Use of glass waste as granular material in pavement layers

Abstract

The valorisation of waste glass is part of a sustainable development plan. It presents several challenges, starting with the elimination of the various types of waste sent to landfill and the related costs, the reduction of the inconveniences associated with glass (shards, landfill fires), the development of new economic sectors and raw material saving (aggregate quarries). Several research works have previously been carried out to highlight the interest of using waste glass as a partial replacement for unbound granular aggregate in pavement structure. Nevertheless, industrialists remain reluctant to apply such a technique, which encourages researchers to extend their studies in order to properly control the behaviour of granular materials containing glass grains and consequently give more confidence to companies to enforce this technical solution. The present work consists in studying the influence of the shape of glass grains less than 5 mm (rounded and sub-rounded) on the mechanical behaviour of granular pavement materials. The study consists in making a comparison, from a behaviour point of view, between the two forms of glass grains obtained from two different grinding processes. As a result, the Proctor test clearly shows that there is no significant difference between rounded and sub-rounded shape in terms of compactabiliy. It was noted that the addition of particles of recycled glass makes the mixture more insensitive to water. It has been also found that the limiting percentage of addition of glass particles is situated between 20% and 30% reported to the total mass of the mixture.