Stability and Rheological Properties of Grouts with Waste Glass Powder as Cement Replacement: Influences of Content...

Effective recycling and utilization of waste glass is a critical issue that urgently needs to be addressed. This study aims to explore the feasibility of using ground waste glass powder (particle size ≤ 75 μm) as a supplementary cementitious material to partially replace cement in the preparation of low-carbon and environmentally friendly grouting materials. The research systematically evaluates the impact of waste glass powder (WGP) on the fresh properties (particularly the stability and rheological characteristics) of cement-based grouting materials under various conditions, including WGP content (0-40%), the addition of NaOH activator (Na₂O content of 4%) or not, and water-solid ratio (w/s = 0.5, 0.65, 0.8, 1.0). The results indicate that, in the absence of activator, the addition of WGP generally increases the amount of free liquid exudation in the grout, reducing its stability; however, under low w/s ratios, appropriate amounts of WGP can enhance stability. When the w/s ratio is high and the WGP content is large, the grout stability decreases significantly. The addition of NaOH activator (Na₂O content of 4%) significantly reduces free liquid exudation, enhancing the stability of the grout, especially when the w/s ratio is less than 1.0. Furthermore, the Herschel-Bulkley Model was experimentally validated to accurately describe the rheological behavior of waste glass-cement slurries, with all R² values exceeding 0.99. WGP and alkaline activator have significant effects on the rheological properties of the grout. Although they do not change its flow pattern, they significantly affect shear stress and viscosity. The viscosity of the slurry is influenced by the combined effects of w/s ratio, WGP content, and alkaline activator, with complex interactions among the three. The application of these research findings in the field of grouting engineering not only contributes to significantly reducing glass waste but also promotes the production of sustainable cement-based composites, lowering carbon dioxide emissions by reducing cement usage, and thereby alleviating environmental burdens.