Aggregate interlock behavior of large crack width concrete joints in PCC airport pavements

A major drawback to the use of aggregate interlock joints in pavements constructed with Portland Cement Concrete (PCC) lies in the inability of the engineer to predict the behavior and performance of such joints through the service life of the pavement. This inability can result in designs that may lead to increased stresses and deflections in the pavement and subsequently fatigue failure of the pavement and a shortened service life. Available monotonic and cyclic load analytical models have two primary limitations. First, they are based on the test results for joints with a maximum crack width of around 0.03 inch. Field measurements of joint widths of PCC pavements show crack widths as large as 0.08 inch at the pavement surface. Second, these models were developed for low cycle, high intensity, loadings. PCC pavements typically are subjected to high cycle, low intensity, loadings. The number of cycles of loading during the service life of an airfield pavement may reach hundreds of thousands, or even millions.; The primary objective of this research program was to study the behavior of one type of aggregate interlock joint of large crack width subjected to monotonic and cyclic loadings. Other types of joints were investigated experimentally for comparison purposes.; A total of thirty-seven bench top tests were conducted. The experimental results indicate that crack width, aggregate type and gradation are the major factors influencing behavior. The surface roughness characteristics for all the joint types tested were successfully measured using digital image analysis. An analytical model for predicting the monotonic and cyclic behavior of the river gravel joint of large crack width is developed. An significant finding from this study is that it is unlikely that fatigue failure of an aggregate interlock joint will occur during the service life of the airport pavement for the specific type of joint tested, even for a crack width as large as 0.08 inch.