Engineering properties of geopolymer prepared by mild chemical activation of ground granulated blast furnace slag

Abstract

In this research article engineering properties of solely ground granulated blast furnace (GGBS) slag geopolymers have been investigated at varying proportions of alkali activators. Combination of sodium hydroxide (SH) and sodium meta silicate (SMS) powder has been used as alkali activators. Consistency, setting time and compressive strength have been determined at different concentration of SH and ratio of SMS/SH for GGBS geopolymer. Maximum compressive strength of 87.76 MPa has been achieved at 2 molar concentration of SH and SMS/SH = 2.0 after 28 days of curing at ambient temperature. The consistency of mix attaining maximum compressive strength is 27.5%. The initial and final setting time of 55 and 105 minutes has been observed. The soundness of geopolymer paste is within permissible limits. The micro-structural analysis of GGBS and geopolymer paste has been performed by XRD, FTIR, FESEM and EDAX. The co-existence of calcium silicate hydrate gel and geopolymeric gel may be responsible for achieving high compressive strength at low concentration of activators under ambient temperature curing.