Sustainability and Performance Evaluation of Rubberized Asphalt Mixtures Using Different Production Methods

Description

Sustainability and Performance Evaluation of Rubberized Asphalt Mixtures Using Different Production Methods

Mohammad Zia Alavi*, Fateme Labbafi, Farnaz Saadat

School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.

Corresponding Author: zia.alavi@ut.ac.ir

ABSTRACT. This study evaluates the performance, cost, and environmental impacts of rubberized asphalt mixtures—produced through dry process, wet process with asphalt rubber binder, and wet process with terminal blend binder—in comparison with conventional hot mix asphalt (HMA). Using a life cycle assessment approach and SimaPro software, results demonstrate that rubberized mixtures, especially RHMA-tb, exhibit superior mechanical performance, notably in cracking, rutting, and moisture resistance. Mechanical scores were highest for RHMA-tb (100), followed by RHMA-wet (96.7), RHMA-dry (92.2), and HMA (73.3). Cost analysis revealed that RHMA-tb with 10% machine usage increase incurs only a 5% rise in production costs, while dry and wet methods without optimization increase costs by about 13%. Economic evaluation using Equivalent Uniform Annual Cost (EUAC) identified RHMA-wet as the most cost-effective over the pavement lifecycle. Environmental analysis showed slightly higher impacts for rubberized mixes due to higher binder content and mixing temperatures. Normalized scores were around 90–97 for rubberized mixtures and 88 for HMA. However, rubberized options produced lower GHG emissions per 1000 tons per year: 9.2 (RHMA-wet), 9.7 (RHMA-dry), and 10.2 (RHMA-tb) tons CO₂-eq, compared to 12.4 tons for HMA. Despite higher initial impacts and costs, rubberized asphalt mixtures offer long-term sustainability benefits, combining enhanced durability, reduced annual emissions, and lower lifecycle costs, making them strong candidates for sustainable pavement solutions.

KEYWORDS: rubberized asphalt mixtures, wet-process, dry-process, terminal blend binder, life cycle cost analysis, environmental impact.