复杂环境及荷载共同作用下CFRP加固高强钢筋-混凝土梁受力性能试验

为研究冻融循环、湿热环境、持续荷载等因素共同作用对碳纤维增强复合材料（CFRP）加固高强钢筋混凝土梁耐久性的影响，制作了15根CFRP加固钢筋混凝土梁。对荷载和环境因素耦合作用下CFRP加固钢筋混凝土梁的结构性能进行了试验研究和理论分析。结果表明:湿热环境和冻融循环都会对CFRP加固钢筋混凝土试件产生不同程度的影响；采用CFRP加固钢筋混凝土梁将增加试件刚度，但环境作用使得黏结界面劣化，从而使加固试件刚度降低，变形增大；持续荷载会加速环境对CFRP加固钢筋混凝土试件的劣化速度，并且随着荷载等级的增大，影响越来越明显；相同环境作用下，持续荷载使得试件极限承载力降低，并且随着持续荷载的增加，试件承载力降低加快；经受150次冻融循环、湿热1 000 h作用时，持续荷载等级为30%，60%试件的承载能力分别下降2.5%，10.2%，持续荷载会加速劣化加固混凝土试件的抗弯性能；温度40°、湿度98%的湿热环境下500 h比冻融循环150次对试件劣化程度产生的影响更为显著。

Mechanical Performance Test of High-strength Reinforced Concrete Beam Strengthened by CFRP Under Combined Action of Complex Environment and Loading

In order to study the effects of freeze-thaw cycles, hot and humid environment and sustained loads on the durability of high-strength reinforced concrete beams strengthened with carbon fiber reinforced polymer (CFRP), a total of 15 reinforced concrete beams strengthened by CFRP were fabricated. The structural performances of reinforced concrete beams strengthened with CFRP under the interaction of load and environment were studied and theoretically analyzed. The results show that both hot and humid environment and freeze-thaw cycles have certain degrees of influences on reinforced concrete beams strengthened by CFRP. The effect of environment on the bonding interface deteriorates, and the stiffness of strengthened specimen decreases and the deformation increases. Sustained load will speed up the degradation of reinforced concrete beams strengthened by CFRP in coupled external environment, and the higher the sustained load increases, the more obvious the degradation effect is. Under the same environment, the ultimate bearing capacity of specimen is reduced, and the bearing capacity of specimen decreases as the continuous load increases. Under the action of 150 freeze-thaw cycles and 1 000 h continuously in hot and humid environment, the bearing capacities of specimens under 30% and 60% load grades decrease by 2.5% and 10.2% respectively. The continuous load will accelerate the bending resistance of damaged concrete specimens; the degradation effects on specimens of 500 h continuously in the environment with temperature of 40 ℃, humidity of 98% are larger than those of 150 freeze-thaw cycles.