The potential use of crushed waste glass as a sustainable alternative to natural and manufactured sand in geotechnical applications. (15th February 2021) - Kazmi, Danish
Abstract: The increasing price and diminishing reserves of construction sand encourage a need to develop its sustainable and cost-effective replacement, helping the transition towards a circular economy. Waste glass is a derivative of natural sand and could potentially show similar geotechnical behaviour. Using crushed waste glass (CWG) as an alternative to traditional sand would potentially offer a double-duty benefit by helping to address the geo-environmental challenges of natural sand depletion and disposal of ever-increasing waste glass, together. This study investigated the geotechnical, mineralogical and morphological behaviour of CWG and compared it with that of natural sand (NS) and manufactured sand (MS). The geotechnical characterisation results showed that the behaviour of CWG is similar to the other two sands studied, with CWG showing the highest permeability and abrasion resistance. Surprisingly, the shear strength testing showed that the friction angle of CWG was higher under saturated conditions than under dry conditions, indicating the stability of CWG under saturated conditions. The mineralogical analysis was conducted using x-ray fluorescence (XRF) spectroscopy and revealed that silica is the dominant mineral in all three materials, indicating a similarity in their chemical composition. The morphological analysis was performed to quantify the particle shape of each material in terms of roundness index using digital images obtained through an optical microscope. The results demonstrated that MS showed the highest particle angularity, followed by CWG and NS. Overall, it was concluded that CWG could potentially act as a next-generation alternative and smart geomaterial, replacing traditional sands in several geotechnical applications. Video Abstract: The authors in this video abstract present the key motivations, analyses performed, and conclusions of cross-institutional research published in the Journal of Cleaner Production (JCR: Q1, SJR: Q1, 2019 journal impact factor: 7.2, ranked number# 1 worldwide in Sustainable Development according to Google Scholar metrics at the time of this article publication). This research investigated the potential use of ever-increasing waste glass as a sustainable alternative to depleting natural and manufactured sand in geotechnical construction. The study compared the geotechnical, mineralogical and morphological behaviour of crushed waste glass with that of two traditional types of construction sand. The findings showed that the geotechnical behaviour of crushed waste glass is similar, or sometimes even superior, to traditional construction sands. Overall, it was concluded that crushed waste glass could potentially serve as an alternative and smart geomaterial, ultimately promoting the recycling of waste glass, reducing the burden on landfill and conserving natural resources, all helping the transition towards a circular economy. youtube link: https://youtu.be/pGVoJ1QYWUA Highlights: Crushed waste glass showed geotechnical behaviour similar to traditional sands. The friction angle of crushed waste glass increased under saturated conditions. XRF spectroscopy showed that silica is the dominant mineral in all test materials. Morphological analysis revealed that crushed waste glass has sub-rounded grains. Crushed waste glass could potentially be an alternative and smart geomaterial.