Mechanical and microstructural properties of alkali-activated slag and slag plus fly ash mortars exposed to high temperature

In this study, changes in the mechanical and microstructural properties of alkali-activated blast furnace slag (BFS) and BFS + fly ash (FA) blended mortars exposed to 25, 400, 600 and 800 degrees C temperatures are investigated. The alkali-activated mortars using the replacement ratios of 0, 25 and 50% FA by weight of BFS together with the activators are produced in addition to the control mortars produced by only cement. Three different optimum Ms (SiO2/Na2O ratio of activators) values of 0.50, 0.75 and 1.00 are determined for the alkali-activated mortars. The FA substitution by BFS increases the high temperature resistance of alkali-activated BFS mortars. (C) 2019 Elsevier Ltd. All rights reserved.