Strain localization mechanism of interfacial failure in steel fiber/concrete specimens

The full strain field near the interface of steel fiber/concrete in a half-mold specimen was measured using a combined method of pullout test and digital image correlation. The strain localization mechanism of the interfacial failure is discussed. The strain distributions near the interface at a straight fiber under different loads show that the interfacial shear failure has a distinct characteristic of intervals in time and space directly related to the strain localization, which makes the interfacial failure initiate, develop and transfer successively. In particular, the local strain distributions around pores near the straight fiber interface demonstrate that the strain changes its sign at the irregular parts of the pore where the initial debonding took place and the deformation path is affected by the pore.