Durability Research Of Concrete Strengthened With CFRP

The technology which strengthens concrete structure with carbon fiber-reinforced polymer(CFRP)is emerging, and has long term potential. But because of the immobilization of buildings,the buildings strengthened with CFRP will still experience all kinds of environmental effect.Then these problems such as the durability and longevity of these buildings have attracted someengineers' attention. Combined with science and technology plan item of Jiang Su Province'sconstruction system-the study about application of Reinforcement Technology of ConcreteStructures Using Carbon Hybrid Sheet in residential engineering whose code is JS200438, thispaper studies the performance of concrete structures under different environmental conditionsstrengthened with carbon fiber sheet.On the basis of referring a great deal of data, this paper designs rectangular concretecolumns and concrete cubes which consist of two strength grades-C25 and C50, respectively.Rectangular concrete columns are used to test the strength and deformation of concrete columnsstrengthened with CFRP when being compressed, while concrete cubes are used to test the bondbetween concrete and CFRP when being tensed. In this paper these environmental conditionssuch as water environment, acid environment (pH=4) , alkaline environment (pH=12) ,carbonation environment and natural environment are considered, while the time quantum is 14days and 56 days. At last, the finite element software ANSYS is used to simulate the behaviorof concrete columns strengthened with CFRP when being compressed, and to simulate thecounterpart behavior of concrete columns after acid environmental effect.As far as rectangular concrete columns strengthened with CFRP are concerned, thestrength after acid environmental effect is minimum, and as far as concrete cubes are concerned,the bond between concrete and CFRP is minimum, too. Of the destruction types of concretecubes when being tensed the bond destruction type is seen to occupy the maximum proportionwhen the environmental conditions are water environment, acid environment, alkalineenvironment, etc. Freeze-thawing circle has not very significant effect on the strength ofrectangular concrete columns strengthened with CFRP. Comparatively, freeze-thawing circlewill lead to the more immediate decline of bond of concrete cubes than the strength ofrectangular concrete columns strengthened with CFRP, but post-gradient is smaller than the pre-gradient.The software ANSYS is used to simulate the behavior of concrete columns strengthenedwith CFRP when being compressed, and the results show that the section at the mid 100mms ofcolumn height is critical, furthermore destruction take place at the angle of theabove-mentioned section. The software ANSYS is used to simulate the counterpart behavior ofconcrete columns after acid environmental effect, and the stress-strain curve show that this kindof column is more ductile than above-mentioned column.