Transfer Parameter Analysis of Chloride Ingress into Concrete Based on Long-Term Exposure Tests in China's Coastal Region

• Published in: Materials Vol. 15; no. 23; p. 8517
• Main Authors: Fan, Zhihong, Su, Dagen, Zhang, Zhijie, Zhong, Mingfeng, Zhang, Xinxing, Xiong, Jianbo, Li, Pengping
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 29.11.2022; MDPI
• Subjects: Accelerated tests; Analysis; Cement; Chloride; chloride diffusion coefficient; Chloride resistance; Coastal zone; concrete; Concrete structures; Diffusion coefficient; Durability; Environmental testing; exposure test; Laboratories; Life prediction; Marine environment; Offshore structures; Parameters; Penetration resistance; Performance evaluation; Permeability; Prediction models; RCM; Salinity; Service life; China; concrete; chloride diffusion coefficient; RCM; exposure test; durability
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15238517

Chloride penetration resistance is one of the most important performance measures for the evaluation of the durability of concrete under a chloride environment. Due to differences in theory and experimental conditions, the durability index (chloride diffusion coefficient) obtained from laboratory accelerated migration tests cannot reflect the real process of chloride ingress into concrete in the natural environment. The difference in test methods must be considered and the transfer parameter kt should be introduced into the service life prediction model when the test results of accelerated methods are used. According to the test data of coastal exposure in South China, the attenuation rule of the chloride diffusion coefficient of different cement-based materials changed with time and was analyzed in this paper. Based on the diffusion coefficient-time curve, the theoretical natural diffusion coefficients of 28 d and 56 d were deduced, which were compared with the chloride diffusion coefficients obtained from the non-steady-state rapid migration method (RCM) at the same age. Therefore, the transfer parameter kt that expounds the relationship between concrete resistance to chloride permeability under a non-stationary electrical accelerated state and natural diffusion in the marine environment can be calculated; thus, the RCM testing index can be used to evaluate the long-term performance of the concrete structure in the marine environment. The results show that the value of kt was related to environmental conditions, test methods, and binder systems.