Features of road pavement reinforcement technology with cement concrete layers

Abstract

Whitetopping overlay is a concrete overlay on the prepared existing hot mix asphalt (HMA) pavement to improve both the structural and functional capability. It's a relatively new rehabilitation technology for deteriorated HMA. If the slab thickness is less or equal to 4 in., it is referred to as ultra-thin whitetopping (UTW). "WT" is used to refer to concrete overlay thicker than 4 in. In this research, the term "whitetopping" is used to refer to both WT and UTW in general. The primary objectives of this study are to catalog the whitetopping (WT) and UTW projects in Wisconsin, document pertinent design and construction elements, assess performance and estimate a service life of these projects. A comprehensive literature review was performed. A database of the WT and UTW projects was established covering 18 projects built from 1995 to 2007 in Wisconsin. The performance of these WT and UWT projects were assessed, by mean of shear strength tests on field cores, falling weight deflectometer (FWD) tests on selected projects, and field distress survey on in-service projects. FWD backcalculation methods for WT and UTW pavements were studied and a Critical Distance Method was proposed and utilized for UTW pavement. Fatigue life was analyzed using 18kip, 22kip and 26kip single axle load level. Performance assessment was conducted using both Pavement Condition Index (PCI) and Pavement Distress Index (PDI). The performance of whitetopping projects in Wisconsin was found comparable to that in other states. Whitetopping overlay thickness, joint spacing and pavement age were found to have significant effects on pavement performance.