Durability of alumina silicate concrete based on slag/fly-ash blends against acid and chloride environments

Abstract

The durability of a concrete mainly depends on its resistance against acid and chloride environments. This article presents an investigation of the durability of geopolymer concrete with GBFS (Granulated Blast Furnace slag), Fly ash (class F) and alkaline activators when exposed to 5 % sulphuric acid and chloride solutions. GBFS was replaced by fly ash with different replacement levels from 0 % to 50 % in a constant concentration of 12-M alkaline activator solution. The main parameters of this study are the evaluation of the change in weight, strength and microstructural changes. The degradation was studied using Scanning Electron Microscopy (SEM) with EDAX. From the test results it is observed that the strength of the geopolymer concrete with GBFS in ambient curing performs compared well to geopolymer concrete with GBFS blended with fly ash. The acid resistance in terms of the rate of reduction of strength of GPC with GBFS is 85 %, while for 40 % replacement of fly ash to GBFS performs well with a reduction of only 53 %. Similar observations are also observed in a chloride environment in which 40 % replacement of fly ash to GBFS performs well when compared to GPC with GBFS. Hence, geopolymer concrete with 40 % replacement of fly ash for GBFS is the appropriate level of replacement, satisfying the above durability properties.