再生混凝土骨料咬合及剪力传递机理

Aggregate Interlock and Shear Transfer Mechanism in Recycled Aggregate Concrete

摘要:

通过预裂再生混凝土push off试件的裂缝处剪力传递性能试验，研究了再生混凝土裂缝处骨料咬合及剪力传递性能.结果表明：再生混凝土裂缝处剪力传递性能总体上与普通混凝土较为接近；约束刚度越大，试件的剪力传递强度越高；再生混凝土强度越高，试件的剪力传递强度有一定的提高；相同混凝土强度下，随着再生粗骨料取代率的提高，试件剪力传递强度略有降低.借鉴Walraven的理论，并考虑再生混凝土的细微观结构与再生粗骨料的几何特点，得到了再生混凝土中的骨料咬合模型.试验中各试件的剪力传递强度值与相关理论计算值吻合良好.

Abstract:

Based on the tests of pre crack push off specimens, the aggregate interlock and shear transfer performance of recycled aggregate concrete (RAC) were investigated. The experimental results reveal that the shear transfer performance across cracks in RAC is similar to that in natural aggregate concrete. When the constraint stiffness is larger, the shear transfer strength of RAC is also higher. With the increase of the RAC strength, the shear transfer strength of the specimen is improved but not obviously. Under the same strength of concrete, the shear transfer strength of specimens decreases slightly with the increase of recycled coarse aggregate replacement ratio, but it decreases marginally. On the basis of Walraven’s investigation and a consideration of the meso structure of RAC as well as the geometry shape of recycled coarse aggregate, an aggregate interlock model for RAC is developed. The shear transfer strength values of each test specimen and the values calculated by the theory agree well with each other.