The Influence Of Corrosion Environment On The Durability Of Concrete Against Sulfate Attack

The structure of hydraulic structures in the Three Gorges Reservoir area is subject to salt erosion in a complex environment.These erosion effects make the concrete structure ineffective or even destroyed.Therefore,it is necessary to study the durability of concrete against sulfate erosion in the complex environment.Basalt fiber reinforced concrete has good mechanics and durability.At present,the research on sulfate erosion of basalt fiber concrete is not in-depth.In this paper,the durability test of coagulation specimens with different basalt fiber content under sulfate and chloride corrosion environment is carried out.The research content and main conclusions are as follows:(1)The influence of corrosive environment on the appearance of basalt fiber concrete specimens was studied.Under the natural erosion environment,the appearance of the specimens changed little;under the dry-wet cycle erosion environment,the appearance of the specimens changed significantly;under the same erosion environment,the appearance of the basalt fiber concrete specimens changed less than that of the ordinary concrete specimens.(2)The influence of corrosive environment on the quality of basalt fiber concrete specimens was studied.As the erosion time increases,the mass of the specimen first increases and then decreases.In this test,the quality damage of the basalt fiber concrete specimens after erosion is lower than that of the ordinary concrete specimens,and it is concluded that the appropriate amount of basalt fiber mixed in can enhance the sulfate corrosion resistance of the concrete.(3)The influence of basalt fiber content and erosion environment on the mechanical properties of concrete is studied.Before erosion,the proper amount of basalt fiber can improve the mechanical properties of concrete;under different erosion environments,with the increase of erosion time,basalt fiber concrete The ultimate compressive strength of the specimens all showed a trend of first increasing and then decreasing.In the later stage of erosion,the joint erosion of sulfate and chloride under dry and wet cycles has the most serious impact on the compressive strength of the specimen.(4)The change law of elastic wave velocity before and after the action of different corrosive environments and the relationship between elastic wave velocity and compressive strength are studied.With the same basalt fiber content,the elastic wave velocity first increases and then decreases as the erosion time increases;there is a quadratic function relationship between the elastic wave velocity and the compressive strength.(5)The changes in the water content of basalt fiber concrete under long-term immersion and dry-wet cycles are studied.The results show that the incorporation of a proper amount of basalt fiber reduces the internal pores of the concrete,and the concrete structure is more dense and solid,which improves the concrete’s resistance to sulfate erosion.Performance,the 0.1% basalt fiber content in this test has the greatest improvement in the compactness of the concrete.(6)The SEM electron microscope experiment found that the basalt fiber is more evenly distributed inside the concrete and has good compatibility with the concrete;the basalt fiber has a bonding effect on the concrete matrix,making it difficult to crack and damage.After the erosion,as the erosion products continue to increase,the internal stress increases and the microstructure is destroyed,which eventually leads to concrete deterioration.