外贴式CFRP加固钢筋混凝土梁耐火性能研究综述

A LITERATURE REVIEW OF FIRE BEHAVIOUR OF RC BEAMS STRENGTHENED WITH EBR-CFRP STRIPS

CFRP作为一种新型加固材料已有很长一段历史。外贴式CFRP加固技术(Externally Bonded Reinforced,简称"EBR-CFRP")是最常用的CFRP加固技术之一。但由于CFRP对温度较为敏感,基体在温度超过其玻璃化温度(Tg)后发生分解,导致CFRP各项力学性能急剧退化并丧失,这严重影响了该技术在建筑工程领域里的推广和发展。结合近十年关于EBRCFRP加固钢筋混凝土梁耐火性能的相关研究,就CFRP和CFRP-混凝土接触面的高温特性,EBR-CFRP加固梁耐火性能的试验研究、数值分析和预测方法等多个方面的研究成果进行了系统总结,并提出了进一步的研究方向。

CFRP have been used for a long time as a new kind of reinforcing material. Externally Bonded Reinforced（ EBR） is one of the most commonly technologies used in CFRP reinforcement works. But CFRP is sensitive to temperature. When the temperature exceeds the glass transition temperature（ Tg） of CFRP,the matrix used to cure the fibers will soften,which leads to the rapid degradation of the mechanical properties of CFRP. This has seriously affected the development of this technology in the field of civil engineering. For solving the problem,many research was done. This paper presents a review of studies on the high temperature properties of CFRP,CFRP-concrete contact surface and fire resistance of EBR-CFRP strengthened beams. In general,when the temperature reaches about 300 ℃,the matrix in CFRP will melt. The tensile strength of CFRP strips will degrade to 50% of their original strength. However,the CFRP-concrete interface is also sensitive to fire. Without fire prevention,the CFRP strips are easy to spin-off. One of the most effective measures is setting fire insulation at the surface of beams. However,there is no integrated theory of fire-resistance design for CFRP strengthened beams up to now. Recommendations for further research are given at the end of the paper.