Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes

Abstract

Mechanical strength, water and chloride permeability of alkali activated slag mortar and concretes with partial fly ash substitution are investigated. Volume of permeable voids (VPV) and sorptivity testing show that alkali-activated materials exhibit higher water absorption than OPC-based samples, and increasing fly ash addition leads to reduced mechanical strength and increased water absorption. Conversely, chloride permeability testing by the NordTest NT Build 492 standard accelerated method, and by chloride ponding (ASTM C1543), shows that the diffusion of chloride in alkali-activated binders is much less than in OPC binders. This divergence between measured water uptake and chloride perm..