Grain-scale insights into crushed waste glass as a sustainable fine aggregate

Abstract With growing interest in repurposing glass waste for construction applications, this study presents a comprehensive grain-scale characterisation of crushed waste glass (CWG) as a synthetic fine aggregate, benchmarked against both natural and manufactured sands. A suite of size-independent physicochemical properties was systematically evaluated to define CWG’s intrinsic material behaviour. CWG exhibited an impervious and amorphous structure inherited from glass manufacturing, resulting in a negligible saturated surface-dry moisture content ( $$\approx$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>≈</mml:mo> </mml:math> 0.04%), reduced wettability with contact angles of 45−50° (significantly higher than conventional fine aggregates, $$p &lt; 0.05$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&lt;</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> </mml:math> ), comparable mechanical performance and an irregular, angular morphology. Thermogravimetric analysis demonstrated superior thermal stability, with less than 0.5% mass loss at 950 °C, compared with approximately 1% for natural sand and 3% for manufactured sand observed in this study. Complementary macro-scale tests assessed inter-particle friction, aggregate interlocking and moisture retention, providing additional insight into CWG’s behaviour in granular assemblies. The findings highlight CWG’s potential as an active and sustainable alternative to conventional fine aggregates in construction materials.