Experimental study on chloride penetration of the new-to-old concrete interface

Zhang, Juhui; Pan, Yitong; Li, Jing; Yun, Hui; Guan, Zhongguo

doi:10.1016/j.conbuildmat.2024.135585

Cited by 4 publications

(2 citation statements)

References 25 publications

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“…This phenomenon may be attributed to the decrease in bonding strength, in porosity, decrease in compactness, and appearance of microcracks at the bonding interface of the staged pouring concrete with the increase in casting interval, which serves as the main channels for chloride ion diffusion. Chloride ions penetrate the concrete through the microcracks at the bonding interface and react with the hydrated calcium aluminate in the concrete to form Friedel's salt [11,23,32], leading to the continuous consumption and outflow of needle-like hydrated products such as calcium hydroxide at the bonding interface, further increasing the porosity, and accelerating the deterioration of the interface. Chloride ions also diffuse from the bonding interface into the interior of the concrete and then spread to both sides, significantly accelerating the erosion of chloride ions [11].…”

Section: Effect Of Pouring Interval Time On Chloride Ion Concentratio...mentioning

confidence: 99%

“…Xia et al [22] investigated the chloride ion transport behavior of staged pouring concrete and found the presence of microcracks and a large amount of CaCO 3 in the pouring interface zone, with higher porosity than the concrete matrix on both sides, leading to deeper chloride ion diffusion into the concrete matrix. Zhang et al [23], through ultrasonic non-destructive testing and rapid chloride ion migration (RCM) tests, studied the interface bonding performance and chloride ion diffusion resistance of staged pouring concrete, indicating that with increasing pouring interval time, the difference in chloride ion diffusion between the new concrete area and the old concrete area becomes more pronounced. When the strengths of the new and old concrete are the same, chloride ion diffusion at the interface is closer to that of the new concrete.…”

Section: Introductionmentioning

confidence: 99%

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The Mechanical Properties and Chlorine Resistance of Concrete Based on the Effects of Pouring Interval Time

Chen,

Huang,

Wei

et al. 2024

Buildings

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In practical engineering construction, differences in time intervals during concrete pouring arise due to issues in concrete quality control and construction procedures, thereby affecting the mechanical and durability properties of concrete. This study conducted compressive strength tests, splitting tensile strength tests, and natural immersion tests to investigate the influence of time intervals in layered pouring on the mechanical strength and chloride ion concentration distribution of staged pouring concrete. Additionally, the study elucidated the mechanism by which pouring interval time affects the mechanical properties and resistance to chloride ion erosion of staged pouring concrete at the microstructure level. The results indicate that compared to ordinary concrete specimens, the splitting tensile strength of staged pouring concrete demonstrates a continuous decrease with increasing pouring interval time. The most significant splitting tensile strength decrease occurred at a 24 h interval. The compressive strength of staged pouring concrete initially decreases and then increases with increasing pouring interval time. At a pouring interval time of 12 h, the compressive strength of staged pouring concrete decreased the most. Results from the natural immersion tests demonstrate that chloride ion concentrations at the bonding interface and on both sides of staged pouring concrete increase continuously with the extension of pouring interval time. The chloride ion concentration at the bonding interface is consistently higher than that on both sides, and the difference between them decreases with increasing diffusion depth. The chloride ion concentration difference ΔC was proposed to evaluate the influence of bonding interface performance on chloride ion concentration, which decreases to varying degrees with increasing depth. The findings of this study can provide guidance for the research on the mechanical properties and durability of staged pouring concrete in practical engineering construction, as well as for engineering protective measures.

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Section: Effect Of Pouring Interval Time On Chloride Ion Concentratio...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Mechanical Properties and Chlorine Resistance of Concrete Based on the Effects of Pouring Interval Time

Chen,

Huang,

Wei

et al. 2024

Buildings

View full text Add to dashboard Cite

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Chloride transport through the interface in repaired marine concrete systems in a cracked state

Zhou,

Lu,

et al. 2024

Structural Concrete

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In repaired marine concrete structures, generally, an interface exists between old and new concrete, however, the influence of this interface on durability has yet not been well understood. In this study 18 reinforced concrete beams with new‐to‐old concrete interfaces (N–O interfaces) were designed to investigate chloride transport through a cracked interface. The effects of crack widths at the interface, concrete strain, and the chloride exposure time were considered, respectively. Results showed that the N–O interfaces having crack widths between 0 and 0.13 mm posed no significant impact on the chloride transport in the depth direction of the N–O interfaces, however when the crack width exceeded 0.13 mm, the chloride concentration gradually increased as the crack width increased. Chloride transport through the horizontal direction of the N–O interface was different between new and old concrete matrix when the crack width reached 0.18–0.20 mm. The surface layer with a range of 5–10 mm depth of concrete was sensitive to the variation of concrete strain, and the evolution of chloride concentration with concrete strain presented a logarithm relationship. Within the exposure period between 60 and 90 days, the increasing rate of chloride concentration was higher than that between 30 and 60 days. The study can provide some recommendations for repair of concrete elements exposed to a chloride‐laden exposure environment.

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Durability of new-to-old concrete interface under coupling action of freeze-thaw cycle and chloride salt erosion

Zhang,

Li,

Yun

et al. 2024

Structures

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Experimental study on chloride penetration of the new-to-old concrete interface

Cited by 4 publications

References 25 publications

The Mechanical Properties and Chlorine Resistance of Concrete Based on the Effects of Pouring Interval Time

The Mechanical Properties and Chlorine Resistance of Concrete Based on the Effects of Pouring Interval Time

Chloride transport through the interface in repaired marine concrete systems in a cracked state

Durability of new-to-old concrete interface under coupling action of freeze-thaw cycle and chloride salt erosion

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