Fire-Resistance Performance Study Of RC Slabs Strengthened With CFRP Sheets

The technology of CFRP(carbon fiber reinforced polymer)reinforced and repaired RC structure is more and more widely applied in the field of building structural strengthening,its light weight,high strength,corrosion resistance,and many other advantages to become the important features of the widely used.At present,the ordinary epoxy resin type organic adhesives are often used to paste CFRP sheets,but its glass transition temperature is only 100?,and under high temperature of fire,it would lose the ability of bond,and lead to reinforcement function failure of CFRP,the fire resistance of reinforcement member is far lower than the regulations on fire prevention design specification.The fire performance which organic adhesives stick CFRP to reinforced concrete structure is far less than the original fireproof property,and it becomes the barrier of using CFRP in the building structure.Therefore,the problem that improves the fireproof performance of carbon fiber reinforced concrete structures should be solved immediately.In this paper,based on the research results of domestic and overseas about temperature field of RC slabs with carbon fiber under high temperature,and this paper adopts numerical simulation method to analyze the temperature field of RC slabs with carbon fiber.The paper's main job content is as follows:1.Using the method of numerical analysis can deduce the one-dimensional heat conduction finite element equations of RC slabs.Analyzing the RC slabs' temperature field under the single fire of the bottom of the slabs,and doing comparison with the test data on the same conditions.The results show that the numerical simulation results are similar to experimental data,the numerical model is reasonable and reliable,and can be used to simulate and analysis temperature field of the RC slabs.2.Summarizing the criteria of fire endurance of the RC slabs,and combining with the results of numerical simulation,making some comparisons to the fire resistance of the RC slabs which is unreinforced under the different criteria.3.Analyzing the temperature field distribution of the RC slabs on the ISO-834 standard fire heating curves,discussing the relationship between the fire resistance of the RC slabs and the thickness of concrete cover thickness or the thickness of the slabs.The results show that the fire resistance has a significant increase with the increase of the thickness of concrete cover,but the thickness has few effect on the fire resistance of the RC slabs.4.Making a contrast analysis to the temperature field distribution of the RC slabs unreinforced and with CFRP reinforced.The results show that the fire resistance of the RC slabs with CFRP which is no fire protection reinforced is very low(about 5 min),is far less than the fire resistance of the original RC slabs.5.Studying the effect of the thickness of thick steel structure fireproofing coating on the fire endurance under the standard fire environment.The results showed that the fire endurance of RC slabs with CFRP will prolong while the thickness of fire-proof painting increases.While the thickness is 30mm,organic adhesives lose efficacy after 67min”s heating,the fire endurance of member satisfy the secondary fire resistance rating about 1 hour,while the thickness is 40mm,organic adhesives fire endurance can run into 113min,and it can satisfy 1.5 hours' fire resistance rating.The research results of this dissertation about temperature field analysis and fire resistance of the RC slabs with CFRP can provide some references for fire protection design and construction of strengthening engineering.