Effects of Aggregate Size and Glass Powder Fineness on the Performance and Durability of Self-Compacting Concrete with Recycled Laminated Glass

The sustainability of recycled glass in concrete closely depends on the ability to mitigate the alkali-silica reaction (ASR), a significant challenge stemming from the chemical incompatibility between glass and cement. This study investigates the effects of recycled laminated glass particle sizes on the dimensional stability, mechanical properties, and durability of self-compacting concrete (SCC) under ASR-promoting conditions. Three aggregate sizes (3/8, 8/12.5, and 8/16 mm) and two levels of glass powder fineness were incorporated into SCC mixes and cured for 365 days in baths at 38°C, with and without NaOH in the mixing water. Additionally, mortar specimens were treated in an autoclave at 127 ± 2°C to evaluate dimensional variations. The results highlight the importance of particle sizes and glass powder fineness. Microstructural analyses (XRD, TGA/DTA, and SEM/EDX) revealed significant pozzolanic activity of the finer glass powder, reducing calcium hydroxide content and promoting C-S-H gel formation with lower Ca/Si ratios. High-fineness glass powder also showed notable benefits in improving compressive strength and reducing permeability, enhancing the concrete's ability to limit chloride ion diffusion. Conversely, larger glass aggregates (8/16 mm) caused more significant expansion than smaller aggregates (8/12.5 mm).