Study of Bituminous Concrete Mix of Grade-Two for Stability and Flow Analysis using Additives of Waste Materials

Abstract

Typically, a bituminous mixture consists of coarse aggregate, fine aggregate, filler, and binder. A type of bituminous mixture called "Hot Mix Asphalt" (HMA) is made by mixing, placing, and compacting all of these components at high temperatures. Bituminous Concrete (BC) is a type of Dense Graded mix (DGM) used as a surface and wearing course in flexible pavements. It is essential for the wearing course to provide a smooth and dense riding surface while enduring traffic-induced wear and tear. The growth of transportation infrastructure plays a vital role in national development, and with flexible pavements widely used in India, efforts must be made to increase the longevity of bituminous pavements. Flexible pavements often face challenges such as cracking and rutting due to repeated traffic loads, which need to be addressed to enhance their performance.

This project focuses on evaluating the suitability of waste plastic bottles, discarded tyre rubber, and coconut fibers as reinforcing materials in Bituminous Concrete Grade 2 mixes. The Marshall method of mix design was utilized to determine the optimum bitumen content for the mixes, and their performance was analyzed accordingly. The optimum binder content was found to be 6% using 60/70 penetration grade bitumen. The study involved stability and flow analysis of Bituminous Concrete Grade 2 mixtures with different percentages of bitumen replacement by waste materials such as waste plastic bottles, discarded tyre rubber, and coconut fibers. Experimental results showed that replacing the optimum binder content with 10% waste plastic, 6% crumb tyre rubber, and 1% coconut fibers increased the stability of the mix by 10.67%, 10.37%, and 10.08%, respectively. Additionally, the flow criteria specified by the Ministry of Road Transport and Highways (MORT&H) for BC Grade 2 were satisfied by all the additives. Among the three additives used in the study, replacing the optimum binder content with 10% waste plastic yielded the highest Marshall stability value.