Utilization of copper slag waste in alkali-activated metakaolin pervious concrete

Abstract

This study aims to evaluate the feasibility for preparing alkali-activated metakaolin (AAM) pervious concrete incorporating copper slag (CS) waste. The effects of replacement of metakaolin with CS on the total void ratio, water permeability, mechanical properties, and abrasive resistance of the pervious concretes were investigated. Hydration heat evaluation, SEM, and XRD were conducted to reveal the components interaction. The results showed that the total void ratio and water permeability of the pervious concretes increased with adding CS, since the binder thickness for coating aggregate correspondingly reduced due to the higher density for CS than metakaolin. Although the reactivity of CS was lower than that of metakaolin, the pervious concrete with 30% CS still obtained the comparable compressive and flexural strengths to the concrete without CS. It is mainly attibuted to the strength compensation caused by the CS micro-aggregate effect and a denser microstructure. Adding CS in the concretes obtained a satisfactory abrasive resistance owing to the high paste strength and low wear loss. This study extends the knowledge of using CS in AAM pervious concrete and broadens the CS application scenarios, which is beneficial for consuming CS waste and reducing carbon emissions and costs of pervious concrete preparation.