Comparative fire behavior of geopolymer and epoxy resin bonded fiber sheet strengthened RC beams
Comparative fire behavior of geopolymer and epoxy resin bonded fiber sheet strengthened RC beams
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地质聚合物和环氧树脂粘合纤维板增强 RC 梁的防火性能比较
DOI：
10.1016/j.engstruct.2017.11.027
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发表时间：
2018-01-15
影响因子：
5.5
通讯作者：
Qi, Shu Liang
中科院分区：
文献类型：
--
作者：
Zhang, Hai Yan;Lv, Hao Ran;Qi, Shu Liang
本文介绍了1根钢筋混凝土控制梁和7根纤维布加固钢筋混凝土梁的耐火试验结果，采用土工聚合物和环氧树脂作为粘结剂。监测了这些梁的热响应和挠度随火灾暴露时间的变化情况。比较了碳纤维增强土聚合物(CFRG)加固体系和碳纤维增强聚合物(CFRP)体系在高温下的加固效果。火灾后的试验观测和测量的响应参数清楚地表明，CFRG加固系统在高温下仍然完全有效，因此CFRG加固梁在较长时间(约2小时)的火灾暴露时间内的挠度低于类似荷载水平的相应CFRG加固梁。然而，CFRG加固的梁并没有表现出比CFRP加固的梁更高的耐火性能。为了解释这一结果中的意外趋势，进行了详细的分析，以及大量的材料水平的探索性测试。分析了拉索作用对CFRP和CFRG加固梁的抗火性能的不同破坏机理和附加贡献。进一步的试验结果和分析表明，CFRG加固梁的耐火性能较低的主要原因是隔热层早期脱落和纵向CFRG系统断裂。在土工聚合物与隔热层之间涂覆一层底漆，可防止隔热层早期脱落，从而提高CFRG加固梁的耐火性能(3h以上)。
This study presents results from fire resistance experiments on one RC control beam and seven fiber sheet strengthened RC beams, using geopolymer and epoxy resin as adhesive agents. Thermal response and deflection evolution of these beams with fire exposure time were monitored. The effectiveness of carbon fiber reinforced geopolymer (CFRG) strengthening system and carbon fiber reinforced polymer (CFRP) strengthening system at high temperatures is compared. Post-fire test observations and measured response parameters clearly show that the CFRG strengthening system remains fully effective at high temperatures, and thus CFRG strengthened beams experience lower deflections for longer duration (about 2h) of fire exposure than corresponding CFRP strengthened beam with similar load levels. However, CFRG strengthened beams do not exhibit higher fire resistance than CFRP strengthened beam as anticipated. To explain this unexpected trend in results, detailed analysis, as well as numerous material level exploratory tests were conducted. The different failure mechanisms and additional contribution from cable action so as to enhance fire behavior of CFRP and CFRG strengthened beams were analyzed. Further test results and analysis clearly show that the early falling-off of fire insulation and fracturing of longitudinal CFRG system is the main cause for lower fire resistance in CFRG strengthened beams. When a layer of primer is applied between geopolymers and the insulation, the early falling-off of fire insulation can be prevented, and thus the fire resistance of CFRG strengthened beams can be enhanced (above 3 h).