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为了提供更准确的关于GFRP筋混凝土梁长期粘结耐久性影响规律的试验数据及设计理论指导,基于实际混凝土梁带工作裂缝持续受载的工作状态,通过对带工作裂缝GFRP筋混凝土梁加速老化后进行三点偏载试验,研究分析了工作裂缝对GFRP筋混凝土梁受室外环境、水溶液、60℃的碱性溶液等3种不同环境侵蚀90、180、270d后的粘结耐久性影响,并提出关于不同滑移量计算粘结应力的理论计算方法;还依据试验数据及计算理论确定了环境作用270d后各工况下的最大粘结应力。研究结果表明:带工作裂缝GFRP筋混凝土梁在碱性环境作用270d后,滑移荷载损失高达38.5%,挠度值增加46.3%,最大粘结应力损失高达59.4%;未带工作裂缝GFRP筋混凝土梁在任何侵蚀环境条件下,其滑移荷载及挠度值变化比例均小于带工作裂缝的GFRP筋混凝土梁;最大粘结应力值均大于带工作裂缝GFRP筋混凝土梁,且损失比例均小于带工作裂缝的GFRP筋混凝土梁;室外环境、水溶液、碱性溶液这3种环境中,碱性溶液对GFRP筋混凝土梁的粘结耐久性能影响最为明显,且工作裂缝较大程度地加大了各种环境对GFRP筋混凝土梁粘结性能的劣化影响。
In order to provide more accurate test data and design theory guidance on the long-term bond durability of GFRP reinforced concrete beams, based on the continuous load working condition of the actual concrete beam work cracks, through accelerated aging of GFRP reinforced concrete beams with working cracks, After three-point partial load test, the effect of working cracks on the bonding durability of GFRP reinforced concrete beams under 90, 180, 270 days after exposure to outdoor environment, aqueous solution, alkaline solution at 60 ℃ was studied. The theoretical calculation method for calculating the bond stress with different slippage was put forward. The maximum bond stress under various conditions after 270 days was also determined according to the experimental data and calculation theory. The results show that the GFRP reinforced concrete beam with working crack has a maximum of 38.5% slip load, 46.3% flexural loss and 59.4% maximum bond stress loss after 270 days of alkaline environment. GFRP reinforced concrete beam without working crack Under any corrosive environment, the change ratio of the slip load and deflection is less than that of the GFRP reinforced concrete beam with working crack. The maximum bond stress is larger than the GFRP reinforced concrete beam with working crack, and the loss ratio is less than that of the working crack Of GFRP tendons and concrete beams. In the three environments of outdoor environment, aqueous solution and alkaline solution, the alkaline solution has the most obvious effect on the bond durability of GFRP reinforced concrete beams, and the working cracks have greatly increased the various environments Effect of Degradation on the Bonding Performance of GFRP Reinforced Concrete Beams.