Effect of heat treatment on pozzolanic activity of volcanic pumice used as cementitious material

Volcanic pumice (VP) is a highly vesicular material derived from acidic lavas. It substantially contains amorphous silica, and widely used in many industry, such as construction, textile, chemical and agricultural industries, due to its physical properties. The study is aimed to evaluate the suitability of finely ground (−20 μm) and/or heated (at 1000 °C) volcanic pumice powder to be used as a supplementary cementitious material. Mortar cylinders were prepared using finely ground natural pumice powder, and heated (1000 °C) pumice powder (0-20%) at different mixes ratios as cement replacement. The results from this study showed that the heat treatment significantly affected the pozzolanic activity of VP, and use of heated-ground pumice as a supplementary cementitious material increased the strength of mortar up to 7% in 90 days as well as 7- and, 28-day strengths.