Reflective cracking prediction modeling and mitigation strategy for asphalt overlay of airport pavement
Creators: name: Xie, Pengyu
Publisher: name: No Publisher Supplied
Year: 2023

description: Reflective cracking is one of the most common distresses in asphalt overlay. In addition to affecting ride quality, water and foreign debris penetrate through cracks and accelerate the deterioration of pavement performance. The seasonal (thermal) variations and traffic loading are the primary causes of reflective cracking. However, none of the design processes for airfield pavement considers reflective cracking specifically. This dissertation aims to predict reflective cracking growth in asphalt concrete overlay under thermal- and traffic-loading conditions and analyze mitigation strategies for airport pavements. Finite element models were developed to evaluate pavement responses under temperature changes and aircraft tire loading, respectively. For thermal-induced reflective cracking, FE models were developed and validated to predict pavement temperature field and concrete slab movements due to temperature changes. Crack initiation and propagation phases are characterized using the stress-based fatigue model and the modified Paris’ law with J-integral, respectively. For traffic-induced reflective cracking, FE models were developed and validated to predict viscoelastic pavement responses. The load transfer efficiency (LTE) of existing rigid pavement was evaluated under common deterioration scenarios like base erosion and concrete damage. The pseudo J-integral under quasi-static simulation is analyzed considering stress intensity factors (SIFs) of different fracture modes under heavy aircraft tire loading. For thermal induced-reflective cracking, the results show that increasing overlay thickness retards reflective cracking by reducing the movement of concrete slabs and soften asphalt material in cold weather. However, increasing overlay thickness may not lead to proportional reduction of crack potential. On the other hand, the use of soft interlayer moves critical stresses away from the discontinuities of existing rigid pavement and thus retards crack initiation and propagation.For traffic-induced reflective cracking, the results show that increasing overlay thickness by 51mm may lead to the same mitigation effect as applying a 25-mm sand mix interlayer. However, applying interlayer has more benefits in cost-effectiveness and pavement elevation control. Besides, improving load transfer efficiency (LTE) of existing rigid pavement helps control crack growth in asphalt overlay. At the early crack stage, the LTE improvement techniques like dowel bar retrofit or base treatment can dramatically reduce the crack potential by around 40% to 60%. Moreover, an integrated prognostic framework is proposed to improve the accuracy of crack prediction by means of combining physical-based model with field measurement results through Bayesian updating. A surrogate model is proposed to determine J-integral in order to avoid the time-consuming calculation of FE models. A case study is conducted to demonstrate the proposed framework. The results show that the proposed framework can effectively adjust fracture parameters for more accurate prediction of crack propagation, helping with proactive maintenance strategies and reducing the over-design of pavement structures.