Occurrence and impacts of hollow space under a continuously reinforced concrete pavement

Transverse cracks are common in continuously reinforced concrete pavement (CRCP) surfaces and would not impair smooth-riding experiences of vehicles once they are kept tight by longitudinal steels. However, these cracks are vulnerable spots for the occurrence of hollow space underneath, starting from water invasion of existing cracks and traffic loading. Longitudinal cracks developed over a hollow space may lead to punchout, the limit failure of a CRCP. In this paper, efforts have been made to identify possible locations and shapes of hollow space and explore the impacts of hollow spaces. These efforts consist of finite element analysis to evaluate distributions of maximum tensile stresses and vertical deflections within CRCP surfaces that imply hollow space development, and comparisons to current design standards in China neglecting the existence and impacts of hollow space. It is concluded that surface slab corners are not only the most possible locations for hollow space occurrences, but also critical loading positions that lead to maximum tensile stresses and vertical deflections. Sizes of hollow spaces and other parameters such as surface slab thickness are important factors to distributions of tensile stresses and vertical deflections. It is more rational to take the existence of a hollow space into account during CRCP structure design processes.