目前多采用环氧类有机胶粘贴CFRP布加固混凝土结构构件,该胶软化点约为60℃,难以满足耐高温要求.为此,制备了一种可以耐600℃高温的无机胶.用该无机胶粘贴碳纤维布对4根已经历受弯承载能力极限状态的有粘结预应力内置圃钢管桁架混凝土组合梁进行加固,并对加固组合梁进行了受弯性能试验.获得了加固组合梁的正截面受弯承载力和荷载—挠度变形曲线.基于试验数据,提出了考虑原组合梁损伤影响的此类加固组合梁的受弯承载力计算方法,建立了与试验结果吻合良好的刚度计算公式.
Organic epoxy adhesives are usually used in strengthening concrete structures with carbon fiber reinforced polymer (CFRP) sheets.However,due to the low softening points of organic adhesives which are about 60 ℃,concrete structures strengthened with CFRP sheets bonded with organic epoxy adhesives can not meet the heat resisting requirements.In this paper,an inorganic adhesive,which can resist at least 600 ℃ high temperature,was prepared to paste CFRP sheets to strengthen four simply su pported bonded prestressed composite beams encased circular steel tube truss after tultimate limit state,and test on flexural behavior of these four beams was also performed.Moreover,normal section load-bearing capacity of these beams and the cturve load-deflection at mid-span were obtained.Experimental results show that it is feasible to strengthen concrete members with CFRP sheets bonded with inorganic adhesive..Based on the experimental results and theoretical study,computational method of stiffness is proposed for calculating bending rigidity and normal seetion load-bearing capacity of concrete simply supported beams strengthened with CFRP sheets bonded with inorganic adhesive.The formula of bending rigidity calculation was also set up,whose results are in good agreement with testing data.