DIBCH改性沥青及其混合料低温性能研究

Study on low temperature performance of DIBCH modified asphalt and asphalt mixture

为了改善沥青路面在低温下的服务水平,延长其使用寿命,采用环保型增塑剂环己烷二甲酸二异丁酯(DIBCH)对基质沥青进行改性,以高速剪切法制备不同DIBCH掺量(0、1.5%、2%、2.5%、3%)的改性沥青,以马歇尔法设计AC-13C型DIBCH改性沥青混合料,通过延度、针入度和弯曲梁流变等试验分析DIBCH对SK90沥青的改善效果,采用低温小梁弯曲试验评价SK90及改性沥青混合料的低温抗裂性能。结果表明:随DIBCH掺量的增加,SK90沥青的延度、当量脆点明显增大;DIBCH改性沥青蠕变劲度及蠕变速率较SK90沥青相比得到明显改善;通过力学和能量角度分析,DIBCH有助于改善SK90沥青混合料的低温抗裂性。综合DIBCH改性沥青及其混合料各低温性能指标分析得出其最佳掺量为3.0%。通过灰色关联分析可知,蠕变速率能够较好地评价DIBCH改性沥青的低温性能,采用抗弯拉强度(RB)能够较好地评价DIBCH改性沥青混合料的低温性能。

To improve the service level of asphalt pavement at low temperature and prolong its service life,the matrix asphalt was modified by environment-friendly plasticizer diisobutyl cyclohexane dicarboxylate(DIBCH),the modified asphalt with different DIBCH content(0,1.5%,2%,2.5%,3%)was prepared by high-speed shear method,and the AC-13C DIBCH modified asphalt mixture was designed by Marshall method.The improvement effect of DIBCH on SK90 asphalt was analyzed by ductility test,penetration test and bending beam rheological test.The low temperature crack resistances of SK90 and modified asphalt mixture were evaluated by low temperature trabecular bending test.The results shown that the ductility and equivalent brittleness of SK90 asphalt increased obviously with the increase of DIBCH content,and the creep stiffness and creep rate of DIBCH modified asphalt were obviously better than those of SK90 asphalt.Through mechanical and energy analysis,DIBCH was helpful to improve the low temperature crack resistance of SK90 asphalt mixture.Based on the analysis of the performance indexes of DIBCH modified asphalt and its mixture,it was concluded that the best content was 3.0%.The grey correlation analysis shown that the creep rate can better evaluate the low temperature performance of DIBCH modified asphalt,and the flexural tensile strength RB can better evaluate the low temperature performance of DIBCH modified asphalt mixture.