Introducing waste glass powder as a sustainable constituent in microsurfacing

This study examines the merits of using waste glass powder (WGP) in a microsurfacing mixture as a replacement for mineral filler. The replacement was done at 0%, 25%, 50%, 75%, and 100% by weight of the mineral filler. The performance of WGP-modified microsurfacing mixtures was evaluated through mix time test, wet cohesion test, wet track abrasion test, loaded wheel test-sand adhesion and loaded wheel test-horizontal and vertical displacement. The toxicity, chemical, and microstructural characteristics were respectively assessed using a toxicity characteristic leaching procedure, Fourier-transform infrared spectroscopy and field emission scanning electron microscopy. Performance analysis of the mixtures showed that an increase in WGP significantly enhanced the mixture's resistance against stripping, bleeding and rutting. The aggregate loss, sand adhesion, horizontal displacement and vertical displacement values at a WGP content of 75% were approximately 62%, 20%, 30% and 36% lower than the values of these parameters at a WGP content of 0%, respectively. Toxicity characteristic leaching tests were performed to compare the extent of heavy metals leaching from stockpiled WGP and from WGP-modified microsurfacing mixtures. It was found that heavy metals leaching from WGP-modified mixtures were 80% lower than heavy metals leaching from stockpiled WGP. The significant reduction in leachate could be attributed to the bitumen covering WGP and preventing WGP particles from exposure to water, as evidenced by microstructural analysis.