Bond Slip Law and Micropore Structure of Freeze-thaw Concrete

Abstract

In order to study the influence of freeze-thaw cycles on the bond-slip relationship between concrete and steel bars, uniaxial compression and pull-out tests were carried out on concrete cubes experiencing 0, 25, 50 and 75 freeze-thaw cycles according to the existing stress models and the related concepts of ultimate bond force after freeze-thaw cycles. The bond stress and slip law between freeze-thaw concrete and steel bar are obtained. At the same time, the bond slip curve can be fitted by Bigaussian function. The results showed that with the increase of freeze-thaw times, the micro-pore structure on the surface and inside of concrete expands, the uniaxial compressive strength decreases, and the bond stress and slip between steel bar and concrete decrease.