Reflective Cracking Model for Airport Asphalt Overlay Design

AC Overlay Design for Airfield Pavements

Reflective cracking in hot-mix asphalt (HMA) laid over existing jointed concrete airfield and highway pavements is considered as a major pavement distress. Reflective cracking mechanisms are complex due to intertwined effects of temperature and vehicular loading conditions causing intensified stresses in overlays. FAA’s structural design guidelines for overlays do not consider reflective cracking. Therefore, there is a need to develop fundamental fracture-based design models for airfield HMA overlays that can be incorporated in FAA’s pavement design software FAARFIELD.

Application of Advanced Numerical Modeling Approaches

The proposed research approach consists of developing advanced 3-D fracture simulations to capture the reflective cracking mechanism occurring in airfield pavements. Field data will be collected to simulate actual conditions that resulted in various cracking severity and extent. Input data include pavement structure, materials, climate, and aircraft loading and passes. To ensure computational efficiency, numerical fracture simulation results will be utilized in artificial neural network models to predict energy-based crack driving forces. Field data will be used to calibrate reflective cracking models.

Development of a Mechanistic-Empirical AC Overlay Design Method for FAARFIELD

The main goal of the proposed work is to develop an HMA overlay thickness design model considering reflective crack growth. To achieve this goal utilizing fracture mechanics principles, reflective cracking density and severity model will be developed and used as a decision criterion in the cumulative damage factor (CDF) currently part of the FAARFIELD.