ANALYSIS OF RESTRAINED SHRINKAGE OF INTERMITTENT CASTING CONCRETE SLAB IN THE EARLY AGE

Aiming at the high performance concrete in bridge engineering，bonding restrained shrinkage experiment of old and new concrete slabs with the different interface roughness and curing duration were conducted to investigate the early time-varying characteristics of the temperature and humidity of concrete and analyze the impact of curing duration on shrinkage stress of new concrete and bonding surface． The experimental results show that the thickness of new concrete impacted by the restraint of old concrete increases and the inner tensile stress of new concrete decreases with increasing of the roughness of bonding surface，however it is not so prominent for the effect of 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 at bonding surface，which reflects prominent inhomogeneity and increases gradually with concrete age; extending the curing duration can reduce shrinkage deformation and tensile stress induced by internal inhomogeneous shrinkage of concrete，thus reducing the risk of early crack of concrete slab．