Plastic Waste Use in Road Construction: Viable Waste Management?

Abstract

Recently a lot of interest has been taken in waste plastic use, for the first time in a trail one Kilometer Road construction in Islamabad, Pakistan. Waste plastic in road construction has been used, earlier in a few developed and developing countries. Plastic waste is considered a fast emerging & alarming waste management issue worldwide, including Pakistan. Literature survey/review has indicated several research reports, with regard to assessment of plastic use viability in road construction, in terms of environment protection, public health (including workers), road quality as well its economic feasibility. According to Ayub et al (2017), the chemicals in waste plastic do not degrade easily in natural environment and more importantly the use of plastic in product delivery services could not be banned due to its comfortability, diverse use and less cost. Bjerkli (2005) and Bailey.R et al (2001) reported waste plastic use in road construction primarily, as an economic phenomenon, with observation during studies that community attitudes, government policies, cost of waste disposal and material scarcity would create market for the consumers. Global literature also identified groups of material from other waste sources (such as waste oil, tires, aggregates, asphalt and bituminous surfaces) that has been used in waste recycling process. Bindu and Beena (2010) carried out a study on “Waste Plastic as a Stabilizing Additive in Stone Mastic Asphalt,” and the performance tests indicated the benefits of stabilizing the Stone Mastic Asphalt (SMA) with an increase in plastic content by 10%, resulting in an effective stabilizing mixture for plastic road pavements. Menaria and Sankhla (2015) claimed that the significance of waste plastic in road construction increased road durability and controlled heating (around 160 Co) increased the strength of the pavements. Sheema et al (2017) studied the properties of plastic waste in bituminous mixes, in which the shredded waste plastic poly-styrene was coated over aggregate and further mixed with hot bitumen which helped further strengthening and increased the durability of pavements. Nikraz et al. (2021) reported that 8% waste PET-modified asphalt mixture could be a sustainable and cost effective/ addictive, in rutting resistance and stability of the roads so constructed. Marshall Quotient, flow and stability tests also demonstrated that 6-8% of waste plastic use with modified mixture helps to enhance and amend elasticity behavior and stiffness of asphalt binders. In view of the above and several environmental and social considerations by Conlon (2021), in Global South context, where plastic waste quantum is high as well as existing lack of waste management infrastructure, waste plastic use in road construction could make road construction economical as well as eco-friendly.