Mechanical properties of PVC concrete and mortar modified with silane coupling agents

Abstract

• This study investigated the effect of modification using SCA on the mechanical properties of PVC concrete and mortar. • SCA modification can effectively improve the compressive and flexural strength of concrete and mortar. • SCA can improve the bonding properties between recycled PVC particles and cementitious materials. This study investigates the surface modification of waste polyvinyl chloride (PVC) particles with encapsulated silane coupling agents (SCA) to improve the performance of PVC concrete and mortar. Concrete and mortar were prepared by replacing fine aggregates with equal volumes of PVC particles before and after modification, with volume replacement ratios of 5%, 10%, 15%, 20% and 25%. Experiments were performed to investigate the density, compressive strength and flexural strength of different contents of PVC concrete and mortar. Scanning Electron Microscope (SEM) was used to examine the surface morphology of PVC particles and the interface between the PVC particles and the cementitious material in the mortar. The results showed that the density of concrete and mortar gradually decreased with increasing PVC content; the 28d compressive strength of concrete and mortar increased by 10%-20% after modification with SCA; the 28d flexural strength of concrete and mortar increased by 5%-9%. The SEM results revealed that SCA on the surface of PVC particles improved the mechanical properties of the mortar by better combining the particles with the cementitious material.