Influence of pumice on mechanical properties and durability of high performance concrete

Abstract

High performance concrete (HPC) which combines Portland cement and other natural and artificial pozzolans mainly aims to extend the service life of concrete structures in harsh environments. Recently, volcanic pumice pozzolan (VPP) has been effectively used to enhance the performance of HPC. VPP is a natural environment friendly material of volcanic origin and it is found abundantly in western parts of the USA. This study explored thirty-seven various concrete mixtures, which includes ordinary Portland cement (OPC) and other binary and ternary mixtures integrating the ultrafine VPP as a major supplementary cementitious material (SCM) along with other cementitious materials namely fly ash, slag, silica fume and metakaolin. The research was conducted to evaluate two performance parameters namely the compressive strength and the durability due to chloride-induced corrosion. Two different non-destructive testing instruments, namely 4-point Wenner Probe and Merlin meter were utilized to investigate the surface resistivity (SR), the bulk resistivity (BR) and the charge passed within a very short time. These are important hardened concrete properties related to the corrosion resistance of reinforced concrete structures. The results indicated that the binary and ternary-based VPP mixtures have remarkably higher compressive strength and very low permeability compared to OPC and other SCM based binary mixtures from early ages to long-term period (up to 91 days). Further, the results showed the compressive strength has a strong correlation with SR and BR over long period. Overall, the ternary VPP based mixtures revealed promising outcomes by means of strength and corrosion resistance and possible implementation in future reinforced concrete bridges.