浇筑式沥青混凝土应力应变关系试验研究

Experimental Study on Stress-Strain Relationship of Pouring Asphalt Concrete

对以天然砂砾石作为骨料的浇筑式沥青混凝土在不同沥青用量和不同温度条件下进行三轴试验。结果表明:浇筑式沥青混凝土的应力应变曲线呈现出应力硬化形态,且随着沥青用量的增加、温度的升高,应力硬化现象更加明显,双曲线段范围增大;邓肯-张模型及修正邓肯-张模型的理论曲线与试验曲线均吻合较好,主要模型参数随沥青用量增加或温度升高均呈下降趋势。通过对比两种本构模型破坏偏应力随围压的变化情况发现,在较高围压情况下,随着围压的升高,修正邓肯-张模型的破坏偏应力趋于平缓,增幅小,而邓肯-张模型的破坏偏应力几乎呈线性增加,其值明显大于修正邓肯-张模型的破坏偏应力,因此修正模型更加符合浇筑式沥青混凝土的强度特性。

The triaxial tests had been done on pouring asphalt concrete that aggregate was made up of natural sandy gravel under different asphalt content and different temperature conditions.The results show that the stress-strain curves of pouring asphalt concrete showing the stress hardening form,and with the increasing of asphalt content and temperature,the phenomenon of stress hardening is more obvious,the hyperbolic segment range increased;the theoretical curves of Duncan-Chang model and modified Duncan-Chang model are consistent with the test curve,the key model parameters show a decreasing trend with the increase in the amount of asphalt or temperature rise.Through the comparison of the destruction deviator stress between two constitutive models finds out that under higher confining pressure,with the increase of confining pressure,the destruction deviator stress of the modified Duncan-Chang model increase almost flat,growth rate reduce,the destruction deviator stress of the Duncan-Chang model increase almost linearly,its value is significantly greater than the destruction deviator stress of the modified Duncan-Chang model.AS a result,the modified Duncan-Chang model tally with the intensity character of pouring asphalt concrete.