Shrinkage of New Concrete Restrained by Old Concrete Based on Interface Roughness

Based on the analysis of the early shrinkage mechanism of concrete, shrinkage experiment of new concrete restrained by old concrete were conducted to analyze the impact of the different interface roughness on shrinkage stress of new concrete and bonding surface. It is shown that the inner tensile stress of new concrete decreases with increasing of interface roughness, and increase restrained thickness of the new concrete, but it is not significant effect of interface roughness on the shrinkage at bonding surface; the shrinkage strain of section reduces with reduction of the distance of section to bonding surface and reaches minimum on bonding surface, which reflecte significant nonuniformity and increases gradually with age.