Fracture and Crack Mechanism of Bond-Slip Behaviors in SRC Composite Structures

摘要

The bond-slip behaviors between shaped steel and concrete are examined using five kinds of comparative tests. The data, reflecting bond failure of steel and concrete are measured in macroscopic and microscopic ways. The relationship between internal microphysical state change and macro-mechanical response of the interface is discovered. The classical damage concepts are extended to characterize the microphysical state evolution, and the result of evolution produces the bond-slip failure of the bond interface. The mechanism of interfacial micro-crack process and bond-slip failure are investigated in fracture and damage mechanics. A failure model of bond interface of steel and concrete is built up. A calculating method of fracture toughness of bond interface is provided, and the main parameters significantly affecting the fracture toughness are discussed quantitatively. The physical characteristics of the bond interface are analyzed. The influence of interfacial micro-crack process on bond-slip fracture toughness is researched. A calculating model of the banded micro-crack fracture process zone on bond interface is put forward, and the dimensions of fracture process zone are calculated from the banded fracture process zone model. The influence of fracture process zone on bond-slip fracture toughness is presented and modified using the critical fracture toughness.