The role of waste glass powder in alkali-silica reaction mitigation: Transforming glasscrete durability through chemical composition dynamics

The alkali-silica reaction poses a significant challenge to the durability of concrete structures, primarily due to the reaction between alkaline pore solutions and reactive silica in aggregate, generating hygroscopic gel that leads to cracks and concrete deterioration in the presence of moisture. Waste glass powder is selected due to its high silica content, pozzolanic reactivity, and potential to bind alkalis, which can mitigate ASR-induced expansion. Additionally, its use promotes sustainability by reducing cement consumption and repurposing industrial waste, aligning with the principles of green construction. Utilizing waste materials in optimal dosage offers sustainable concrete with balanced durability and performance. In this study, models were generated to predict alkali-silica reaction (ASR). Expansion for concrete modified with waste glass as cement replacement, such as linear, pure quadratic, and M5P-tree models based on the chemical composition of glass and cement, and other input parameters such as w/b, cement, fine aggregate, glass replacement, and immersion time. The findings indicate that incorporating glass powder effectively reduces expansion (%), with optimal dosages identified through the expansion-time optimizing technique. Comparative assessments reveal that while glass powder demonstrates notable ASR mitigation at lower dosages, fly ash exhibits superior long-term performance across all replacement levels, particularly after 28 days of immersion in NaOH solution. Additionally, slag performs competitively at higher dosages, indicating its potential utility in ASR reduction. Higher SiO₂/CaO ratios lead to reduced ASR expansion, particularly with increased GP (%) and more extended curing periods. Higher GP (%) also results in higher ASR expansion, rising from 0.05 % in plain mortar to 0.2 % with 40 % GP after 3 days. In contrast, plain mortar bars with 0 % GP at a SiO₂/CaO ratio of 0.3 show minimal ASR expansion of 0.03 % after 3 days, rising to 0.18 % after 28 days, indicating the critical role of immersion time in alkaline solutions.