Mechanical Properties of Geopolymer Concrete Made with Ground Granulated Blast Furnace Slags and Nanometakaolin

Abstract

Following the concern about environmental pollution, researches have been developed to produce green concrete hence, the development of geopolymer concrete. Many researchers developed geopolymer concrete using unreliable mix design procedures, such as basic mix design methods. In this study, the mix design approach proposed by Reddy et al (2018) was used to create a high strength geopolymer concrete. The current study used nanometakaolin and ground granulated blast furnace slag (GGBS) as solid binders. Geopolymer concrete was made in the laboratory, and its fresh and mechanical properties were studied and compared to equivalent limestone cement-based concrete that served as control samples. The mechanical properties of the slump were examined for workability, splitting tensile strength, flexural strength, and compressive strength. The limestone cement concrete was made with the ACI 211.1 mix design procedure. The experiment's results demonstrated that the created geopolymer concrete had increased workability and mechanical performance. The strength of geopolymer concrete was marginally higher than that of limestone cement concrete when compared to the control samples. The combined polymerization of nanometakaolin and GGBS at ambient temperature resulted in the creation of calium-aluminum-silicate-hydrate (C-A-S-H) and calcium-silicate-hydrate (C-S-H) gels in the concrete mix, which contribute in the strength development of the geopolymer concrete. After 28 days of curing, the geopolymer concrete samples with a 0.20 AAC/BS ratio demonstrated compressive strength, splitting tensile strength, and flexural strength of up to 78.5 MPa, 3.29 MPa, and 15 MPa, respectively. The greatest values found for the reference concrete (cement-based concrete) were 74.33, 2.97, and 11.67 MPa, respectively.