Application of response surface methodology to evaluate stone matrix asphalt stripping potential

Stone matrix asphalt mixes are widely used in Western Europe due to its high strength properties in pavements, this type of mix is subjected to continuous wetting and drying cycles due to its porous structure leading to a higher potential for stripping. Lime has long been recognized and used in industry to reduce the stripping potential of SMA. Aggregate grading has also been identified to have an impact on the moisture damage potential. Response surface methodology was employed in this paper to evaluate the effect of lime content and grading on stripping potential of Stone Matrix Asphalt (SMA) using Tensile Strength Ratio (TSR) index. The statistical significances of linear, quadratic and interactive terms of the lime percent and grading were examined and second order polynomial regression equation was successfully fitted to the experimental results. The lime content of 1% and the finest aggregates resulted in a TSR optimum value of 91.8%±0.8%. It was further concluded that increasing the mastic asphalt would decrease the stripping potential of SMA and both of the two parameters evaluated, had approximately the same main effect on the TSR response.