A study on the bond strength and durability characteristics of high-performance concrete modified with toughened glass waste aggregates

Amidst rising natural aggregate consumption, recycling dumped waste for structural concrete effectively addresses resource scarcity and environmental contamination. Nevertheless, the adoption of toughened glass waste aggregate (TGWA) in construction remains relatively limited. This study explores the potential use of toughened glass waste (TGW) as a substitute for natural coarse aggregate (NCA) in high-performance concrete (HPC). This paper assesses the bond strength of deformed bars embedded in toughened glass waste high-performance concrete (TGW-HPC), considering different steel reinforcement diameters (8 mm and 12 mm) and various levels of TGW replacement (ranging from 0 % to 100 %). Various durability properties, including water absorption, water permeability, chloride ion penetration, and acid attack were examined. The study also investigated the microstructural characteristics of acid attacked specimens using techniques such as XRD, FTIR, and FESEM. Several important parameters, such as chloride diffusivity (D), hydraulic diffusivity (D (θ)), and permeability coefficients (K), were derived from the experimental data. The study found TGW50-HPC resulted in the highest bond strength, about 13.1 % more than the control mix. However, TGW100-HPC bond strength decreased by 17.51 % compared to the control mix. Notably, TGW100-HPC exhibited superior durability properties and showed the lowest coefficient of permeability, indicating reduced chloride ion, and water molecule transport through the interconnected pore structure. At 90 days, the TGW100-HPC mixture exhibited a strength reduction of 42.29 %, which closely resembled the 41.20 % reduction observed at 56 days. The formation of thenardite and basanite mitigate damage to the interfacial transition zone (ITZ) led to fewer micro-cracks and reduced acid ingress through the matrix. Incorporating TGWA in engineering projects can lead to cost savings through reduced raw material expenses and disposal fees, resulting in significant economic benefits and social well-being.