Low-temperature cracking is one of the major distresses that asphalt pavements experience along with fatigue cracking and rutting. The low-temperature cracking arises during cold months when the temperature drops below the freezing point. As the temperature drops, thermal stress develops in the asphalt concrete (AC) layers due to the shrinkage of the materials. When the thermal stress exceeds the tensile strength of the AC, the low-temperature cracking occurs in the pavement. Since binder is the main bonding agent of the AC, at a lower temperature it needs to be flexible enough to resist the low-temperature cracking. Recently, the binder is being modified with styrene-butadiene-styrene (SBS) polymer to enhance the rutting and the fatigue performance. Though it is proven that the SBS polymer improves the rutting and the fatigue performance, the effect of SBS polymer on low-temperature performance is still unknown. To this end, this study investigates the low-temperature performance of polymer modified binders (PMBs) with different concentrations of SBS polymer. To retain consistency with the source, the SBS polymer is blended with a base (neat) binder (PG 64-22) using a high shear mixer at three different percentages: 1%, 3%, and 5%. After that, the lab produced binders are used to prepare the modified mixtures by maintaining same aggregate gradation and asphalt content. Finally, the low-temperature performances of the modified mixture samples are evaluated through thermal stress restrained specimen test (TSRST). It is found that both 3% SBS and 5% SBS PMBs show better low-temperature performance than the base binder.
展开▼
