Study of chloride transport pattern in the interface zone of UHPC wet joints under different influencing factors

• Published in: Journal of Building Engineering Vol. 95; p. 110236
• Main Authors: Xu, Jun, Wang, Tao, Su, Chuanye, She, Wei, Fu, Chuanqing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.10.2024
• Subjects: Chloride diffusion coefficient; Chloride ion transport; NC-UHPC; UHPC wet joints; Chloride diffusion coefficient; UHPC wet joints; NC-UHPC; Chloride ion transport
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2024.110236

Numerous interfacial joints exist in precast assembled concrete structures. The application of ultra-high performance concrete (UHPC) to the wet joint areas of these structures can effectively improve the interfacial strength and erosion resistance of the joints compared to the use of normal concrete. However, the transmission rules and mechanisms of chloride ions in the interface zone of UHPC wet joints under different influencing factors (matrix strength, UHPC age, interface roughness, and interface moisture content) are still unclear. In this study, firstly, the chloride ion concentration in the interfacial zone of UHPC wet joints influenced by factors such as matrix strength, UHPC age, interface roughness and interfacial moisture content was determined using the drill hole powder extraction method combined with the rapid chloride ion content determination technique, and its distribution pattern and causes were analysed; Secondly, based on Fick's second law, combined with the experimental data reverse fitting, the chloride ion diffusion coefficients in the NC-UHPC interface zone under different factors were obtained, and a relationship model was established between the factors and the chloride ion diffusion coefficients of the interface zone; The research results indicate that the chloride ion concentration in the NC-UHPC interface zone gradually decreases with the increase of matrix strength, decreases with the increase of UHPC curing age, decreases with the increase of interface roughness, and initially increases and then decreases with the increase of interface moisture content. This research is of great significance for improving the durability of UHPC wet joint structures. •Chloride transport in the NC-UHPC interface region was studied.•The influence of matrix strength, UHPC age, interfacial roughness and interfacial moisture content were investigated.•Modelled the relationship between factors and chloride diffusion coefficients in the NC-UHPC interface region.