Response law and diffusion coefficient of moisture in concrete with load stress

Abstract

Internal micro-environment in concrete is a direct environmental factor that influences the durability of reinforced concrete (RC) structures. In order to explore the response laws between internal micro-environment in concrete and external climatic environment under actual service state, the experiments on the responses of relative humidity (RH) in concrete have been performed under different load stresses in an artificially controlled climatic environment. The results show that the load stress has an appreciable effect on the RH response in concrete. Compressive stress reduces the rate of RH response in concrete, contrary to the accelerated effect by tensile stress. Tensile stress shows more significant effect on concretes with smaller water–cement ratio. Compressive stress has more significant effect on concretes with larger water–cement ratio. Finally, a model to predict the equivalent diffusion coefficients of moisture in concrete has been proposed considering the effects of compressive and tensile stresses.