Application of recycled glass – crushed rock blends in road pavements

Recycled glass is a mixture of different coloured glass particles with debris. It is the result of crushing the waste glass collected from residential and industrial areas. Construction and Demolition (C&D) materials such as concrete, excavation stone (basalt) and brick make up a significant proportion of the waste materials present in landfills in Australia. Substituting the quarry produced crushed rock with recycled materials in road pavement subbase applications would significantly reduce the demand for landfill sites and would potentially provide an opportunity to use recycled material as aggregates in parts of the state where aggregates sources are becoming scarce. This paper discusses the suitability of using blends of recycled glass and crushed rock as road pavement subbase materials with mixtures of 10% to 50% by mass of recycled glass. The experimental works undertaken in this study includes basic classification tests along with modified compaction, California Bearing Ratio (CBR) and Los Angeles Abrasion tests to assess the suitability of the blends. The research indicates that initially up to 15% “recycled glass with the maximum particle size of 4.75 mm” could be safely added to Class 3 crushed rock. The degree of breakdown occurring in the recycled glass blend is on the limit of what would be acceptable for this material. Depending on the results of future field trials, it may be possible to increase the percentage of recycled glass.