Pozzolanic characteristics of silica recovered from olivine: Fid-Bau Portal

Pozzolanic characteristics of silica recovered from olivine

Shah, Vineet / Scott, Allan

Highlights • Use of recovered silica from olivine as a supplementary cementitious material. • Increased early age hydration of cement. • Improved mechanical and durability properties of mortar with recovered silica as compared to silica fume and fly ash. • Reduction in the environmental impact associated with the use of Portland cement.

Abstract Olivine is one of the most abundant minerals on the earth’s surface. In this study, silica was recovered from olivine through an acid digestion process and its applicability as supplementary cementitious material in cement was investigated. Cement pastes and mortar specimens were cast at cement replacement levels of 5, 10, 15 and 30% with recovered silica (RS). Isothermal calorimetry, XRD and TGA were used to analyze the hydration characteristics while the hardened mortar binder properties were assessed using compressive strength, porosity and resistivity. The performance of RS mixes was compared with equivalent silica fume and fly ash mixes. The recovered silica provided both filler and pozzolanic effect from an early age. Better or similar compressive strength as compared to PC was obtained at all the replacement levels and all the ages. The recovered silica from olivine helps in improving the binder properties along with providing potential significant environmental benefits.