Effects of using lannea coromandelica gum and coal waste in hot mix asphalt pavement on vehicle overloading

Abstract The predominant type of pavement currently in use is flexible pavement constructed with a hot asphalt mixture. However, with economic development advancing in various regions, transportation challenges, such as vehicle overloading, especially in developing nations, have emerged. It is crucial to enhance and innovate the materials used in asphalt mixtures, which form the primary structure supporting pavement loads, to address these issues effectively. Incorporating green materials sourced from natural and waste sources becomes essential for promoting sustainable development. This study investigates the utilization of materials derived from the sap of the lannea coromandelica tree, known for its natural resin-like adhesives, as well as coal waste as a filler in asphalt mixtures. Laboratory experiments were conducted alongside vehicle load data analysis, focusing on excessive vehicle loads on roads. The findings indicate that incorporating these green materials enhances the modulus value of the asphalt mixture, particularly in the lannea coromandelica gum with fly ash (LCGFA) mixture, which amounted to 4161 Mpa, followed by the lannea coromandelica gum with bottom ash (LCGBA) mixture by 3729 Mpa, compared to the control mixture, hot mix asphalt concrete. Additionally, these results influence the Truck Factor value of vehicles. The higher the truck factor value, the impact on the pavement structure is due to the vehicle load transmitted through the vehicle axis, which is forwarded by the pavement to the subgrade. The adoption of LCGFA and LCGBA reduces the Truck Factor value from 5,386 to 4,980 under the LCGFA mix and 5,143 under the LCGBA mix, indicating decreased pavement damage caused by the wheel axles of overloaded vehicles. Consequently, utilizing these green materials is considered capable of providing enhanced durability and environmental benefits to pavement structures. In addition, this material can be used by field practitioners to reduce material costs and environmental impact.