Effect of Aggregate-Cement Paste Interface on Damage and Fracture of Concrete

The interfacial bond strength between aggregate and cement paste was changed by using different interface-treating technology for researching the effect of aggregate-cement paste interface on the stress-strain curve,fracture energy and crack propagation model of concrete.The study shows that enhancing the aggregate-cement paste interface can increase the compressive strength but decrease the toughness of concrete.Weakening the rough aggregate-cement paste interface can increase the strength with decreasing the tougthness of concrete at the same time.However,weakening the fine aggregate-cement paste interface can increase the fracture energy of concrete,the reason of which is that the initial imperfection in concrete induces the macro discrete crack into smeared crack that dispersed in the mortar,which can increase the effective crack length and the fracture process zone,so the deformation performance of concrete was improved obviously.