Time-dependent corrosion process and non-uniform corrosion of reinforcement in RC flexural members in a tidal environment

Abstract

Abstract In this paper, the time-dependent corrosion of tensile reinforcements in RC beams with two water-to-cement (W/C) ratios under flexural load is studied, based on the accelerated chloride penetration tests within 400 d exposure time. The mass and volume corrosion rates of tensile reinforcements were obtained by the weighing method and three-dimensional (3D) laser scanning technique, respectively. Moreover, the 3D laser measurement data was used to determine the distribution of residual cross-sectional areas of corroded tensile reinforcements along reinforcement length and analyze the non-uniformity of corroded tensile reinforcements. Then, a prediction model of maximum area of corrosion of tensile reinforcements was determined. The feasibility of prediction model was certified by comparing the predicted values with measured values obtained by the 3D laser scanning technique. Results indicate that the mass corrosion rate of tensile reinforcements has an obvious time dependence. After about 320 d exposure time, the mass corrosion rates of tensile reinforcements increase rapidly with exposure time. Comparing with the mass corrosion rates, the volume corrosion rates can also be taken as another measurement indicator of uniform corrosion rates. Moreover, with the increasing of W/C ratio, exposure time and flexural load, the corrosion non-uniformity of tensile reinforcements along reinforcement length increases in different degrees, and flexural load has the greatest influence on the corrosion non-uniformity. In addition, under the different W/C ratios, exposure times and flexural loads, consistent change trends of predicted and measured maximum area of corrosion can be observed. Among them, the predicted maximum area of corrosion without flexural loads is more close to the measured value.