Factorial Experimental Analysis of Buton Natural Asphalt with Crumb Rubber in Asphalt Concrete Wearing Course (AC-WC)

Buton natural asphalt with crumb rubber (BNA-R) represents an innovative approach to enhancing the performance characteristics of asphalt mixtures. However, previous studies have primarily focused on incorporating BNA-R at a single, optimum dosage level. This study explores the impact of varied dosages of Buton natural asphalt with crumb rubber (BNA-R) on asphalt mixture performance using the factorial design analysis. The factorial design method is a statistical method to test the influence of several factors with different levels. With this method, all possible combinations of each level from the elements can be analyzed for their effects on the asphalt mixture without lethal or freeze other factors. Based on the analysis of two-level full-factorial designed experiments revealed on the Marshall test, it’s shown that: the bitumen content has a significant correlation with the flow, MQ, VIM and VFA, while BNA-R has a substantial relationship with stability, flow, VIM and VFA. Results show enhanced stability, increased Marshall Quotient (MQ), and improved workability with lowered production temperatures. While the correlation between asphalt levels and BNA-R content is not significant for mechanical properties, such as stability, flow, MQ, voids in mineral aggregate (VMA), and VFA, the presence of BNA-R alone exhibits influential relationships with these parameters and BNA-R alone influences these parameters. The results from the study suggest that the optimal combination identified is 5.6% asphalt with 20% BNA-R, 5.7% asphalt with 25% BNA-R, and 5.8% asphalt with 30% BNA-R.