Styrene-butadiene-styrene (SBS) is widely used in asphalt modification and the investigations about SBS modified asphalt are focused on high temperature property, storage stability and the compatibility between SBS and asphalt. While the study on influencing factors on low temperature properties are not sufficient yet. In this paper, a systematical research was conducted to evaluate the influencing level of important factors such as SBS polymer type, SBS content, sulfur content and addition of rubber processing oil. Firstly, bending beam rheometer (BBR) test associated with Burger's model was used to evaluate the low temperature property and relaxation capacity. Furthermore, FTIR, GPC and DSC tests were conducted to investigate the chemical changes in SBS modified asphalt. At last, the low temperature performance of SBS modified asphalt mixture was investigated with thermal stress restrained specimen test (TSRST). In this paper, the optimum modification scheme of SBS modified asphalt binder and mixture was investigated and summarized. SBS polymer is swollen by saturates and aromatics which made the base binder lack of maltene fraction. While the further addition of rubber processing oil supplemented the maltenes which improved the low temperature property.@en

To meet the high temperature and anti-reveling properties required in open-graded friction course, high content polymer modified asphalt (HCPMA) is gradually widely used in China, but the rheological, chemical and aging characteristic is not clear yet. In this paper, HCPMA with different SBS content and different base asphalt are prepared, and Pressure Aging Vessel (PAV) aging was conducted to simulate the long-term aging condition. The chemical and rheological evaluation of HCPMA before and after aging were tracked with Fourier transform infrared, gel permeation chromatography test, dynamic shear oscillatory test, master curve and multiple stress creep and recovery test. The results show that firstly, the aging of HCPMA is combined with hardening of asphalt and degradation of Styrene–butadiene–styrene (SBS) polymer. Furthermore, the addition of high content of SBS polymer can reduce the formation of carbonyl, but the degradation rate of SBS polymer is not related to the content of SBS or the type of base asphalt. Besides, HCPMA with a higher SBS content will have better rheological properties, but in consideration of economy, 9% is optimum dosage. At last, HCPMA prepared with Esso asphalt as base binder exhibits better rheological properties than HCPMA prepared with SK asphalt. However, the rheology difference reduces with the increase of SBS content and after PAV aging.@en

Terminal Blend (TB) hybrid asphalt binders are composed of crumb rubber, SBS polymer and polyphosphoric acid (PPA). Understanding the relationship between the chemical composition and low temperature properties has a guiding significance for asphalt modification. In this study, BBR (Bending Beam Rheometer) test, GPC (Gel Permeation Chromatography) test, FTIR (Fourier Transform Infrared) test and DSC (Differential Scanning Calorimetry) test were used to evaluate the rheological and chemical properties of TB hybrid binder and TSRST (Thermal Stress Restrained Specimen test) was conducted to estimate the low temperature properties of mixture. The results indicated that crumb rubber and SBS improved low temperature properties, while PPA had an adverse effect. Furthermore, during the degradation of crumb rubber, aliphatic component was released, which played an important role in improving low temperature properties. Finally, TB hybrid asphalt mixture also had better low temperature properties than SBS modified asphalt mixtures according to TSRST results.@en