The HVFAC Anti-Abrasion Properties Based On Fractal Theory

Fly ash is a very small particles that can flow in the air. It is an industrial waste which has large annual wmissions and serious environmental pollution.However,the fly ash is as an admixture which was applied to the concrete.It not only improved the overall performance of concrete,but also reduce the burden on the environment.The high volume fly ash concrete is applied to the concrete structure which has the greatest degree substitution of cement and good economic,social and environmental benefits.In this paper,the large volume fly ash concrete has a performance test of abrasion in a project in Ningxia.We study the effcets of different fly ash concrete abrasion performance through the experiment and analyse andresearch the reslts of experiment by the fractal box counting method.Finally,We recommend the application of engineering best concrete mix.In this study,the following main conclusions:(1)When the content of the fly ash in the concrete is less than 50%,the compressive strength of concrete increases with the augment of the content of fly ash;When the content of the fly ash in the concrete is more than 50%, the compressive strength of concrete decreases with the augment of the content of fly ash; The compressive strength of the 60d age of the high volume fly ash concrete is greater than the compressive strength of the 28d age of the high volume fly ash concrete.(2)When the content of the fly ash is less than 50%,with the increasment of fly ash ,the wearing rate of the concrete decreases; When the content of the fly ash is greater than 50%,ith the increasment of fly ash, the wearing rate of the concrete increasment;The wearing rate of the 28d age concrete is greater than the wearing rate of the 60d age concrete.(3)Mixed with 1% suoperplasticizer and 0.6/million air-entraining agent in the concrete,the concrete compressive strength and abrasion strength are improved to some extent.(4)When the content of the fly ash is less than 40%,with the increasment of fly ash,the fractal dimension is decreasing,the abrasion strength of the concrete is increasing; When the content of the fly ash is greater than 40%, with the increasment of fly ash, the fractal dimension is increasing, the abrasion strength of the concrete is reducing.(5)The concrete of the 28d age:When the fly ash is 40%,the fractal dimension is 2.0277,the maximum scour strength of concrete; The concrete of the 60d age: When the fly ash is 40%,the fractal dimension is 2.0212,the maximum scour strength of concrete;The fractal dimension of the 28d age concrete is greater than the fractal dimension of the 60d age concrete.(6)When the content of the fly ash is from 40%to 60%,the fractal dimension of the wearing surface of the specimen is in between 2.0250~2.0290,the abrsion strength of the concrete is appropriate.(7)It is recommended to use the best ratio of the high volume fly ash concrete,it is 1:2.13:3.42:0.65(W:C:F:W/B),and the fly ash content is 50%(the excess factor is 1.3).