Experimental investigation on physical properties and early-stage strength of ultrafine fly ash-based geopolymer grouting material

Abstract

The conventional cement grouting materials possess certain drawbacks that hinder their environmental compatibility. The utilization of geopolymer grouting materials with the raw material of fly ash is anticipated to serve as a proficient approach in mitigating the environmental problem caused by solid wastes. Consequently, this study employed ultrafine fly ash (UFA) and granulated blast furnace slag (GBFS) as composite base materials to fabricate a kind of novel geopolymer grouting material. The addition of 0.05 % − 0.2 wt% graphene oxide (GO) facilitated the preparation of this material, and the physical properties and early-stage strength were experimentally investigated. The micro-analysis was conducted using micro-analysis techniques, including Fourier transform infrared and energy dispersive X-ray spectroscopy, etc. The findings indicated that as the contents of GO and GBFS increased, the flowability slightly decreased; the addition of GBFS and GO can contribute to the elevation of viscosity; the initial and final setting times were decreased. The bleeding rate decreased and increased with increasing GO and GBFS contents. It was also found that the GO and GBFS were beneficial to increase the water retention rate. Furthermore, the inclusion of GO and GBFS significantly enhanced the early-stage compressive strength of the grouting material. The GO and GBFS contents of 0.1 % and 60 % resulted in the attainment of maximum compressive strength of samples, with the value of 15.89 MPa at the first day. The simultaneous utilization of GO and GBFS facilitates the generation of a greater quantity of calcium-alumina-silicate-hydrate gel, thereby substantially enhancing the initial compressive strength of grouting materials. The results of this study could provide valuable perceptions into the production of sustainable grouting materials with low carbon emissions and the recycling utilization of solid wastes.