用粘弹性理论预测沥青混合料的劈裂疲劳寿命

Prediction of Indirect Tensile Fatigue Life of Asphalt Mixture by Means of Viscoelastic Theory

基于粘弹性理论，用拟应变来代替实际应变，建定了劈裂疲劳的破坏标准，推导了沥青混合料的劈裂疲劳寿命预测模型．通过劈裂蠕变试验确定了蠕变柔量、斜率、松驰模量以及拟应变等模型参数，预测了AC13沥青混合料在0．1和0．15应力比下的劈裂疲劳寿命．最后经劈裂疲劳试验验证，修正了预测模型．结果表明：预测模型可以较为准确地预估劈裂疲劳寿命，其离散性小于传统的劈裂疲劳试验，并可以大幅度减少试验量，节约试验时间．文中还给出了一个推荐的修正系数值，即0．713～0．757．

On the basis of the viscoelastic theory and by substituting the pseudo strain for the actual strain, a criterion of indirect tensile fatigue of asphalt mixture is established and a prediction model of the fatigue life is deduced. Then, the model is used to determine the parameters including the creep compliance, the slope value, the relaxation modulus and the pseudo strain, and to predict the fatigue life of AC13 asphalt mixtures with the stress ratios of 0. 1 and 0. 15. Moreover, the prediction model is modified via indirect tensile fatigue tests. The results indicate that, as compared with the traditional testing methodS, the proposed model can predict the indirect tensile fatigue life of asphalt mixture more accurately with small discrete value, simple testing procedure and short testing time. A recommended correction coefficient of the proposed model is finally presented as 0. 713 - 0. 757.