不同空隙率沥青混合料的形变及破坏

实验研究了不同空隙率沥青混合料的形变及破坏.结果表明:在所加载的压力范围内,空隙率为1.5%,2.5%,4.5%(体积分数,下同)时,沥青混合料的间接抗拉刚度模量与荷载成直线关系,沥青混合料呈弹性体;空隙率为8.0%,10.0%,12.0%时,沥青混合料的间接抗拉刚度模量与荷载呈非线性关系,并且在二者的关系曲线中出现一个拐点,沥青混合料会出现塑性变形.不同空隙率的沥青混合料具有不同的永久变形变化过程,其压实度对间接抗拉强度有显著影响.断面分析结果显示:空隙率为1.5%,2.5%,4.5%的沥青混合料破坏的同时将会有大骨料的断裂,而空隙率为8.0%,10.0%,12.0%的沥青混合料的破坏则表现为沥青砂(由小骨料、填充料及沥青等组成)的破坏.

Deformation and Damage of Bituminous Mixtures with Different Air Void

The deformation and damage of bituminous mixture with different air voids were investigated.The test results indicate that the relationship between the indirect tensile stiffness modulus(ITSM) and stress level is linear under the air void of 1.5%,2.5% and 4.5%(by volume),and the mixtures are in the stage of elastic deformation.The relationship between the ITSM and stress level is non-linear under air void of 8.0%,10.0% and 12.0%(by volume).Moreover,turning points are found on the curves of stress level versus ITSM and the mixtures aren't in the stage of elastic deformation.The mixtures with different air voids represent different deformation stages due to different interface structures resulted from different compaction condition.The indirect tensile strength tests show that the air voids affect the cohesion between aggregates and asphalt remarkably.The damage pictures show that the fracture of mixtures with 1.5%,2.5% and 4.5% air void occur with breakage of aggregates whereas mixtures with 8.0%,10.0% and(12.0%) air void is damaged with the parting of interface between aggregate and binder.