Assessing the impact of waste LDPE and SASOBIT additives on the techno-economic performance of warm mix asphalt in Sri Lanka

Abstract

This research focuses on the use of waste LDPE (waste shopping bags) as an additive in asphalt mixtures for road construction in Sri Lanka. With the country’s limited infrastructure, the accumulation of waste plastic remains a significant environmental challenge. Consequently, this research aims to address environmental concerns while enhancing road performance through the incorporation of waste LDPE in Warm Mix Asphalt (WMA) technology. The related study investigates the mechanical properties, durability, and energy efficiency of waste LDPE-modified asphalt that includes Sasobit as an additive. Various laboratory experiments were carried out using different compositions of LDPE (2%, 4%, 6%, and 8% by weight of bitumen) along with Sasobit (3% and 5% by weight of bitumen). Results showed that 6% LDPE combined with 3% Sasobit generated the most enhanced performance for stability, flexibility, and environmental stress, like cracking and rutting, compared to the conventional asphalt mixture. Besides, the produced LDPE modified asphalt exhibited excellent workability with lower bitumen heating temperatures, which can save considerable energy consumption in producing LDPE modified asphalt. The cost analysis confirmed that mixing both LDPE and Sasobit into the asphalt mixtures were more beneficial from an economic perspective, due to the reduction in cost of material and energy consumption. Moreover, the incorporates LDPE waste also helps cope with the plastic pollution, and it gives sustainable solution for plastic problems with other waste management and infrastructure development. In conclusion, this research signifies that LDPE-modified asphalt mixtures can be employed as a sustainable alternative for Sri Lankan Road construction, serving the dual purpose of improving road quality and ameliorating plastic waste. Additional investigations are required to assess the long-term durability of these mixtures and to consider the incorporation of other types of plastic waste in the asphalt