Technical, Economic, and Environmental Investigation of the Effects of Rubber Powder Additive on Asphalt Mixtures

Abstract

The use of additive in asphalt mixture is one of the appropriate solutions to technically modify the properties of asphalt concrete. An additive is able to strengthen asphalt mix by modifying its technical features. On the one hand, it is possible that additives can increase financial costs thus making their use impractical. On the other hand, there are certain additives that can be used in a mix that do not cause additional costs. Moreover, they can improve the asphalt mix as well as its environmental effects. In this paper, by adding different percentages of rubber powder to bitumen and conducting Marshall tests, it was observed that the addition of this additive changes the results of the Marshall test. The results of the research showed that Marshall strength increases by increasing the percentage of rubber powder and then it decreases. In the following, the economic aspects of using additives were examined in the research as well. The results showed that adding 5% of rubber powder to the asphalt mixture is economically efficient and justifiable in practice. Moreover, analysis of the results proved that this additive reduces the effects of pollutants such as carbon monoxide (CO), methane gas (CH4), carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), sulfur dioxide (SO2), and dust particles less than 10 microns (PM10) in size in the air. These economic and environmental benefits justify employing rubber powder additives in asphalt mix. It was concluded that the results showed that asphalt mixture reinforced by rubber powder is more resistant and more rigid than the base mixture. Additionally, the mix can be used on a large scale (due to its significant economic efficiency and environmental safety) in a very warm climate and in areas with routine heavy traffic.