Study on processability, compressive strength, drying shrinkage and evolution mechanisms of microstructures of alkali-activated slag-glass powder cementitious material

Abstract

Energy shortage and environmental pollution have become two global problems to be solved urgently. Therefore, it is urgent to develop a low-carbon building material to replace the traditional Portland cement. Alkali-activated materials (AAM) have become a hot topic because they provide many attractive engineering and environmental benefits. In this study, 15 AAMs were developed based on slag-waste glass powder. The setting time, fluidity, compressive strength, and drying shrinkage of AAM were tested. The effects of retarder, water-to-binder ratio, Na2O content, and the modulus of water glass were considered. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Differential thermal gravity-thermal gravity (DTG-TG), and Scanning electron microscope (SEM) techniques were used to reveal the action mechanism of influencing factors on various properties of AAM. Based on the grey entropy theory, the effects of Na2O content and the modulus of water glass on the setting time, fluidity, compressive strength and drying shrinkage of AAM were discussed. The economic and environmental benefits of AAM were evaluated in terms of cost, energy consumption, and carbon footprint. The results show that the prepared AAM shows unexpected results in various properties. In addition, compared with Portland cement, the energy consumption of AAM can be reduced by up to 65.16%, the cost can be reduced by up to 32.88%, and the carbon footprint can be reduced by up to 64.72%. This study not only solves the resource utilization of solid waste glass and slag, but also promotes the application of AAM in engineering.