Enhancing Rutting Resistance in Bituminous Concrete: A Response Surface Methodology Approach for Optimizing Bitumen and Hydrochar-Based Geopolymer Content

Abstract

In recent times, there has been a wave of concern about enhancing the durability and performance of bituminous pavements, particularly rutting resistance considering the rising traffic volumes and environmental concerns. Thus, modifying bitumen with biowaste materials such as hydrochar-based geopolymer composites is one new technique for resolving these challenges. Thus, this study investigates how the bitumen and hydrochar-based geopolymer composites (HBGC) affect the rutting resistance (RR) of bituminous pavements, utilizing an optimization known as the Response Surface Methodology (RSM). Three main design factors were investigated: bitumen content, hydrochar content, and geopolymer content. The asphalt binder content varied from 4% to 6%, whereas the biochar and geopolymer content ranged from 0% to 4%. The RSM technique was used to analyze the interplay between various design elements and develop a prediction model for optimizing the RR. The ANOVA analysis demonstrated strong statistical performance, indicating a high correlation between actual and predicted outcomes. Notably, the synergistic effect of increasing bitumen content and the use of a hydrochar-based geopolymer composite modifier resulted in improved RR in bituminous concrete. Furthermore, the study indicated optimal input content of 5.75% for bitumen, 3.4% for hydrochar, and 3.24% for the geopolymer modifier to improve RR. Also, the model has a 5% percentage error, showing a significant correlation between predicted and actual data. This study demonstrates the effectiveness of using RSM to optimize and predict HBGC bituminous concrete RR, by providing durability and sustainability through HBGC utilization in bituminous concrete.