National Concrete Pavement Technology Center

Project description

The distresses observed lately in thick CRCP sections in Texas are quite different from typical distress types that have long been recognized in CRCP – namely punchouts and spalling. The new distress type is characterized by segmentation of slabs at transverse cracks, generally under the wheel paths. Forensic investigations conducted to identify the cause(s) of those distresses indicate delamination of the slab at the depth of longitudinal steel. It appears that thicker slabs with longitudinal steel placed at mid-depth of the slab result in longer transverse crack spacing, which increases warping stresses. The increased warping stresses in concrete induce horizontal cracking at the steel depth, and wheel loading applications in this area cause segmentation of the upper half of concrete slabs, resulting in serious distresses. This project will investigate the mechanism of this distress type, and develop optimum steel designs. The investigation will consist of evaluating structural responses of CRCP through theoretical analyses as well as field experiments where various steel designs (different steel depths for one-mat and configurations for two-mat) are employed. The results of data analyses from both mechanistic analyses and field experiments will be used to develop optimum steel designs in CRCP.