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采用带切口的试件进行半圆弯曲试验(SCB)可以更好地评价存在反射裂缝的沥青路面的抗裂性能。为了明确试件厚度、切口宽度、切口深度、支座间距等试验参数对带切口SCB试件力学响应的影响,采用ANSYS建立三维有限元模型对SCB试验进行数值模拟。计算结果表明:当试件厚度大于50 mm时,底部拉应力趋于定值,而试件厚度太薄会导致应力集中,因此试件厚度选择为50 mm;切口处底部拉应力随着切口宽度的增加逐渐减少,基本上成线性关系,为了便于观察试验现象并考虑到切缝切割工艺,切口宽度确定为1.5 mm;切口处底部拉应力随着切口深度的增加逐渐增大,为了选择适宜的切口深度,尚需对15、20、25 mm切口深度进行试验验证;支座间距选择为试件直径的0.8倍,此时切口底部拉应力值最大。
The semicircular bending test (SCB) using notched specimens can better evaluate the crack resistance of asphalt pavement with reflective cracks. In order to clarify the effect of test parameters such as specimen thickness, incision width, incision depth and bearing spacing on the mechanical response of notched SCB specimens, a three-dimensional finite element model was established by ANSYS to simulate the SCB test. The calculation results show that the tensile stress at the bottom of the specimen tends to be constant when the specimen thickness is more than 50 mm and the specimen thickness is too thin at the specimen thickness of 50 mm. The tensile stress at the bottom of the notch decreases with the width of the notch In order to facilitate the observation of experimental phenomena and taking into account the kerf cutting process, the width of the kerf was determined as 1.5 mm; the tensile stress at the bottom of the kerf increased gradually with the increase of the kerf depth. In order to select suitable Cutting depth, still need to 15,20,25 mm notch depth test verification; support pitch selection of 0.8 times the diameter of the specimen, then the maximum tensile stress at the bottom of the incision.