraft loading scenarios, considering pavement temperature prediction, PCC joint movement, and aircraft moving load. Numerical models are developed and simplified to capture the effect of AC-PCC interaction on the magnitude of joint opening in a computationally efficient manner. Furthermore, A moving load and wander algorithm is introduced to efficiently simulate non-uniform crack propagation due to traffic loading. Case studies demonstrate the model's ability to predict fatigue life under various climate and loading conditions, highlighting the significant influence of viscoelastic properties and climate on crack propagation rate.