A comparative life cycle assessment of asphalt mixtures modified with a novel composite of diatomite powder and lignin fiber

Abstract

Some additives such as lignin fiber and diatomite powder were developed and used as modifiers in asphalt mixes to enhance the asphalt pavement performance by mitigating pavement distresses such as rutting, thermal cracking, and freeze–thaw cycles. Despite various advantages obtained from utilizing the additives in modified asphalt mixtures, there are many uncertainties regarding their environmental impacts. This study aims to analyze and evaluate the environmental impacts of four types of asphalt mixtures namely, Control Asphalt Mix (CAM), Diatomite Modified Asphalt Mix (DMAM), Lignin Fiber Modified Asphalt Mix (LFMAM), and Diatomite-Lignin Fiber Composite Modified Asphalt Mix (DLFMAM) through applying the life cycle assessment (LCA) methodology. Results demonstrate that DMAM and CAM offers distinct improvements in all impact categories as compared to other types of asphalt mixtures. As well as, the environmental burdens of DMAM is similar to CAM. Nevertheless, LFMAM showed higher negative impacts in all categories, followed by DLFMAM. Excluding the HTP (Human Toxicity) impact, both LFMAM and DLFMAM offer minimal negative effects in all other impact categories compared to the control asphalt mixture. Thus, it can be concluded that the usage of DMAM, LFMAM, and DLFMAM does not result in an excessive risk to the environment, and their applications as alternatives to the base asphalt mixture do not cause significant deteriorations in the environmental profile.