Evaluating Bituminous Mix With Waste Rubber Pyrolysis Oil-Modified Bitumen And Char As Filler

Abstract: The automobile industry is the leading contributor to global solid waste generation, which mainly consists of rubber waste from tyres. Rubber waste is non-biodegradable, which is harmful to the environment. Using waste products to construct flexible pavement is a sustainable way of dealing with these concerns. This study addresses the issue by preparing the modified bituminous mix having bitumen modified with pyrolysis oil obtained during the process of pyrolysis of waste rubber tyre at 700 ℃ and incorporating the pyrochar, which is the end product of waste rubber pyrolysis, as the partial replacement of filler material. The Waste Rubber Pyrolysis Oil Modified Bitumen (WRPOMB) is primarily prepared by adding 1% of Waste Rubber Pyrolysis Oil (WRPO) in the neat bitumen VG30. The bituminous mixture was formed by incorporating the 1% WRPOMB and replacing the filler material in proportions of 10%, 20%, 30%, 40%, and 50% of filler with Rubber Pyrolysis Char (RPC). The marshal stability test was performed to evaluate the stability of the modified bituminous mix. The marshal samples were prepared on the Superpave Gyratory Compactor (SGC), and three samples were prepared for each combination. Modifying the WPRO with base bitumen enhances the stability and flow value of the mix, making it more stable and flexible to carry higher loads. Adding 1% WRPO in base bitumen was observed to increase the marshal stability value by 12.5% to that of VG-30 at a bitumen content of 4.5%. Further addition of the RPC as a partial replacement of filler in the bituminous mix leads to an increase in stability of the mix up to 40% RPC. However, there is a small decrease in the corresponding flow value, which results in a decrease in the flexibility of the mix. The 50% RPC modification does not hold well, as it reduces the binding ability of the binder. To incorporate more RPC than 40%, binder content needs to increase to prepare the firm specimens. Incorporating waste rubber pyrolysis products into the bituminous mix offers a sustainable solution for constructing flexible pavements.