Investigation On High Temperature Performance Of Concrete Columns Strengthened With Basalt Fiber Sheet

As its low cost, thermostability, low thermal conductivity, and high extensibility,continuous basalt fiber (CBF) is gaining increasing interest in recent years. However, thereare not that much research results of the properties of BFRP and BFRP strengthened membersat room and high temperature. What is more, epoxy adhesives of poor fire performance arealways used during the strengthening of structure, which may lead to large potential safetyhazard to the strengthen structure without fire protection. In this paper, some research of theproperties of the BFRP strengthened reinforced concrete (RC) columns at room and hightemperature are conducted, and the research details are as follows:Nonlinear finite element analysis of the basaltic fiber sheet (BFS) strengthened RCcolumns at room temperature is preceded. The effective strengthening method is proposed.Mechanical proterties tests of BFRP and CFRP sheets at room temperature and after hightemperature are done, and the changing law with time and temperature of the mechanicalproperties of these two sheets are got. The test results show that because of the poor fireperformance of the matrix material and adhesives, there is no obvious advantage of the fireperformance of the normal BFRP.In order to improve the fire performance of the BFS strengthened RC column, twomethods are adopted, of which one is to use outside fire retardant coating, the other isdeveloping geopolymer to replace epoxy adhesives. Nonlinear finite element analysis of theBFS strengthened RC columns with fire retardant coating at high temperature is preceded.The impact of the fire protection layer thickness on the strengthen effect is studied, and thesuggest value of the fire protection layer thickness of the BFS RC columns is proposed. Sometests are done to investigate the influence of curing condition and water to binder ratio on theperformance of geopolymer materials and a fine geopolymer is got. After that double sheartest is conducted, and the variation law of cohesiveness of geopolymer with temperature is got.A textual study on the mechanical property of geopolymer at high temperature is madecompared with epoxy adhesives.