Durability Evaluation: Sustainable Semi-flexible Pavement Mixtures
Saif Hameed Hlail, Shakir Al-Busaltan, Alaa M. Shaban
Abstract
Abstract The modern paving industry requires the production of high-performance pavement using more sustainable approaches. Semi-flexible pavement (SFP), prepared by filling an open-graded asphalt skeleton with cement-based grouting material, has been shown to offer high performance for heavily loaded highway and airport pavement applications. The major aim of this study was therefore to evaluate SFP durability based on more sustainable preparation techniques and materials. In this research, a half warm bitumen emulsion semi-flexible mixture (HWBESFM) was designed using local materials and low energy heating technique; the contribution of various sustainable cementitious grout materials on the durability properties of the mix was then evaluated. The developed grouts were prepared using paper sludge ash (PSA) and silica fume (SF) as supplementary cementitious materials (SCM), and the durability of the HWBESFM was assessed with regard to ageing and water sensitivity. The results showed improvements in water sensitivity of HWBESFM containing OPC+PSA and OPC+SF to 66.62% and 65.73%, respectively, compared with the control mix, which demonstrated sensitivity of roughly 55%. Additionally, slight improvements were noticed in ageing resistance on incorporating SCM, those these results remained uncompetitive to traditional SFP mixtures. Overall, this initial investigation of a sustainable approach could, with some improvement, encourage further development and studies in this area.