An evaluation of the effect of crushed waste glass on the performance of cold bituminous emulsion mixtures

Abstract

Large quantities of waste glass are generated each year, as municipal solid waste, and disposed of. There are industries who could make use of this product, specifically road pavement manufacturers. The current technology for paving roads will soon become financially unsustainable because of the rapid and continuous growth of community transportation. To address this issue, this study aims to evaluate the effect of replacing local virgin aggregates with crushed waste glass has similar gradation of virgin fine aggregate with 2.36 mm Nominal Maximum Aggregate Size (NMAZ). Four replacement percentages were assessed, namely 25%, 50%, 75% and 100% from virgin fine limestone aggregates content in Cold Bituminous Emulsion Mixtures (CBEM), as CBEM technology has several environmental, sustainable and economic advantages over HMA. The test protocol involved the evaluation of the mechanical properties of CBEM’s in terms of the Marshall Test, Indirect tensile strength (ITS), wheel track test (WTT) and dynamic stability (DS) properties. Moisture damage, in respect of Retained Marshall Stability (RMS), was also evaluated for the modified mixes. The test results show that the addition of crushed glass (up to 100%) as a fine aggregate, resulted in a new CBEM with mechanical and durability properties higher than traditional HMA. While slight reductions in mechanical and durability properties were noted when compared with untreated CBEM, it was still within local specification limits of the Iraqi General Specifications for Roads and Bridges, (GSRB). In term of mechanical and durability performance, it was concluded that the new mixture (CBEM-100%FGA) can be used as a structural surface layer for heavily trafficked loading conditions. It is necessary however, to note that the new mix still has high air void contents.