Improvement of Concrete Cracking Resistance and Joint Load Transfer through Coarse Aggregate Selection

Abstract

The ability to transfer load across concrete pavement cracks and the concrete cracking resistance can be improved by careful selection of the concrete constituents, such as the coarse aggregate. The fracture energy from the wedge splitting test was used to represent the cracking resistance of the concrete material, and the power spectral area parameter was used to represent the concrete surface roughness and indicate its ability to transfer load across a crack. Three aggregate types (limestone, river gravel, and trap rock), two aggregate top sizes (25 and 38 mm), and two aggregate gradations (dense and gap gradation) were used in this research to cast six concrete mixes. The experimental results showed that concrete mixes with strong aggregates (i.e., trap rock) had greater cracking resistance and load transfer ability than concrete mixes with weak aggregate (i.e., limestone). Concrete mixes with larger aggregate top sizes (38 mm) had improved mechanical properties relative to smaller aggregate top sizes (25 mm). The aggregate gradation was found to have little effect on the cracking resistance and shear load transfer ability of cracks for 25-mm river gravel aggregates. The wedge split fracture energy test better differentiated the mechanical properties between concrete mixes that contained varying aggregate types and sizes compared with the compressive strength test.