Effects of calcined perlite powder as a SCM on the strength and permeability of concrete

The use of Supplementary Cementitious Materials (SCMs) has been developed to reduce the environmental pollution and the consumption of precious natural resources in the concrete industries. Furthermore, use of these materials usually reduces the cost and enhances the durability of concrete. Perlite, as a natural glassy volcanic rock, is easily accessible in the most parts of the world; besides, previous studies have demonstrated that Calcined Perlite Powder (CPP) could be used as an effective SCM. However, few studies have investigated the impact of it on different properties of concrete. In this study, the influence of partial replacement of Ordinary Portland Cement (OPC) with CPP on the compressive strength and concrete resistance to chloride ions ingress is investigated. For this purpose, eight different concretes by two w/b ratios and three levels of OPC replacement were cast, cured, and tested at 7, 28 and 91 days. Results reveal that although replacement of OPC with CPP insignificantly decreases the compressive strength of concrete, the permeability is highly improved. Besides, it was known that surface resistivity as a simple non-destructive test, even in concretes containing CPP, could reliably predict the rapid chloride permeability and the migration coefficient of concrete.