Study On Durability Of Reinforced Concrete Beams Strengthened With GFRP In Saline And Alkaline Environments

With the extension of service time, reinforced concrete structural members emerged different degree of damage, makes someconcrete member or structure to carries on the reasonable reinforcement and repair to meet the durability requirements. In recent years, with the appearance and development of new materials; because of convenient construction and effective, which makes the fiber reinforced polymer have some advantages in structure reinforcement and repair. And, GFRP has been widely used to reinforce and repair reinforced concrete structures. However, the durability of concrete structures strengthened with GFRP is unclear, relevant research needs to be carried out.With funding from the GuangXi University Scientific Research Foundation of "Experimental study on the durability of reinforced concrete beam reinforced by GFRP in saline and alkaline environment", carry out the experimental study on the degradation law of stress performance and durability about reinforced concrete beam strengthened with GFRP in saline and alkaline environment. The main content includes:1. carry out the experimental study on the durability of GFRP unidirectional fabric and the concrete in saline and alkaline environment, to investigate the degradation law of mechanical properties and to analysis the effect of impregnating resin on the durability of GFRP.2. Through the durability test of 19 pieces of GFRP strengthened reinforced concrete beams under in the different concentration of saline and alkaline corrosion environment, research the influence of durability and mechanical properties of reinforced concrete beam strengthened with GFRP.According to the research, the following conclusions can be obtained:1. The mechanical properties of GFRP decreased obviously, respectively in the saline and alkaline environment after 60 days, alkali influence on durability of GFRP than salt is more serious. Alkali environment have a certain effect on the durability of GFRP coated with resin, however saline environment have no significant effect, it shows impregnating resin effectively protected GFRP.2. In the different concentration of solution, state of stress and protective measures of salt environment after 60 days soaking, the static test shows: increasing the solution concentration and the stress state accelerated corrosion of the strengthened beams in the saline environment; protective measures mitigated corrosion of the strengthened beams in the saline environment. After 60 days of soak in the saline environment, the concentration of solution, the state of stress and the protective measures have certain effect on the durability and mechanical properties of beams strengthened with GFRP.3. The durability and mechanical properties of beams strengthened with GFRP decline is no obvious, because of the short time of soaking. Contrast material test:if the test results of GFRP material durability applied directly to assess the durability of reinforced concrete beams strengthened with GFRP, the results of the evaluation will be on the conservative side.