| As a lightweight and high-strength reinforcement material, carbon fiber-reinforced polymer (CFRP) has received widespread use in structural reinforcement, repair, and rehabilitation. Currently epoxy adhesive is used to form the bond between CFRP and concrete, but its mechanical and bond properties deteriorate gradually when exposed to temperatures higher than 60℃. This experimental program was done using high temperature resistance inorganic adhesive MOC (Magnesium Oxychloride Cement).Instead of organic adhesive, appropriately insulated CFRP-strengthened concrete slabs using inorganic adhesive MOC can provide adequate fire performance and resistance.Compared with organic adhesive, though the bending strength of MOC inorganic adhesive is lower, it has more excellent performance in other mechanical properties in the room temperature. Firstly, this paper addressed some of experiments relevant to the mechanical properties of MOC inorganic adhesive at high temperatures. The test results showed that the compressive strength of the MOC adhesive was not adversely affected within 200℃. When at 350℃, the compressive strength of the MOC adhesive was approximately 52% of that in room temperature. Upon evaporation of all of the water at 400℃, the MOC adhesive remained little compressive strength. In addition, more experimental studies were conducted for the MOC test samples with 10mm thickness fire protection at high temperature. Based on results from these samples, it was found that high compressive strength and bending strength still existed in these inorganic MOC samples at 400℃which was approximately 5 times higher of those of MOC without fire protection. The results of these experiments imply that effective fire protection can significantly reduce the loss of compressive strength of inorganic MOC. Also a static test to investigate the performance of CFRP-strengthened concrete slab using inorganic adhesive MOC at the room temperature was conducted. This study demonstrated that the ultimate bearing capacity of slab with inorganic adhesive MOC can be increased by 10%. Additionally four CFRP-strengthened concrete simple slabs were cast in the high temperature, one using epoxy resin and the other three using inorganic adhesive MOC. The slabs were then tested in the fire. The data of temperature distribution and mid-span deflection of slabs were recorded during the whole process. The outcome of the test implied various fire resistance of these four slabs. According to the mid-span deflection, without considering the impact of burst of the slab strengthened with CFRP sheet by inorganic adhesive with 30mm thickness fireproof coating, the slab strengthened with CFRP sheet by inorganic adhesive with 30mm thickness fireproof coating performed best in the fire, followed by the slab strengthened with CFRP sheet by inorganic adhesive with 15mm thickness fireproof coating, the slab strengthened with CFRP sheet by inorganic adhesive without fireproof coating and the slab strengthened with CFRP sheet by epoxy resin with 15mm thickness fireproof coating. When comparing the different thickness of fire protection, the fire resistance of CFRP-strengthened concrete slabs with fire protection was better than those without fire protection. When the adhesives used of pasting CFRP sheets after heating failure, the CFRP sheet was separated into a series of tows-like cloth hanging on the plate bottom in the fire. The destruction time of the CFRP sheet which was coated with 15mm thick fire-resistant coating was pasted with epoxy resin was about 27min-30min. The CFRP sheet without fire protection would be destroyed within few minutes. It has significantly improved. In addition, in the early stage of experiment, fire endurance of slabs strengthened with CFRP sheet by inorganic adhesive coated with 30mm fire protection was better than those with 15mm fire protection. As severe cracks were happened in the later stage of the slab strengthened with CFRP sheet by inorganic adhesive with 30mm thickness fireproof coating experiment, this result was not obvious. In general, The fireproof coating could significantly improve its fire resistance for the concrete slab strengthened with CFRP sheet by inorganic adhesive. Increasing the thickness of fire-resistance coating could better improve its fire resistance. However, the large thickness of the fireproof coating was vulnerable to burst. It should be taken appropriate measures to reduce the influence of burst in setting large thick fireproof coating.
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