Recycling waste glass powder in lightweight aggregate concrete: Towards lightweight, sustainable and durable marine engineering structures

The feasibility of recycling waste glass powder (GP) as a sustainable supplementary cementitious material (SCM) to enhance the durability and corrosion resistance of structural lightweight aggregate concrete (SLAC) was investigated in this study. The effects of GP substitution on the fresh, mechanical, and durability properties of SLAC were systematically examined. Microstructural analyses of the matrix pore structure and aggregate-matrix interface were conducted to elucidate the mechanisms behind the improved durability and corrosion resistance of GP-modified SLAC. The results show that GP incorporation reduces mechanical strength, including compressive strength and splitting tensile strength, with greater reductions at higher GP substitution levels. However, with extended curing age, strength differences among mixtures narrow significantly. GP incorporation also enhances the elastic modulus at later curing stages (90 days). Additionally, GP refines the matrix pore structure and densifies the aggregate-matrix interface, thereby enhancing chloride resistance and electrical resistivity while reducing capillary water absorption. During the drying-wetting cycles, GP-modified reinforcement specimens exhibited more positive open-circuit potential values, indicating improved corrosion resistance of steel reinforcement in chloride-rich environments. These findings demonstrate the feasibility of recycling waste GP to improve the sustainability and durability of SLAC, offering promising prospects for lightweight marine engineering structures.