硅藻土-玄武岩纤维复合改性沥青的低温流变性能试验研究

Laboratory Study on Rheological Performance at Low Temperature of Diatomite and Basalt Fiber Compound Modified Asphalt Mastic

已有研究表明,硅藻土-玄武岩纤维复合改性沥青的高温性能明显好于基质沥青,而对其低温性能改善作用仍不明确。为了评价硅藻土-玄武岩纤维复合改性材料对沥青低温性能的作用,通过BBR试验对6组不同掺量的硅藻土-玄武岩纤维复合改性沥青低温流变特性进行研究。选用Burgers模型描述复合改性沥青的低温流变行为,获取相应粘弹性参数对其低温流变性能进行分析。结果表明,Burgers模型对硅藻土-玄武岩纤维复合改性沥青的流变行为拟合效果理想。硅藻土的加入削弱了沥青的低温性能,随着玄武岩纤维质量分数的增多,沥青的低温抗裂性能和应力松弛能力先降低后增加。相比于基质沥青,掺量为(7. 5%和4%)的硅藻土-玄武岩纤维复合改性沥青的低温性能得到提高,并且硅藻土-玄武岩纤维复合改性沥青的低温抗裂性优于硅藻土改性沥青。

Studies have shown that the high temperature performance of diatomite and basalt fiber compound modified asphalt mastic is better than that of the base asphalt,while the improvement of its low temperature performance is still unclear.To evaluate the effect of diatomite and basalt fiber compound modified material on the performance of asphalt mastic at low temperature,six groups of diatomite and basalt fiber compound modified asphalt mastic with different content were prepared to study the rheological property at low temperature by the BBR test.Burgers model was used to describe the low temperature rheological behaviors of compound modified asphalt mastic,and the viscoelastic index was obtained to evaluate its rheological properties at low temperature.The results showed that the Burgers model is appropriate for the creep behavior of diatomite and basalt fiber compound modified asphalt mastic.The low temperature performance of asphalt mastic was weakened by adding the diatomite alone.When the content of diatomite was constant,the low temperature properties and stress relaxation ability of asphalt mastic descended first and then increased with the increase of basalt fiber content.Compared with the base asphalt,the low temperature performance of the diatomite and basalt fiber compound modified asphalt mastic with a content of 7.5% diatomite and 4% basalt fiber was increased.And the low temperature cracking resistance of diatomite and basalt fiber compound modified asphalt mastic is better than that of diatomite modified asphalt mastic.