Review of the utilization of plastic waste in asphalt pavements in hot climate conditions – KSA as a case study

Abstract

In recent years, many global efforts have been made to advocate for the incorporation of recyclable waste materials into construction projects that utilize versatile asphalt. Hence, this review presents the use of modified asphalt with recyclable plastic materials in road construction as it relates to stability under extreme high temperatures. As per previous analysis, the addition of plastic does increase permanent resistance along with the increased work capacity of the asphalt. Although the effect of temperature on the asphalt shows no clear-cut results, the work capacity preferably increases at low temperatures. Current results have shown that the addition of polyethylene terephthalate (PET) does not provide strength to the asphalt because of its high melting nature; however, the addition of polypropylene (PP) provides substantial strength to asphalt when used in the construction of roads. Moreover, the addition of polyethylene (PE) and polyvinyl chloride (PVC) does not provide much more strength when implemented on a large scale. This report presents bonding interactions between asphalt and plastic waste that demonstrate that chemical molecular modeling can be used to predict recyclable modified asphalt stability. Hence, FTIR data supports that adhesive interactions exist between the asphalt and plastic polymer materials. Modified asphalt mixtures demonstrated high levels of improvement with the addition of ethylene–vinyl acetate (EVA) and styrene–butadienestyrene (SBS), as these structures provide strength characterized by C–H and C-O bond stretching generated with Fourier Transform Infrared analysis (FTIR). Furthermore, identifying the microstructural changes of asphalt modified with plastics and following the physical dispersions are made easier with the use of SEM imaging analysis.