Stripping Potential of HMA and SMA: A Study Using Statistical Approach

This study was carried out to compare the moisture resistance of two types of mixtures [i.e., hot mix asphalt (HMA) and stone matrix asphalt (SMA)]. To achieve this purpose, three dense and three gap-graded aggregates were selected and tested according to a modified Lottman test procedure. The results were analyzed using a statistical methodology called response surface methodology (RSM). A mathematical model correlating stripping potential of mix with bitumen content and grading was developed based on statistical concepts that can be utilized for prediction purposes. The statistical analysis showed that except for the quadratic term of bitumen content in the case of indirect tensile strength (ITS) in saturated gap-graded mixtures, the linear, quadratic, and interactive terms of these factors were statistically significant in ITS of dry and saturated samples and the tensile strength ratio (TSR). Second-order polynomial models were also successfully fitted to the experimental data. The results indicated that SMA mixtures exhibit better moisture resistance than HMA mixtures.