氯盐侵蚀-外加电流下导电TRC抗裂性能及提升技术研究

Research on the crack resistance and improvement technology of conductive TRC under chloride salt corrosion and impressed current

  • 摘要: 为改善氯盐侵蚀-外加电流下导电纤维编织网增强混凝土(Textile Reinforced Concrete, TRC)的抗裂性能,本文首先通过四电极法提出了一种通过复掺碳纤维和石墨的导电细粒混凝土,并通过四点弯曲试验研究了细粒混凝土厚度、纤维编织网层数和内嵌碳纤维增强复合材料(Carbon Fiber Reinforced Polymer,CFRP)筋对氯盐侵蚀-外加电流下导电TRC抗弯性能的影响。研究表明,随着养护龄期的增加,细粒混凝土的电阻率逐渐上升;复掺碳纤维和石墨可有效降低细粒混凝土的电阻率,且电阻率随着碳纤维和石墨掺量的增多逐渐降低;增大细粒混凝土厚度对TRC抗弯性能提高幅度较小,而增大纤维编织网层数和内嵌CFRP筋均可有效改善TRC的裂缝分布特征,提高导电TRC的抗裂和抗弯性能;基于基本假定,结合试验数据和截面受力分析图,建立了氯盐侵蚀-外加电流下的TRC四点弯曲承载力计算模型。

     

    Abstract: To improve the cracking resistance of conductive Textile Reinforced Concrete (TRC) under chloride salt corrosion and impressed current. In this paper, a conductive fine-grained concrete by compounding carbon fibers and graphite was firstly proposed by the four-electrode method, and the effects of fine-grained concrete thickness, textile layers, and embedded CFRP bars on the flexural performance of conductive TRC under chloride salt corrosion and impressed current were investigated by four-point bending test. It is shown that the electrical resistivity of fine-grained concrete gradually increased with increasing age of curing. The dual incorporation of carbon fiber and graphite can effectively reduce the resistivity of fine-grained concrete, and the resistivity of fine-grained concrete decreases gradually with the increase of carbon fiber and graphite mixing. Increasing the thickness of fine-grained concrete has a relatively small effect on the flexural performance of TRC. While increasing the number of layers of textile and embedded CFRP bars can effectively improve the crack distribution characteristics of TRC and improve the crack resistance and bending resistance of conductive TRC. Based on basic assumptions, combined with experimental data and cross-sectional stress analysis diagrams, a calculation model for TRC four point bending bearing capacity under chloride salt corrosion and impressed current is established.

     

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