Investigation of drying shrinkage effects on sloped concrete-concrete composites

Abstract

Multi-layer concrete systems have been widely used in bridge decks, rigid pavements, and floors. The restrained drying shrinkage of the overlay is of great concern as it can lead to overlay cracking and/or interfacial debonding. In such constructions, a transverse slope is typically considered to drain off the surface water. Despite advances made in understanding the drying shrinkage of non-sloped concrete-concrete composites, there are still standing questions regarding the overlay cracking, as well as bond failure, in sloped concrete-concrete composites. The current study establishes a high-fidelity computational model validated with experimental tests to evaluate the structural performance of sloped, double-layer overlay systems under drying shrinkage. The simulation scenarios systematically cover the effects of key overlay properties and interface conditions.The numerical analysis results reveal the critical role of overlay thickness and mechanical properties in the time of overlay cracking and interfacial debonding failures. Based on the obtained results, the implementation of a cross slope may delay the failures, depending on the initial thickness. Higher interfacial stiffness also induces stronger restraint against overlay shrinkage strain, leading to a faster overlay cracking.