Effect Of Silica Fume On Mechanical Properties And Durability Of Hybrid Fiber Concrete

Since entering the 21st century,in the process of continuous construction with the development of urbanization,although there are a variety of new materials in the construction field,concrete is still widely used in various buildings in the contemporary engineering field,but ordinary concrete has been unable to meet the needs of modern buildings.Scholars at home and abroad have found that to make up for this shortcoming is to add fiber into concrete,You can optimize its performance.Because silica fume has the characteristics of high volcanic activity and superfine,it is often used to properly fill many internal small pores caused by a series of uncertain factors such as environment,equipment and man-made in the manufacturing process of concrete,so as to improve its structural integrity and increase its working performance.In this paper,silica fume,basalt fiber and polypropylene fiber are added to improve the working performance of concrete.Firstly,the effects of the above three admixtures on the mechanical properties of concrete are studied based on orthogonal test.Then,on the basis of the best content of fiber,the content of silicon powder is divided more finely to evaluate its strength.Finally,the influence of silica fume on the durability of hybrid fiber concrete is tested,and the permeability mechanism,quality corrosion coefficient and strength corrosion coefficient are analyzed.The final conclusions are as follows:(1)In the process of orthogonal test,the compressive and splitting tensile strength of the test block are analyzed.Finally,it is known that the optimal content of compressive strength of the test block is S15%b0.2%P0.2%,and the optimal content of splitting tensile strength of the test block is S10%b0.3%P0.1%.Because the concrete mainly plays a compressive role in engineering practice,the quality of basalt fiber and polypropylene fiber is finally mixed and fixed at 0.2%.(2)Under the optimum content of fiber,when the content of silica fume is 12%,the compressive strength is the largest,28.5mpa,26.4mpa and 53.7mpa for 3D,7d and 28d respectively,and the growth rates of 3D,7d and 28d are 23.9%,26.4%and 21.2%respectively.When the content of silicon powder is 9%,the splitting tensile strength is the largest,which is 3.65mpa,5.32mpa and 7.28mpa on 3D,7d and 28d respectively.The growth rates of 3D,7d and 28d are 23.7%,26.9%and 40.8%respectively.(3)With the addition of three admixtures,the chloride ion permeability of concrete has been greatly improved,and the chloride ion migration channel is blocked under the joint action of the three admixtures.S24b0.2p0.2 has the lowest mass loss at the concentration of 5%,and its mass corrosion coefficient is 0.43%.S21b0.2p0.2 has the lowest compressive strength loss,and its compressive strength corrosion coefficient is 1.8%;S12b0.2p0.2 has the lowest mass loss at 10%concentration,and its mass corrosion coefficient is 0.43%.S9b0.2p0.2 has the lowest compressive strength loss,and its compressive strength corrosion coefficient is 5.0%.Figure[41]table[21]reference[60]...