沥青混合料半圆弯曲试验影响因素研究

Research on Influencing Factors of Semicircular Bend Test of Asphalt Mixture

为研究几何参数对半圆弯曲试验的影响规律,确定合理的实验室半圆弯曲试验尺寸,依托某二级公路沥青混合料级配及组成设计,利用有限元软件建立半圆弯曲试验有限元模型,在此基础上采用控制变量法分析几何参数对半圆弯曲试验结果的影响。结果表明:试件半径在50~60mm时,对裂纹尖端应力强度因子影响很大,试件半径大于60mm后影响程度减小,确定的实验室半圆弯曲试件半径R=80mm,裂纹深度L、试件厚度H、支座间距与直径比值D等几何参数对应力强度因子的影响规律与半径R类似,最终确定的半圆弯曲试验几何参数为L=15mm、H=25mm、D=0.8。

In order to study the influence of geometric parameters on the semicircle bending test and determine the reasonable size of laboratory semicircle bending test,based on the gradation and composition design of asphalt mixture of a secondary highway,the finite element model of semicircle bending test is established by using the finite element software,and on this basis,the control variable method is used to analyze the influence of geometric parameters on the results of semicircle bending test.The results show that when the radius of the specimen is 50~60mm,it has a great influence on the stress intensity factor at the crack tip.When the radius is larger than 60mm,the influence degree decreases.The determined geometric parameters such as the radius of the laboratory semicircle bending specimen r=80mm,the influence law of the crack depth L,the thickness H of the specimen,the ratio D of the distance between the supports and the diameter on the stress intensity factor is similar to the radius R,and the final determined crack depth L=15mm,the thickness of the specimen H=25mm,the ratio of support spacing to diameter D=0.8.