Mechanistic-Based Model for Predicting Reflective Cracking in Asphalt Concrete–Overlaid Pavements

One of the most common types of pavement on the national highway system is composite asphalt concrete (AC) over portland cement concrete (PCC). With a large percentage of PCC pavements either approaching or at the end of their design lives, AC overlay of PCC pavements has become one of the most common methods of rehabilitation. This has resulted in several thousand kilometers of composite AC/PCC pavements. As the level of heavy truck traffic loading continues to increase on a majority of pavements, it is likely that the total length of composite pavements in the nation will continue to increase considerably in the coming years. A common type of distress that occurs on these composite pavements is reflective cracking. This occurs when the joints or cracks in the underlying PCC pavement reflect through the AC overlay. A performance model that can be used to predict accurately the amount of reflective cracks in composite AC/PCC pavements has enormous potential uses. The development of a mechanistic-based performance model for predicting the amount of reflective cracks in composite AC/PCC pavements is described. Data from the Long-Term Pavement Performance database were used to develop the model. Using the principles of fracture mechanics, it is illustrated that a mechanistic-based model can be developed that closely models the real-life behavior of composite pavements and predicts the amount of reflective cracks. Because of the mechanistic nature of the model, it is particularly effective for performance prediction for design checks and pavement management. Also, since the model can take into account the relative damaging effect of the actual axle loads in any traffic distribution, it has great potential for application in cost allocation.