论文部分内容阅读
冬季由于低温路面经常会被冰雪覆盖,融雪盐是对路面进行融雪化冰的主要方式之一。为了研究盐冻循环前后的基质沥青、SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)改性沥青和胶粉改性沥青的细观结构和低温流变性能变化,利用SEM和弯曲梁流变仪(BBR)对其测试。结果表明:改性剂以特定的结构形态存在于沥青中,二者具有良好的相容性,这种形态可以更好地吸附沥青,提高沥青的低温弹性或韧性,进而改善了沥青的低温性能。盐冻循环破坏了沥青的结构,影响了沥青的低温抗裂性能。经历盐冻循环后沥青的蠕变劲度模量增大、蠕变速率减小,低温抗裂和应力松弛能力降低,但改性沥青低温性能总体上优于基质沥青。因此建议北方等寒冷地区尽量选用改性沥青作为路面材料。
In winter, low-temperature pavements are often covered by ice and snow. Melting snow and salt is one of the main ways to melt snow on pavement. In order to study the mesostructures and the low-temperature rheological properties of SBS (styrene-butadiene-styrene block copolymer) modified asphalt and rubber modified asphalt before and after the salt-frost cycle, SEM and bending Beam Rheometer (BBR) to test it. The results show that modifier exists in bitumen with specific structure and has good compatibility. This modality can better adsorb bitumen, improve bitumen’s low-temperature elasticity or toughness, and improve bitumen’s low-temperature performance . Salt freeze cycle destroys the structure of asphalt, affecting the asphalt cracking resistance at low temperature. The creep billet modulus increases, the creep rate decreases, and the ability of anti-cracking and stress relaxation at low temperature decreases after going through salt frost cycle. However, the low temperature performance of modified bitumen is generally better than that of bitumen. Therefore, it is suggested that modified asphalt should be used as pavement materials in the cold areas such as the North.