Moisture Susceptibility of Lime-Modified Asphalt Mixture Containing EAF Slag: A Response Surface Methodology Approach

Moisture susceptibility has been recognized as a major pavement distress. This study examines the resistance to moisture damage of lime-modified asphalt mixtures containing EAF slag. For this study, seventeen (17) mixtures containing 0–4% of lime and 0–100% of slag was generated using Box Behnken Design (BBD) in design expert. The asphalt mixture samples were prepared and the moisture susceptibility was determined based on the immersion compression test (Index of retained strength). The experimental results obtained indicate that lime as additive helps reduce moisture damage of steel slag asphalt mixtures in several mechanical and chemical ways. The ANOVA indicate that the lime content is the most influencing and significant factor after showing the highest F-values of 10.93 and 6.73 for retained strength index at curing days of 1 and 21-day, respectively. The response surface shows that the Steel slag and lime have significant interactive effects on the RSI. Furthermore, the optimization result shows that 1.376% of lime, 100% steel-slag and 4.435% bitumen content are the ideal values to meet the design requirements.