Research On Strain Rate Effect Of Concrete Material And Structure Suffering From Sulfate Sodium

Sulfate attack is one of the most widely erosion in the durability of the reinforced concrete structure. Sulfate ions pass into concrete will reaction with cement hydration products, resulting in failure of expansion and chemical degradation, and affecting the mechanical properties of concrete material, finally reducing the safety of the reinforced concrete structure. Therefore, comprehensive understanding the dynamic mechanics performance of sodium sulfate erosion concrete material, building the rate model of sodium sulfate erosion concrete constitutive relationship, designing the process of whole life performance about the reinforced concrete structures is of great significance.By sodium sulfate erosion concrete (6months and8months) of dynamic compression test, combined with previous data, this paper analyzes the strain rate effect of the erosion concrete material. It is shown that the strain rate effect of corrosion6and8months concrete column mechanical performance index is obvious. Different cycle of sodium sulfate erosion concrete compressive strength, elastic modulus and energy absorption capacity reduce rapidly after first increase in same strain rate, the peak strain has been decreased; Performance characteristics response to the erosion, destruction features reflect the strain rate effect.Based on test data, combined with the corresponding standard and research results, building the rate model of erosion concrete material constitutive relation and reinforced rate constitutive model, selecting the parameters of the simulation verification by using ABAQUS software. It is shown that establishing the constitutive model of structural analysis can be used in considering the effect of strain rate. To establish the four layers of the RC frame structure of the pushover analysis. It is shown that:considering the effect of strain rate dynamic nappe method can better assess the seismic performance of structure.By scanning electron microscope (SEM) and X-ray diffraction (XRD) test, investigating the microscopic morphology and the relative content of reactants and products about concrete in different sodium sulfate erosion cycle and depth. It is shown that concrete internal density first increased then decreased along with the corrosion cycle, different depth of the crystal structure is not the same; Same depth and different erosion cycle concrete micro structure and the relative content of calcium hydroxide, gypsum and ettringite change obviously.With reference to the classical theory of similar, building the similarity relation between natural erosion with accelerated test; Based on probability analysis theory, this paper puts forward the service life of the structure calculation process, and gives the statistical characteristics of the sodium sulfate erosion concrete compressive strength; Finally reference relevant empirical formula, giving a preliminary life forecast of the erosion concrete members.