A Probabilistic Prediction Method of Concrete Surface Chloride Ion Concentration in Ocean Underwater Area

Abstract

A probability prediction method of the concrete surface chloride ion concentration in a marine underwater zone comprises the following steps that 1, a random sample point calculation model of the concrete surface chloride ion concentration in the marine underwater zone is established; 2, statistical characteristic values of probability model parameters of different types of concrete in the marine underwater zone are determined, and random sample points of the probability model parameters are produced; 3, the random sample points of the concrete surface chloride ion concentration in the marine underwater zone are produced, and a probability density function of the concrete surface chloride ion concentration in the marine underwater zone is determined. By adopting the method, the probability distribution characteristics of the concrete surface chloride ion concentration in the marine underwater zone can be reasonably described, the prediction precision of a traditional deterministic model can be calibrated, and accordingly the technical defects existing in the traditional deterministic model are overcome.

Description

technical field [0001] The invention relates to a method for predicting the concentration of chloride ions on the surface of concrete, in particular to a method for probabilistically predicting the concentration of chloride ions on the surface of concrete in the underwater area of ​​the ocean. Background technique [0002] In the chloride environment in the underwater area of ​​the ocean, due to the long-term immersion of the concrete structure in seawater, the corrosive chloride ions in the seawater can easily invade the interior of the concrete, resulting in corrosion of steel bars and rust swelling and cracking of concrete. Since the chloride ion concentration on the concrete surface is an important quantitative index reflecting the chloride corrosion environment in the underwater area of ​​the ocean, it is also an important boundary condition for the quantitative analysis and design of the durability of concrete structures, so the prediction of the chloride ion concentrat...

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Problems solved by technology

[0004] At present, the Japanese standard "Standard specifications for concrete structures-2007, "design"" and the Chinese standard "High Performance Concrete Quality Control Standards for Seaport Engineering" select the concentration of chloride ions on the surface of concrete in the marine underwater area as a constant for the convenience of engineering applications, and there is no Consider the effect of environmental conditions, material parameters and exposure time on the concentration of chloride ions on the concrete surface

[0005] In the technical report "Final technical report: probabilistic performance based durability design of concrete structures" issued by the European Union in 2000, considering the influence of water-binder ratio and the type of mineral admixtures, a calculation model for the concentration of chloride ions on the concrete surface in the underwater area of ​​the ocean was established, but The model does not take into account the effects of environmental conditions (such as seawater chloride ion concentration) and exposure time

[0006] The Portuguese technical regulation "Concrete-Part 1: specification, performance, production and conformity" released in 2007 considers the influence of seawater depth, temperature, seawater chloride ion concentration and water-binder ratio, and establishes the concentration of chloride ion concentration on the concrete surface in the underwater area of ​​the ocean. Calculation model, but this model does not consider the effect of exposure time and type of mineral admixture on the concentration of chloride ion on the concrete surface

[0007] In 2010, Zhao Yuxi, Wang Chuankun, and Jin Weiliang published a paper titled "Experimental Research on the Time-varying Law of Chloride Ion Concentration on Concrete Surface", based on the indoor immersion test data, a model of concrete surface chloride ion concentration considering time-varying characteristics was proposed, but Does not take into account the influence of material parameters and environmental conditions

[0008] The above models are all deterministic prediction models, which can only guarantee the overall optimality of the prediction results and experimental test values, but cannot describe the probability distribution characteristics of the chloride ion concentration on the concrete surface

[0009] In 2013, Zhong Xiaoping, Jin Weiliang, and Wang Yi published a paper titled "Standards for Values ​​of Variable Effects of Concrete Structures in Port Engineering", combined with literature research and engineering experience, determined the concentration of chloride ions on the concrete surface in the underwater area of ​​the ocean. mean and standard deviation, but cannot take into account the effects of water-binder ratio, type of mineral admixture, and exposure time on the probability distribution characteristics of the chloride ion concentration on the concrete surface in the underwater zone of the ocean

[0010] At present, there is no report on a probabilistic prediction method that can not only comprehensively consider the influence of water-binder ratio, concrete type, seawater chloride ion concentration and exposure time, but also reasonably describe the probability distribution characteristics of the concrete surface chloride ion concentration in the underwater area of ​​the ocean.

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