A comparative study on shear strength of crushed waste glass with natural and manufactured sand

This study compares the shear strength behavior of crushed waste glass (CWG) with that of traditionally-used natural and manufactured sand. Direct shear experiments were performed under dry and wet conditions at seven applied normal stresses ranging from 6.8 to 436.0 kPa. The experiments were performed in two series. Firstly, the peak friction angle of the as-received materials was tested. Shear strength testing was then performed on modified materials with a constant maximum particle size of 600 microns, to eliminate the effect of larger particles on the shear strength test results. It was observed that the friction angle of manufactured sand and CWG decreased when their maximum particle size was reduced. Manufactured sand had the highest wet friction angle, followed by CWG and natural sand. Interestingly, it was observed that the friction angle of CWG was higher under wet conditions compared to that under dry conditions, which is contrary to the expected behavior of sands and indicates a relatively superior shear strength behavior of CWG under saturated conditions. Overall, it was concluded that CWG showed friction angles comparable to those of natural and manufactured sand; indicating that CWG could potentially act as an alternative to depleting natural sand in various geotechnical applications, ultimately contributing to the transition towards a circular economy.