Influence of Granulated Silico-Manganese Slag on Compressive Strength and Microstructure of Ambient Cured Alkali-Activated Fly Ash Binder

Abstract

This work focuses on gainful utilization of low reactive fly ash at ambient temperature into alkali-activated binder with the addition of another industrial waste silico-manganese (SiMn) slag. Granulated SiMn slag (GSS) percentage was gradually increased into fly ash-based reference batch. The influence of slag on reactivity of the blends was monitored by isothermal conduction calorimetry. Reactivity was improved with increasing slag content. The structural reorganizations of the resultant binder were detected by peak shifting in Fourier transform infrared spectroscopy study. The positional change of the hump in X-ray diffraction analysis was due to structural rearrangement of the binder. The calcium-rich hydrated product formation was increased with slag inclusion. The fly ash-derived geopolymer gel (N–A–S–H) was coexisted with slag activated gel (C–S–H/C–A–S–H), (where N = Na2O, A = Al2O3, C = CaO, S = SiO2, and H = H2O) in the blend matrix. EDX analysis confirmed the variation in Si/Al, Ca/Si, and Na/Al ratios of the binder with the alteration of reaction products. The development of better compressive strength in slag-rich binder attributed with the formation of Ca-rich gel phases.