Investigating the Effects of Loading Frequency and Temperature on Moisture Sensitivity of SBS-Modified Asphalt Mixtures

The main objective of this study was to investigate the effects of loading frequency and temperature on the moisture sensitivity of dense-graded polymer-modified asphalt mixtures using the creep curves derived from the dynamic creep tests. For this purpose, 96 Marshall specimens containing siliceous crushed stone aggregate with 85/100 penetration bitumen, modified with 4.5% of styrene-butadiene-styrene (SBS) polymer modifier, were fabricated and tested at four different loading frequencies, four temperatures, and two moisture conditions, dry and wet, with three replicate specimens for each experimental combination. The results showed that both the variables of loading frequency and temperature had significant effects on the permanent strains of both the dry and wet asphalt mixtures. As loading frequency increased under the dry condition, permanent strain decreased, and among the four temperatures, the highest permanent strain was measured at the lowest loading frequency. On the other hand, as loading frequency increased under the wet condition, permanent strain increased too and among the four temperatures, the highest permanent strain was measured at the highest loading frequency.