Synthesis and characterization of MK /Slag geopolymer composites enhanced by various ratios of nano kaolin

Abstract

Alkaline activation of slag - metakaolin (AAS) binder enhanced with nano-kaolin for preparation of eco-friendly geopolymer materials (40:60 wt. %), of geopolymer binder results in formation of C-A-S-H as well as N-A-S-H gel. Activators used are 10% NaOH solution in addition to 5% liquid sodium silicate both used from the total binder weight), while nano-kaolin was added in the ratio from 0 up to 9% from the total dry weight and replaced the used metakaolin. The properties of the produced geopolymer bricks have been studied through measurement of compressive strength, FTIR, XRD and SEM imaging. Results demonstrate enhancement in both mechanical and microstructural characteristics with nano-kaolin up to 5%, while further increase resulted in agglomeration and strength decrease, also uses of additional activators as sodium aluminate in the ratio of 5% results in strength decline as a results of zeolite increase.