Review of sustainability, pretreatment, and engineering considerations of asphalt modifiers from the industrial solid wastes

The escalating mass of solid waste at an overwhelming sum requires a global attention to strive for efficient waste management and to outsource the ecological treatments. The asphalt pavement industry that consumes a vast scale of natural resources while contributing to thermal and greenhouse emissions is viewed as a high potential alternative for the application of solid waste as asphalt modifier and substantial waste reduction. In efforts to urge for cleaner and greener asphalt production, a growing trend towards usage of solid waste as a renewable material is paving a sustainable future for the asphalt pavement industry. The economic options of incorporating solid waste into the asphaltic mixture coupled with proven effective performances are a green and cost-effective alternative to mitigate various pavement distresses. Various options either as coarse or fine aggregates and as fillers in powder, ash, or fibre form are to stimulate further research interest to incorporate a diversified range of solid waste into the asphalt binder and asphalt mixture. Prior to incorporating solid waste into the asphaltic mixture through the selected options, prerequisite tests in addressing engineering limitations due to the unknown properties of solid waste are reviewed. The concerns on environmental impact are given heavy metals leaching possibilities into water sources are addressed by Toxicity Characterization Leaching Procedure test, to leverage further the systematic reuse of solid waste in steering towards the cleaner production of the asphalt mixture. The microcosmic traits of solid waste namely surface morphology, mineralogical composition and chemical composition are summarized based on the usage of Scanning Electron Microscope, X-Ray Diffraction, and X-Ray Fluorescence, respectively. This systematic review is an enactment and stimulus for researchers to have a general overview before incorporating solid waste into asphalt mixture.