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高温下CFRP筋及其粘结型锚固系统的力学性能

Mechanical properties of CFRP bar and bond-type anchorage system exposed to elevated temperature

    摘要
  • 摘要: 为明确高温下碳纤维增强复合材料(Carbon fiber reinforced polymer，CFRP)筋及其以活性粉末混凝土(RPC)为粘结介质的粘结型锚固系统的力学性能，以处理温度为试验参数，完成了12个筋材试件的高温轴拉试验和8个锚固性能试件的高温拉拔试验。揭示了处理温度对高温下CFRP筋及其粘结型锚固系统力学性能的影响规律，建立了适于分析高温下CFRP筋轴向拉伸性能、以RPC为粘结介质的粘结型锚固系统粘结强度及临界锚固长度的实用计算公式。结果表明：对于筋材轴拉试件，100℃、210℃和300℃下筋材的抗拉强度、弹性模量较常温试件分别下降了(2.3%、11.4%)、(29.8%、35.6%)和(40.9%、45%)，高温下筋材的弹性模量较抗拉强度受处理温度的影响更为显著；100℃、210℃和300℃下筋材的极限拉应变较常温试件分别增大了18.5%、17.3%和14.8%，高温下筋材的极限拉应变随处理温度升高而呈先增大后减小的变化趋势；对于锚固性能试验，试件的粘结强度随处理温度升高而线性衰减，处理温度为100℃、210℃与300℃试件的粘结强度较常温试件分别下降了20.4%、52.6%和85.1%。文中所建立的高温下CFRP筋与粘结型锚固系统力学性能的实用计算公式均具有较高精度。

     

    Abstract: To determine the elevated-temperature mechanical properties of carbon fiber reinforced polymer (CFRP) bar and its bond-type anchorage system with bonding agent of reactive powder concrete (RPC), the axial tensile tests and pull-out tests with parameter of treatment temperature were conducted on 12 CFRP bar specimens and 8 anchorage performance specimens exposed to elevated temperature, respectively. The effects of elevated temperature on the mechanical properties of CFRP bar and its bond-type anchorage system under high tempera-ture were uncovered, and the practical formulas were developed for determining the axial tensile properties of CFRP bar, the bond strength and the critical anchorage length of the bond-type anchorage system with bonding agent of RPC exposed to elevated temperature. The results demonstrated that the tensile strength and elastic modulus of axial tensile specimens exposed to the elevated temperature of 100℃, 210℃ and 300℃ decreased by (2.3%, 11.4%), (29.8%, 35.6%) and (40.9%, 45%), respectively, compared to the specimen under room temperature. The effect of elevated temperature on the elastic modulus of CFRP bar exposed to elevated temperature was more significant than the tensile strength. The ultimate tensile strain of axial tensile specimens exposed to the elevated temperature of 100℃, 210℃ and 300℃ increased by 18.5%, 17.3% and 14.8%, respectively, compared to the specimen under room temperature. With the increase of the elevated temperature, the ultimate tensile strain of CFRP bar increased firstly and then decreased. The bond strength of the anchorage performance specimens decreased linearly with the increase of the elevated temperature. Specifically, compared to the specimen under room temperature, the bond strengths of the specimens exposed to the elevated temperature of 100℃, 210℃ and 300℃ decreased by 20.4%, 52.6% and 85.1%, respectively. The practical formulas with high accuracy for determining the mechanical properties of the CFRP bar and bond-type anchorage system exposed to elevated temperature were developed in the present study.

     

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