Partial replacement of low reactive volcanic ash by cassava peel ash in the synthesis of volcanic ash based geopolymer

This study assesses the replacement of low reactive volcanic ash by ashes of an agro-waste matter (cassava peel) within the range of 0-30% by mass in geopolymer synthesis. Gradual replacement of volcanic ash decreases the initial setting time and increases the compressive strength to about 64 and 733% respectively. Also, it turns down the magnitude of efflorescence. After immersion in 5% solution of sulphuric acid, the surface of all specimens remains structurally intact. Cassava peel ash behaves as an additional precursor that brings synergistic effect to volcanic ash during alkaline activation. (C) 2019 Elsevier Ltd. All rights reserved.