Simulation of Time-dependent Tensile Behavior of Concrete under Various Loading and Drying Path

Stress analysis, considering spatial distribution of shrinkage and time-dependent deformation characteristic, should be carried out in order to predict accurately tensile stress and associated crack in concrete member under restraint drying shrinkage. In particular, a constitutive model for concrete that can adequately express tensile creep under drying is of importance. A new apparatus for sustaining tensile test of concrete was developed in this study to obtain reliable data of tensile creep of concrete, which can be a basis to develop an accurate computational model. The testing system, using cylindrical specimen, ensures comparison between experimental and analytical results under ideal conditions. Tensile stress and strain of the specimen can be precisely and stably controlled by inducing tensile load into the specimen as a reaction of compressive load in steel rod connected by screw. Consequently, time-dependent tensile behavior (i.e., stress, strain and cracking) of concrete can be tested under various loading and drying path programs. Test results obtained the proposed apparatus are demonstrated. Numerical simulation of tensile behavior of concrete is also conducted in this study. It was verified that reduction of tensile stiffness and cracking stress of concrete under drying can be simulated by strain softening near the surface due to restrained shrinkage.