Experimental Study On Durability Of Basalt Fiber Reinforced Concrete Under Sulfate Attack

The region of China is wide and sulphate salt is widely distributed.Most of the sulphate exists in the environment of lakes,oceans and saline alkali land.The influence of sulfate erosion on concrete buildings is complex and harmful,which affects the durability of the building and causes the life of the building to be shortened seriously.Some concrete buildings suffer from the corrosion of sulphate and jeopardized the safety of the building itself.The reduction of the duration of the use of the building caused by sulfate corrosion has become one of the research topics in the world,and has received the attention of the civil engineering people.As a improvement of ordinary concrete,basalt fiber reinforced concrete has been widely used in engineering because of its high bearing capacity,good impact resistance,corrosion resistance,reliable chemical stability,and excellent anti seepage and frost resistance.Basalt fiber reinforced concrete will also be eroded by corrosive medium during the working process.The durability of basalt fiber reinforced concrete can not be ignored.The corrosion of sulfate radical ions to basalt fiber concrete in sulphate environment is the main content of this paper.The study of the transmission law and corrosion mechanism of sulfate ion in basalt fiber concrete is of great significance to further enhance the durability of basalt fiber concrete.In this paper,the porosity of basalt fiber reinforced concrete under sulphate erosion is studied by combination of theoretical analysis and test,macro test and microanalysis,and the development of microscopic cracks on the surface of the surface and the internal pore change,the surface of the coagulant soil and the concentration of sulfate ions in the inner surface of the concrete are investigated by the method of the macroscopic and microcosmic analysis.Based on the compressive strength of concrete and basalt fiber reinforced concrete,a concrete damage prediction model and a sulfate ion concentration prediction model are established.The main contents and results are as follows:Through the study of the moisture reduction,the change of water absorption,the age of erosion and the resistance to sulfate corrosion of the basalt fiber concrete,the test results show that the moisture reduction of concrete with the addition of basalt fiber 0.1%is the least,and the water absorption rate is the lowest.The microscopic observation of the pore cracks on the interior and surface of the concrete test block showed that the number and size of pores in the concrete with basalt fiber addition were reduced.Compared with various types of concrete test blocks,it was found by scanning that basalt fibers were added.The porosity of 0.1%concrete specimens is the smallest.Different compressive strength tests for different basalt-mixed concrete specimens during different corrosion times were conducted.The effects of different fiber blending amounts,different etching time,and the incorporation of fly ash on the compressive strength of the concrete were investigated.Comprehensive analysis,the test results show that:when adding basalt fiber content of 0.1%to concrete specimens,the compressive strength of concrete is most effective to enhance the effect.The ion concentration measurements in different parts of basalt fiber reinforced concrete have been studied.The experimental data show that the ionic solubility gradually decreases from the outside to the inside of the concrete test block,while the amount of reduction is different between different types of test blocks,and the ion concentration Experiments show that when the added fiber content is 0.1%,the corrosion resistance of the concrete is improved to some extent.The corrosion resistance coefficient is derived from the data obtained from the corrosion resistance test,and the relationship between the corrosion resistance coefficient and the compressive strength is established.According to the corrosion resistance coefficient,the damage of concrete test pieces due to the different corrosion time and the different fiber content,the corresponding damage model is established.In this paper,the law of water absorption,crack and pore expansion,strength degradation and ion diffusion of sulfate root are obtained in this paper.According to the conclusion and all kinds of experimental phenomena,it is suggested that the mixing amount of best basalt fiber is 0.1%.