Mechanics Properties Research Of CFRP-concrete Interface Under Sulfate And Dry-Wet Cycles

The external environment has a great influence on the mechanical properties of CFRP-concrete interface.In a 5% sodium sulfate solution,this paper makes 180 times dry-wet cycle experimente to study interaction of sulfate and dry- wet cycles combined effect on mechanical properties of CFRP- concrete interface.Firstly, makes tensile performance experiment for CFRP specimens at room temperature and test environment.studies the effect of experimental environment on tensile strength, elastic modulus and elongation of CFRP. The results show that: in the test environment durabilityof CFRP is good.Secondly, Double-shear experiments are made for the 30 CFRP- concrete specimens, describes the destruction process, Summes up the failure mode, Preliminary analysis of the mechanism of occurrence of various forms of damage is made. Interfacial peeling carrying capacity double shear test are analyzed.Then, the bearing capacity variation with wet and dry cycles is obtained by analyzing the interfacial peeling carrying capacity of double shear specimens.The strain distribution of CFRP surface of is analyzed, distribution of the interface bond stress is obtained by calculating. Conducts compressive strength tests for the same age concrete block at room temperature and under experimental environment, obtains variation of concrete strength under the two environments. By comparing the compressive strength of the same age concrete under two different environments, analyzes the mechanism of compressive strength.Finally, by analyzing and caparing the existing bearing capacity model and bonding-slip model that are collected, the different characteristics of the model are summarized. Binding experiment data, two kinds of interface capacity model are validated, analyzes the shortcomings of the existing model, proposes improvements.By calculating with the strain of CFRP obtains bond-slip curv of each specimen, analyzes the bond- slip curves in different dry-wet cycles, obtains the two critical control parameters(0s &0?) of bond- slip curves of each specimen. Measured bond- slip curve of each specimen are fitted by using Popovics Model and obtains the fitting parameter(n). On the basis of Popovics model makes regression analysis for each test data to obtain function formula on dry-wet cycles(T) of each parameter and then obtains the CFRP- concrete interfacial bond-slip model into account the combined effect of sulfate with dry-wet cycles under this test condition。...