Performance of Cracked Ultra-High-Performance Fiber-Reinforced Concrete Exposed to Dry-Wet Cycles of Chlorides

Longlong Niu,Shiping Zhang

doi:10.1155/2021/4625972

Abstract

This paper presents an experimental study on the performance of cracked ultra-high-performance fiber-reinforced concrete (UHPC) exposed to dry-wet cycles of 3.5% NaCl solution under the temperature of 60°C. The results show that the wider the crack, the higher the corrosion degree of steel fibers embedded in UHPC, and the deeper the chloride ion diffusion on both sides of the crack. With the increase of dry-wet cycles, the flexural strength of precracked UHPC first decreases and then increases, and the lowest flexural strength was observed in 60 dry-wet cycles. Although self-healing is hard to cease the corrosion of steel fibers, it can relieve the corrosion of steel fibers and improve the flexural strength exposed to 100 dry-wet cycles.

Highlights

Abbas et al [8] reported that the corrosion of steel fibers in ultra-high-performance fiber-reinforced concrete (UHPC) was only limited to the surface, and there was no degradation of mechanical properties after being exposed to chloride ion solutions for 6 months
Cracks in UHPC could be self-healed with the moisture and carbon dioxide (CO2) in the atmosphere. e effect of self-healing of UHPC on corrosion of steel fiber and mass transport needs to be investigated and analyzed, especially for partial self-healing. is research focused on the corrosion of steel fiber, mechanical strength, and self-healing of precracked UHPC with the crack width of 0.15 mm, 0.3 mm, and 0.5 mm exposed to dry-wet cycles of 3.5% NaCl solution for 0, 15, 30, 60, and 100 dry-wet cycles. e effect of self-healing UHPC on corrosion of steel fiber and mechanical strength was discussed from mass transport
It can be predicted that the performance would deteriorate for partial self-healing UHPC under long-term corrosive exposures

Summary

Introduction

Yoo et al [12] found that the steel fibers incorporated in the cracked UHPC matrix could be corroded, increasing their tensile performance due to increased surface roughness. The effect of steel fibers corrosion on the mechanical property of UHPC was evaluated, the self-healing phenomenon was not considered. Some researchers pay attention to the effect of self-healing on the mechanical properties or durability of UHPC without considering the corrosion of steel fiber. Is research focused on the corrosion of steel fiber, mechanical strength, and self-healing of precracked UHPC with the crack width of 0.15 mm, 0.3 mm, and 0.5 mm exposed to dry-wet cycles of 3.5% NaCl solution for 0, 15, 30, 60, and 100 dry-wet cycles. E effect of self-healing UHPC on corrosion of steel fiber and mechanical strength was discussed from mass transport

Methods

Results

Conclusion