In-situ monitoring method of steel bar corrosion risk in concrete

Abstract

The invention relates to a method of monitoring rusting risk of reinforcement in concrete in situ. The method includes the steps of 1, according to the principle of plane state of stress and stress concentration, applying prestress to rusting monitoring sensing units to enable them to be in a plane state of stress; 2, packaging three sides of each rusting monitoring sensing unit, and reserving one side as a rusting monitoring side; 3, distributing the rusting monitoring sensing units at equal intervals within a rectangular steel frame, before concreting, distributing the rectangular steel frame and the outer surface of concrete at a certain angle in an area to be subjected to reinforcement rusting monitoring, allowing the rusting monitoring sides to face a protective layer, and performing rusting monitoring through continuous strain measurement of different sectional heights of sheets. The method has the advantages that monitoring chloride threshold concentration fronts at different depths is achieved, initial rusting time of the reinforcement is predicted, results are updated according to monitoring data, the rusting monitoring sensing units as deep as the reinforcement allow the final initial rusting time, rusting rate and rusting degree of the reinforcement to be directly monitored.

Description

technical field [0001] The invention belongs to the technology of civil engineering structure health monitoring and reinforced concrete structure durability evaluation, and is applied to the corrosion monitoring and durability evaluation of reinforced concrete structures. Background technique [0002] The monitoring and prediction of the initial corrosion time of steel bars is a difficult problem in evaluating the durability of concrete. Chloride ion erosion in sea corrosion environment is the main cause of steel bar corrosion in concrete. At present, steel bar corrosion monitoring is mainly divided into physical and electrochemical methods. It is used to characterize the electrochemical state, physical state of steel or concrete, and various corrosion-inducing factors in the surrounding environment. The main methods used are: (1) Electrochemical monitoring method: Since steel bar corrosion in concrete is an electrochemical process, electrochemical measurement is an importan...

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Problems solved by technology

Its disadvantage is that the physical method of measuring the corrosion of steel bars is easily disturbed by other damage factors in concrete, such as micro cracks, etc., and it is difficult to establish the corresponding relationship between physical measurement indicators and steel bar corrosion, so the method of physical testing is not suitable for steel bars. Generally, the degree of corrosion can only provide qualitative conclusions, but it is difficult to provide quantitative analysis.

(3) Monitoring methods for factors affecting corrosion. Existing methods mainly focus on the monitoring of chloride ion concentration and pH value. The spalling of concrete will cause the sensor to fail; in addition, the impact parameters have the same problem as electrochemical methods such as resistivity testing in that the measured data can only evaluate the possibility of steel corrosion, but cannot quantitatively determine the specific corrosion of the steel

Existing methods are difficult to achieve quantitative analysis and prediction from time series at different depths, and the use of a single index or data from a single depth for analysis will lead to insufficient reliability of monitoring results; Corrosion is directly related, but the existing chloride ion sensor is difficult to realize long-term in-situ monitoring in the concrete environment due to the limitation of the preparation process and the materials used, and it is difficult to directly characterize the position of the critical concentration front through numerical values. Difficult to predict and quantify

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