基于黏弹性原理的低标号沥青低温应力分析

Thermal Stress Analysis of Low Penetration Asphalt Binder Based on Viscoelastic Principle

通过小梁低温弯曲试验(BBR)得到了沥青的低温黏弹性特征参数,采用广义Maxwell模型构建了低标号沥青黏弹性本构模型,并应用此模型计算了不同降温速率和温度下50#沥青的低温应力,并与70#,90#沥青和SBS改性沥青进行了对比.结果表明:在相同降温速率下,SBS改性沥青的温度应力最小,50#沥青的温度应力最大,表明低标号沥青容易发生低温开裂;降温速率对沥青的温度应力有显著影响,降温速率越大,沥青的应力越大;在实际工程中使用低标号沥青必须考虑环境温度的影响,应通过低温应力的计算来确定路面结构的可行性.

The low temperature viscoelastic characteristics of asphalt binder were measured using bending beam rheometer（BBR）. The general Maxwell model was adopted as the constitutive model to describe the viscoelastic behavior. Thermal stress of 50^# asphalt binder under different temperature decrease rates was calculated based on viscoelastic theory. Other three types of asphalt binders, 70^# , 90^# and SBS modified asphalt binder, were also tested and analyzed for comparison. It has been found that at the same tempera- ture decrease rate, SBS modified asphalt binder has the lowest thermal stress while 50^# asphalt binder has the greatest. As temperature decrease rate increases, the thermal stress increases significantly. The tem- perature effect must be considered in field application when using low penetration asphalt binder and the thermal stress should be taken into consideration for the pavement structure.