拉应力作用下早龄期混凝土相对湿度响应试验研究OA北大核心CSTPCD

In order to systematically investigate the response law of the internal relative humidity of concrete at an early age to different tensile stress levels,a test method of the internal relative humidity of the concrete under constant axial tension was developed in this paper,and the response law of the relative humidity under different tensile stresses was studied experimentally.According to the experimental results and theoretical analysis,a linear model of the relative humidity and tensile stress of early-age concrete under one-side drying conditions was presented.The results show that the tensile stress causes the instantaneous decrease in the internal relative humidity of the concrete.When the tensile stress increases from 0.8 MPa to 3.2 MPa,the relative humidity change at the depth of 50,75,and 100 mm of the concrete increases from 0.5%,0.4%,and 0.3%to 0.8%,0.7%,and 0.6%,respectively.At the same time,with the increase in tensile stress,the decrease in the relative humidity gradually increases.Under the same tensile stress,the response of relative humidity of the concrete,close to the exposed surface,to tensile stress which is is more obvious.The relative humidity gradually recovers during the tensile stress loading,and the time is about 2.5 h.A similar phenomenon also occurs during the compressive stress loading,and the time is about 20.0 h.Therefore,the relative humidity recovery time is shorter during the tensile stress loading.