Effects of coarse aggregate surface morphology on aggregate-mortar interface strength and mechanical properties of concrete

Coarse aggregate surface textures have a significant effect on mechanical properties of aggregate-mortar interface in normal strength concrete. The authors used a scanning microscope to scan the surface of aggregates in concrete to observe surface morphology. The results showed that the surface morphology components of coarse aggregates were varying at different scanning scales, which included waviness and roughness. Each component was quantitatively characterized. New methods to calculate the interfacial tensile strength and shear strength considering the influence of 3D surface morphology were proposed. The methods were introduced into a 3D meso-numerical model. Uniaxial compression and direct tension tests were conducted to examine the effects of coarse aggregate surface morphology (CASM) on the mechanical behaviors of concrete. Compared to the test results, the numerical model can well predict the failure procedure of concrete and the cracking characteristics of interface with different aggregate surface morphologies. Moreover, it was found that concrete tensile strength was more sensitive to CASM than compressive strength. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study demonstrated that the surface morphology of coarse aggregates significantly affects the mechanical properties of concrete, including components such as waviness and roughness. New calculation methods considering the influence of 3D surface morphology accurately predict the failure procedure of concrete and interface cracking characteristics. Additionally, it was found that tensile strength is more sensitive to coarse aggregate surface morphology.