用无机胶粘贴CFRP布加固混凝土板抗火性能试验研究

针对粘贴CFRP布用有机胶软化点过低的问题，研制出600℃时强度不低于常温强度的无机胶。为探索用无机胶代替有机胶粘贴CFRP布提高加固结构抗火性能的可行性，进行了5块用无机胶粘贴CFRP布加固混凝土板的抗火试验。考虑到高温时CFRP布在绝氧条件下强度降低较为缓慢的特点，试验前分别选用厚型隧道防火涂料和厚型钢结构防火涂料对其进行防火保护。试验板先按ISO 834标准升温曲线升温1.5h，再自然降温1.0h。各板底纵向CFRP布经历最高温度为90~300℃，火灾下跨中最大新增位移介于计算跨度的1/438~1/95。经历火灾后，CFRP布完好，无机胶与混凝土板可靠粘贴。试验结果表明:采用无机胶粘贴CFRP布加固混凝土板，厚型隧道防火涂料和厚型钢结构防火涂料均能达到对CFRP布进行控温和绝氧的目的，前者防火效果明显优于后者；用无机胶粘贴CFRP布加固混凝土板采用防火涂料保护后，火灾下和火灾后CFRP布与混凝土板均可有效共同工作。

Experimental research of fire performance on reinforced concrete slabs strengthened with CFRP sheets bonded with inorganic adhesive

Softening temperature of organic epoxy adhesives used to bond CFRP sheets is too low, so an inorganic adhesive is developed, the strength of which at 600℃ is no less than that at room temperature. To investigate the feasibility that the inorganic adhesive takes place of organic adhesive in bonding CFRP sheets, a fire test of five reinforced concrete slabs strengthened with CFRP sheets bonded with the inorganic adhesive was carried out, aiming to improve fire performance of strengthened concrete structures. Considering the strength of CFRP sheets under non-oxygen condition was hardly reduced at high-temperature, the thick-typed fireproofing coating for tunnel (TFCT) and thick-typed fireproofing coating for steel structure (TFCSS) were selected to protect CFRP sheets. Specimens were exposed to fire in according to ISO 834 standard fire curve for 1.5 hours, then the test datum were continuously recorded for another hour after ceasefire. The highest temperature of CFRP sheets varied from 90℃ to 300℃, and displacements at mid-span reached 1/438-1/95 of the actual span. CFRP sheets were discovered intact after fire and were tightly bonded on the concrete slabs by the inorganic adhesive. The test results indicate that, TFCT and TFCSS can decrease temperature of CFRP sheets and isolate oxygen from CFRP sheets, TFCT is superior to TFCSS for the fire performance of reinforced concrete slabs strengthened with CFRP sheets bonded with the inorganic adhesive. Under the protection of the fireproofing coating for this kind of slabs, CFRP sheets work well in cooperation with concrete slabs in fire and after fire.