Study On Mechanical Properties Degradation Law Of Reinforced Concrete Beams Under The Coupling Action Of Coal Mine Environment And Load

Under the coupling effect of coal mine environment and load, the concrete structure appeared different degree of damage and deterioration of, severely damaged part structural members. To grasp the mechanical Properties Degradation Law of the reinforced concrete beams, simulation based on the environment of coal mine, on the subject of previous research achievements based on, change into the component test and simulation environment, adding load coupling factor, of deterioration and damage, deterioration of concrete materials, reinforcement corrosion, not of deteriorated reinforced concrete beams, deterioration and damage deterioration of reinforced concrete beams were relevant research work, main conclusions and innovations are as follows:1.The deterioration of 0-3 deterioration period and damage deterioration of concrete were tested, Draw the deterioration and damage and deterioration of concrete compressive strength, modulus of elasticity in the 0-2 cycle due to carbonation and initial corrosion increased slightly, in the third cycle reduced; carbonation depth in 0-3 cycle continues to grow, basic is the linear change; 0-3 period, elements of deterioration, deterioration of material in the concrete continues to grow, in the third cycle of growth rate increased; microstructure, from changes in hydration and cementitious materials two part analysis the microstructure of concrete in corrosive elements under the action of change;2. Mechanical property test of steel bar with 0-3 deterioration period was carried out, that deterioration and damage deterioration beam of steel corrosion rate in between 0%~5%. With increase of the corrosion rate and reinforced the yield strength and the ultimate strength decreased, but decreased more slowly; with increasing corrosion time, corrosion of the reinforcing steel bar rate increases gradually and in the 0-2 cycles, rebar corrosion rate is slower, in corrosion cycle to the three cycles, the corrosion rates of steel increases;3. Mechanical property test of the non deteriorated beams was carried out, and the deterioration characteristics, failure modes and ultimate loads of the beams were obtained. The experimental results were compared with the theoretical calculation values, and the test results were verified to meet the design requirements;4. Study the 1-3 degradation cycle of deterioration and damage deterioration of beam mechanical performance, come to stop the deterioration period and deterioration of the beams is mainly the deterioration of concrete, reinforced the deterioration of morphology was not obvious; 1-3 deterioration period of test beam failure process and characteristic basically conforms to the damage of the reinforced beam; 1-3 deterioration period and deterioration of beam and injury of inferior of beam cracking load and ultimate load has decreased; the same degradation cycle, damage the cracking load and the ultimate load of deterioration of beam compared to the deterioration of the beam is low;5. With comprehensive 0-3 cycle test beam test results has been deterioration and damage deterioration beam mechanical performance degradation and the corresponding proposed the bearing capacity calculation method in primary corrosive effect, due to the damage and deterioration of beam with crack corrosion factors on two deterioration effect difference is small, therefore, in the primary corrosion condition, the two deterioration beam bearing capacity calculation formula of unity with the corrosion period increases, the test beam stiffness are quite reduced; compared to no deterioration of beam, the deterioration and damage deterioration of reinforced concrete beam ductility deterioration cycle increased and sustained decrease. Deterioration and damage deterioration of reinforced concrete beam displacement ductility coefficient has little difference.