A comprehensive review on compressive strength and microstructure properties of GGBS-based geopolymer binder systems

The demand for sustainable binders has been globally encouraged owing to the alarming carbon emission levels associated with conventional cement production. Geopolymer binders are the most cost-effective, and sustainable engineered alternatives that provides the scope for the development of several binder systems made out of aluminosilicate wastes thereby contributing toward a clean environment. Next to fly ash, the second most widely used source material for geopolymerization is ground granulated blast furnace slag (GGBS) which offers several benefits such as high early age strength and excellent durability properties under low curing temperatures. In this context, this review article firstly describes the significance of different chemical oxide compositions namely: SiO2, Al2O3, CaO, Fe2O3, and MgO, present in GGBS during geopolymerization. Thereafter, the article discusses the compressive and microstructure properties of various GGBS-based geopolymer binder systems (paste, mortar and concrete) made with fly ash (FA), red mud (RM), and ferrochrome ash (FCA) – as some of the contemporary industrial wastes. The microstructure properties, such as x-ray diffraction (XRD), scanning electron microscope (SEM), and fourier transform infrared spectroscopy (FTIR) are taken into consideration to validate the reaction products, morphology, and bond arrangements, respectively. From this study, it is revealed that blending GGBS with aforementioned aluminosilicate wastes in suitable proportion delivers the viable sustainable option for potential applications in the construction industry thus reducing the dependence on conventional cement. [Display omitted] •GGBS-based geopolymer binder systems provide an eco-friendly alternative to traditional cement-based systems.•The chemical oxides present in GGBS govern the formation of geopolymer network inside the matrix.•Compressive strength development is mainly dependent on the effectiveness and quantity of C-A-S-H gels.•CaO in GGBBS provides the matrix stability by generation of calcium-based geopolymer gels.•Microstructure aspects are controlled by the curing conditions, choice of source materials, and type of aluminosilicate gels.