Development of a mechanistic-empirical prediction model for joint spalling distress in concrete pavements

Joint spalling has been a typical distress problem in concrete pavements and an open research interest to many pavement engineers. However, most prediction models for joint spalling distress are developed only based on empirical observations from the field and the accuracy of the empirical models has been a question because there is a lack of mechanistic investigation to understand the detail mechanism. In this paper, a reliable spalling prediction model was developed on the basis of shear mechanism under both traffic loads and thermal curling. According to the concept of shear mechanism, the finite element method (FEM) is applied to analyze the numerical responses of pavement structure. A three-dimensional FE pavement model is developed based on the field section information obtained from Korean long-term pavement performance (LTPP) program. The principle shear stress obtained from FE analysis is accumulated at specific pavement age to evaluate its impact on the formation and the growth of joint spalling. A mechanistic-empirical (M-E) spalling prediction model is developed by relating the shear stress accumulation (SSA) to the filed performance of spalling. The proposed M-E prediction model is verified by using various field data from Korean LTPP to indicate its applicability to predict the spalling distress.