Fan Xiyan, Lu Weiwei, Lv Songtao, He Fangwei
National Engineering Laboratory of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China.
Materials (Basel). 2019 Jul 24;12(15):2358. doi: 10.3390/ma12152358.
To improve the low-temperature performance of the Buton rock asphalt (BRA)-modified asphalt, styrene-butadiene rubber (SBR) was added to it. The BRA-modified asphalt and SBR-BRA composite modified asphalt were prepared by high-speed shearing method. The penetration, softening point, ductility, and Brookfield viscosity of the two kinds of asphalt were measured. The dynamic shear rheometer (DSR) and the beam bending rheometer (BBR) were employed to research the performance of BRA-modified asphalt by adding SBR. The results showed that the pure asphalt in BRA was the main reason to reduce the low-temperature performance of neat asphalt when the content of BRA was 19%. However, the ash in BRA was the main factor to reduce the low-temperature performance when its content was more than 39.8%. When the BRA content was 59.8%, the SBR-BRA composite modified asphalt with SBR contents of 2%, 4%, 6%, and 8%, and it shows that the penetration and ductility of the BRA-modified asphalt are increased by the addition of SBR. The equivalent brittle point was reduced, the stiffness modulus was decreased, and the creep rate was increased. At the same time, the Brookfield viscosity was reduced and the rutting factor was increased. The stiffness modulus of the SBR-BRA composite modified asphalt mixture was increased. That is to say, when SBR was mixed into the BRA-modified asphalt, the low-temperature performance could be remarkably improved based on ensuring high-temperature performance. The low-temperature index of composite modified asphalt was analyzed. It was recommended to apply the equivalent brittle point to evaluate the low-temperature performance of SBR-BRA composite modified asphalt.
为改善布敦岩沥青（BRA）改性沥青的低温性能，向其中添加了丁苯橡胶（SBR）。采用高速剪切法制备了BRA改性沥青和SBR - BRA复合改性沥青。测定了两种沥青的针入度、软化点、延度和布氏粘度。采用动态剪切流变仪（DSR）和梁式弯曲流变仪（BBR）研究了添加SBR对BRA改性沥青性能的影响。结果表明，当BRA含量为19%时，BRA中的纯沥青是降低纯沥青低温性能的主要原因。然而，当BRA含量超过39.8%时，BRA中的灰分是降低低温性能的主要因素。当BRA含量为59.8%时，制备了SBR含量分别为2%、4%、6%和8%的SBR - BRA复合改性沥青，结果表明，添加SBR提高了BRA改性沥青的针入度和延度。当量脆点降低，劲度模量减小，蠕变速率增大。同时，布氏粘度降低，车辙因子增大。SBR - BRA复合改性沥青混合料的劲度模量增大。也就是说，将SBR混入BRA改性沥青中，在保证高温性能的基础上，可显著提高其低温性能。分析了复合改性沥青的低温指标。建议采用当量脆点来评价SBR - BRA复合改性沥青的低温性能。
