Experiment And Research On Mechanical Properties Of Autoclaved Steel Fiber Fly Ash Brick And Block In Long Age

In order to improve the mechanical properties, adding the steel fiber into autoclaved fly ash brick and block. Studies have shown that the performance of autoclaved steel fiber fly ash brick and block improved when comparsion with the ordinary brick and block. Steel fiber embodies the characteristics that enhanced resistance to crack. Considering the application in the partical engineering, the article studied the basic mechanical performance of autoclaved steel fiber fly ash brick and block in long-age and contrasted the result of earily age. On the basis of the tests, recorded and analysised the result and explored the reason of the test results in the same time. Finally, evaluated the performance and durability of autoclaved steel fiber fly ash brick and block in a certain degree.According to the specification, tests of compressive strength, flexural strength and frost resistancetests were conducted for autoclaved fly ash brick and autoclaved steel fiber fly ash bricks with steel fiber volume content of0.4%,0.6%and0.8%respectively when these brick were cured1000d in natural environment. The compressive strength test were also conducted of autoclaved steel fiber fly ash block with the0.6%volume content of steel fiber.As the matrix, the performance of fly ash brick will defect and influence the mechanical performance of autocalved steel fiber fly ash birck in long age. The average compressive strength of the four kinds of autoclaved steel fiber fly ash brick were8.7MPa,8.9MPa,9.4MPa and8.5Mpa in the1000d age and the strength has increased by7.5%and8.9%with steel fiber volume content of0.4%and0.6%. The average flexural strength of the four kinds of autoclaved steel fiber fly ash brick were1.24MPa,1.44MPa,1.72MPa and1.54Mpa in the1000d age and the strength has increased by20%,30%and23%with steel fiber volume content of0.4%,0.6%and0.8%. The results shows that reasonable steel fiber volume content can still enhance the autoclaved fly ash brick in long age and the enhancement effect of flexural strength is better than compressive strength.The freezing and thawing test shows that the mass loss ratio of four kinds autoclaved fly ash brick all within20%,the result can well meet the standard requirement. But, the decrease amplitude of the strength was increased by freezing and thawing shows that the frost resistance of brick should be enhanced. The average compressive strength of0.6%volume content hollow block did not loss and the failure process also with the same when compared with the result of28d. The block has a high density and the steel fiber without serious corrosion. The autoclaved steel fiber fly ash hollow block shows its excellent durability and appicability.To observe the damage form of specimens, reasonable volume of steel fiber still can improve the integrity and damage form of autoclaved fly ash brick in long age.0.6%volume content of steel fiber is reasonable and available. The corrosion of steel fiber is the main reason to affected the durability of autoclaved steel fiber fly ash brick and it’s the reason that why the specimen with0.8%volume content shows a worse performance.