高温水冷后锈蚀钢筋与玄武岩纤维混凝土黏结性能试验研究

Experimental Study on the Bond Performance Between Corroded Steel and Basalt Fiber Reinforced Concrete

  • 摘要: 为揭示高温后喷水冷却与钢筋锈蚀耦合作用下玄武岩纤维混凝土(BFRC)的黏结退化机制,本研究设计并制备了150个偏心拉拔试件,系统考察了玄武岩纤维、锈蚀率及高温水冷对黏结性能的影响。结果表明,600℃后试件的黏结破坏模式发生转变。高温水冷和钢筋锈蚀会显著削弱黏结强度,掺入BF则能有效延缓界面损伤发展。当BF体积分数为0.10%时,400℃高温水冷后BFRC的黏结强度较普通混凝土提高45.7%。灰色关联分析表明,在多因素耦合作用下,高温水冷是影响黏结强度的主导因素,其次为钢筋锈蚀率和BF体积分数。微观试验(SEM-EDS)进一步揭示了BFRC界面过渡区的微观结构及元素变化规律。最后,基于抗压强度数据回归分析,建立了高温水冷与锈蚀耦合作用下BFRC黏结强度计算公式,并提出描述BFRC黏结应力的二阶段黏结-滑移本构模型。

     

    Abstract: To elucidate the bond degradation mechanism of basalt fiber reinforced concrete (BFRC) under the coupled effects of water cooling after elevated-temperature exposure and steel corrosion, 150 eccentric pull-out specimens were designed and fabricated to systematically investigate the influence of basalt fiber (BF) volume fraction, corrosion degree, and water cooling on bond performance. Test results indicate that the bond failure mode of the specimen changes after exposure to 600℃. Both water cooling and corrosion significantly deteriorate bond strength, whereas the incorporation of BF effectively delays the development of interfacial damage. When the BF volume fraction is 0.10%, the bond strength of BFRC after water cooling at 400℃ increases by 45.7% compared with that of ordinary concrete. Grey relational analysis indicates that among the coupled factors, water cooling is the dominant parameter governing bond strength, followed by the corrosion degree and BF volume fraction. Microstructural characterization (SEM-EDS) further reveals the microstructural features and elemental variations within the interfacial transition zone of BFRC. Finally, based on regression analysis of compressive strength data, a predictive formula for BFRC bond strength under the combined effects of water cooling and corrosion is established, and a two-stage bond-slip constitutive model describing the bond stress of BFRC is proposed.

     

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