Life Prediction of Reinforced Concrete in Saline Soil Based on Wiener Stochastic Process

In view of the short durability life of concrete structure in Western saline soil area, the reinforced concrete specimens were buried on site in the saline soil area of Golmud, and non-destructive degradation indexes such as ultrasonic velocity, quality and steel resistance of specimens were periodically collected every 150 d. Damage and deterioration evaluation was analyzed from both macro and micro aspects through the evaluation parameters of dynamic elastic modulus ξa, quality evaluation parameters ξb, evaluation parameters of steel bars without corrosion ξc and SEM images. Wiener random process was selected for modeling and life prediction. The results showed that under the combined actions of corrosive ions and climate, the ξa and ξb values of concrete fluctuated with a slight increase in the early stage and an accelerated decline in the middle and late stages. The value of ξa was more sensitive to the change of concrete performance, and the value of ξc of the steel bar decreased linearly. The Cl-, SO42-, CO32- and other corrosive anions in the saline soil enter the concrete through diffusion and capillary adsorption, and form Friedel's salt, silica fume gypsum, ettringite, gypsum, calcium carbonate and other corrosive expansion crystals with concrete hydration products. From a microscopic point of view, it was observed that the corrosion products in the concrete were distributed in sticks, rods, fibers, and needles. On the other hand, the corrosion products of steel bar were accumulated in granular and cluster shape, and there were corrosion pits on the surface of steel bar. The Wiener stochastic process model could well predict the life of reinforced concrete in saline soil environment, and the life curves of concrete and steel bar changed in three stages. The concrete life value obtained by the quality and dynamic elastic modulus degradation index was higher than the steel bar life obtained by the resistance degradation index, and the life value obtained by the concrete relative dynamic elastic modulus was lower than the life value obtained by the relative quality degradation index. Service life of C35, C40 and C45 reinforced concrete in Golmud saline soil environment was approximately 4500 d, 5000 d and 5800 d, respectively. Copyright ©2021 Advanced Engineering Sciences. All rights reserved.