Experimental and numerical study of an electromagnetic sensor for non-destructive evaluation of steel corrosion in concrete

Iron and steel industry emits a large amount of CO2 and SO2 in the process of steelmaking, and these acid gases lead to the serious corrosion damage of concrete structures. In this paper, the environmental characteristics and corrosion degree of concrete in a 41-year-old steelworks were investigated, and the neutralization life prediction of the concrete structure was carried out. The results showed that the temperature, relative humidity, CO2 concentration, and SO2 concentration in the steelworks were 1.32, 0.62, 1.28, and 13.93 times higher than those of the general atmospheric environment, respectively. These environmental characteristics in various sections were significantly different. The appearance change of concrete in the ingot casting bay was more serious than that of concrete in the billet bay. Both the compressive strength of concrete in the ingot casting bay and billet bay decreased, and the strength in the billet bay was relatively low. The neutralization depth of concrete in the ingot casting bay was 2.35 times larger than that of concrete in the billet bay. The prediction model of concrete neutralization depth was established, and the remaining neutralization service life in the ingot casting bay and billet bay were 194.68 a and 202.07 a, respectively.

Section: Life Prediction Of Concrete Structurementioning

confidence: 99%

Corrosion Damage and Life Prediction of Concrete Structure in a 41-Year-Old Steelworks

Niu

Liu

et al. 2022

“…The distribution function of the current density in the circumferential direction of reinforcement is defined as i(θ), and the distribution function of the rust thickness is defined as T r (θ). The geometric relationship between the current density distribution and the current is expressed by Equation (2). The geometric relationship between the thickness distribution of the rust layer and the volume of the rust product is given by Equation (3).…”

Section: Basic Principles Of Modelingmentioning

confidence: 99%

“…In order to maintain the long-term performance of a reinforced concrete structure, the detection and monitoring of the defects and degradation have attracted increasing attention. In terms of the durability of a reinforced concrete structure, steel corrosion is the main reason for the structural deterioration [1][2][3]. The corrosion of steel bars in concrete in the natural environment shows non-uniform corrosion, and the cracking pattern of concrete under non-uniform corrosion is very different from that of the uniform corrosion.…”

Section: Introductionmentioning

confidence: 99%

Rust Distribution of Non-Uniform Steel Corrosion Induced by Impressed Current Method

Gao

Yang

et al. 2022

Self Cite

The non-uniform corrosion of steel bars is the main factor affecting the durability of concrete. The cracking pattern of concrete due to corrosion is closely related to the distribution of the corrosion products. Research on the thickness distribution of the rust layer and the cracking pattern of concrete under different influencing factors is of great significance in the prediction of the service life of existing reinforced concrete structures and the avoidance of the premature cracking of the reinforced concrete structures to be built. This paper studies the thickness distribution of the rust layer on the surface of single and multiple corroded reinforcements under non-uniform corrosion. The electrochemical analysis of the electrified corrosion process was carried out by using the finite element analysis software, and the distribution of the current density was obtained. The effects of geometric parameters, steel bar position, and steel bar spacing and shape on the corrosion expansion cracking pattern were studied. The results indicated that as the position of the steel bar differed, the crack pattern of the concrete changed, depending on the number of corrosion peaks (i.e., the maximum thickness of the rust layer). In terms of the corner-located steel, the number of corrosion peaks varied in the cases of different geometrical parameters (i.e., the diameter of the steel bar and the distance between the steel bars and the stainless steel wire). Nevertheless, the critical corrosion degrees of the side-located and corner-located steel bars, with respect to the cracking of the outer concrete surface, were basically the same. Additionally, the ribbed steel bar presented a lower critical corrosion degree than that of the plain steel bar, while little influence was exhibited with the varying angles of the rib.

“…In the last few years, nondestructive testing measurements (NDT), such as dynamic or vibration tests, acoustic emission techniques, infrared image methods, and ultrasonic methods have been applied to assess the damage and infernal defects of civil engineering structures [13][14][15][16][17][18][19][20]. The optimization of concrete detection technology effectively improves the accuracy of detection and reduces the quality of concrete problems aroused by the building safety hazards, promoting the improvement of the quality of construction projects.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive Monitoring Hydration of Belite Calcium Sulfoaluminate Cement by EIS Measurement

Chi

Wang

et al. 2022

In this study, the impact of water-to-cement (w/c) ratios of belite calcium sulfoaluminate cement (BCSA) on the hydration kinetics and the electrochemical impedance spectroscopy (EIS) parameters is studied. According to the analysis of classic hydration measurements, such as calorimetry tests, chemical shrinkage content, and chemically bound water content, it can be concluded that a higher w/c ratio clearly accelerates the hydration of BCSA cement paste. The electrical resistivity of BCSA0.35 cement paste is more than 4.5 times that of BCSA0.45 and BCSA0.5, due to the gradually densified micropore structure blocking the electrical signal transmission rather than the free charged-ion content. The porosity of BCSA0.5 is 27.5% higher than that of BCSA0.35 and 7.8% higher than that of BCSA0.45, which proves the resistivity is clearly related to the variation in microstructure, especially for the porosity and pore size distribution. The novelty of this study is the linear regression with logarithm terms of electrical resistivity and classic hydration parameters such as chemical shrinkage, cumulative hydration heat, and chemically bound water is established to extend the classical expression of cement hydration degree. It indicates that the electrochemical impedance spectroscopy can be taken as a nondestructive testing measurement to real-time monitor the cement hydration process of cement-based materials.