超高性能混凝土抗氯离子侵蚀综述

A Review of Chloride Corrosion Resistance of Ultra-High-Performance Concret

延长钢筋混凝土结构服役寿命可有效降低其全寿命周期的经济、环境、资源、能源成本。然而, 很多钢筋混凝土结构在环境作用下常由于氯离子侵蚀导致钢筋锈蚀, 从而导致性能劣化, 进而失去使用功能, 甚至发生安全事故。作为钢筋与外界环境之间的屏障, 保护层混凝土可有效阻碍氯离子接触钢筋表面, 保护钢筋不受氯离子侵害, 从而提高结构的耐久性。超高性能混凝土由于水胶比低并剔除了粗骨料, 具有致密的微观结构, 可极大程度地阻碍氯离子在其内部的传输, 从而有望大幅提升钢筋混凝土基础设施的服役寿命。基于此, 本文首先总结了氯离子在水泥基材料内部传输的基本机制, 包括水泥基内部氯离子的运动方式与物理化学结合机制, 并分析了超高性能混凝土的氯离子渗透与氯离子结合能力的研究现状与改善方法。

Extending the service life of reinforced concrete structures can effectively reduce the economic, environmental, resource and energy costs throughout their life cycle. However, a large number of reinforced concrete structures often suffer from corrosion of reinforcing bars due to chloride ion erosion in various environments, which leads to deterioration of performance, the loss of functionality and even safety accidents. As a barrier between reinforcing steel and the external environment, protective layer concrete can effectively prevent chloride ions from contacting the surface of reinforcing steel, thus delaying the corrosion of reinforcing steel and improving the durability of reinforced concrete structures. Ultra-high-performance concrete has a dense microstructure due to its low water-to-cement ratio and elimination of coarse aggregates, which can greatly impede the transport of chloride ions within it, and thus it is expected to significantly improve the service life of reinforced concrete infrastructure. Based on this, this paper firstly summarizes the basic mechanism of chloride ion transport inside cementitious materials, including the movement mode and physicochemical binding mechanism of chloride ions inside the cementitious, and analyzes the current research status and improvement methods of the chloride ion penetration and chloride ion binding capacity of ultra-high-performance concrete.