Papers by Author: Min Bai

Abstract: In order to study various factor affecting durability of steel fiber reinforced concrete (SFRC), basic experimental research that combine the action of freezing-thawing cycles and deicing salt to SFRC was conducted. In the experiment, the volume fraction of steel fiber and number of freeze-thaw circulation are taken as variable parameter. Based on the different numbers of freeze-thaw circulation, weight losing of SFRC, splitting strength and the dynamic modulus of elasticity were measured. Furthermore, the reinforced mechanism of the SFRC under the action of freeze-thaw was analysed. The test results show that after adding a certain amount of steel fiber to the concrete, cracks in concrete at early stage are effectively prevented and the permeability of concrete is obviously reduced, thus the durability of concrete is improved. The reinforced actions of steel fiber on splitting strength of concrete are notable and the influence of steel fiber volume fraction on the frost-resisting property is obvious. On the contrary, the negative effects of steel fiber with high volume fraction on the splitting strength of concrete exist. The best performance of SFRC can be got when the steel fiber quantity is 1.5%.

Abstract: In recent years, the concrete material subject to chloride corrosion which impacts greatly on the durability of the building project in the marine or coastal environment has been reported repeatedly. With the problems becoming more and more serious, much attention has been paid on it gradually. To improve the durability of the concrete structure in the marine environment, the author tried to add the different content of steel fiber into the concrete and research the permeability of the concrete in the chloride environment. Four different volumes of steel fiber were selected to prepare the concrete. The dates of the proportion are as follows, 1)0.5%; 2)1%; 3)1.5%; 4)2%. Leave the steel fiber reinforced concrete and plain concrete to soak in the sodium chloride solution which mass percent is 3.5%. The soak time is 30, 60, 90,120, 180 days separately. Among this, the test items include the penetration depth of chloride, the chloride ion content and the splitting strength after soaking period. As a result of the test, it is demonstrated that chloride penetration-resistant of steel fiber reinforced concrete is better than plain concrete. The best performance is obtained when the content of steel fiber is 1.5%. The results will be very useful to the concrete professional dealing with chloride-ion penetration. In conclusion, it is convinced that the application of this result in marine engineering will bring well economic and social environmental benefits for the society.