Capillary tension theory for predicting shrinkage of concrete restrained by reinforcement bar in early age

Abstract In this study, we proposed a method for predicting early shrinkage of concrete restrained by reinforcement bar based on capillary tension theory and microstructure pore of concrete. Concrete specimens with two different strength grades and four different reinforcement ratios were prepared. The pore structure, shrinkage, and physical properties of concrete were investigated at ages of 3, 7, and 28 days. Experimental results show that the reinforcement bar changed the pore structure of the concrete. The pore structure size of the concrete increased linearly with increase in the reinforcement ratio. Concrete shrinkage restrained by reinforcement bar decreased. It was because of the co-deformation between concrete and reinforcement bar and restrictions on capillary stress. The predicted values of shrinkage of concrete restrained by reinforcement bar were in good agreement with measured values.