Recycled glass powder for enhanced sustainability of limestone calcined clay cement (LC3) mixtures: mechanical properties, hydration, and microstructural analysis

Abstract

The large quantities of nondegradable waste glass led to landfill overflow, causing severe environmental harm. Measures need to be taken to reduce the environmental problems associated with waste glass. Limestone calcined clay cement (LC3) has excellent performance and a low-carbon footprint. However, its environmental benefits still require improvement. This study proposes a strategy to partially replace LC3 with recycled glass powder (RGP) to utilize waste glass while reducing CO2 emissions further. RGP replacement percentages are 10 and 20 %. Experimental studies were systematically conducted to investigate the performance, product composition, and CO2 emission of RGP-LC3. Experimental tests on a macro scale include workability, mechanical properties, and ultrasonic pulse velocity. The composition and microstructure of the material were characterized using thermogravimetric, Fourier-transform infrared, X-ray diffraction, and scanning electron microscopy. The CO2 emissions of LC3 at different stages of its lifecycle were compared and discussed how RGP can reduce these emissions. The results show that RGP helps to increase the workability of the slurry. LC3 containing 10 % RGP showed similar compressive strength to the control group, and 20 % RGP resulted in a decrease in strength. As the replacement percentages increase from 0 to 10 and 20 %, the CO2 emissions per unit volume decrease from 606.46 to 545.14 and 484.43 kg m3/MPa.