Development of Sustainable Cold Rolled Surface Course Asphalt Mixtures Using Waste Fly Ash and Silica Fume

Abstract

The reduction of hot asphalt mixtures for the usage and development of sustainable supplementary cold asphalt mixtures (CAMs) for the construction of road and highway surface layers is a major issue for researchers around the world. This reduction will benefit environmental impact, cost effectiveness, and energy savings. Furthermore, because CAMs comprise a remarkable portion of industrial waste (the disposal of which consumes virgin lands), they are attractive to road and highway authorities. The primary aim of this investigation is to develop new cold rolled asphalt (CRA) with the same gradation as hot rolled asphalt (HRA), which is usually used as a surface course in the U.K., and to improve its mechanical properties and durability by using waste and by-product materials as mineral fillers and additives. Waste fly ash (WFA) was used as a replacement for conventional mineral filler and a by-product silica fume (SF) was used as an additive to enhance the mechanical properties and durability of CRA containing WFA. The experimental results have shown that WFA significantly improves the mechanical properties and durability of CRA. On the other hand, the addition of SF enhances the initial strength, long-term strength, and durability. The new CRA mixture has mechanical properties and durability comparable to those of conventional HRA, which demonstrates the feasibility of the use of CRA in heavy road construction.