Study On The Salt Frost Resistance Of Polypropylene Fiber Concrete

The concrete salt scaling destruction is one of the most primary causes of our concrete structure aging and disease, for seasonal change, the concrete under water erosion,salt frozen functions in the splash area, Salt scaling circulation will lead to the surface erosion of the concrete,the damage of concrete and the bearing capacity of concrete will be decline, it is influenced the durability of concrete structure. Adding polypropylene fiber is an effective way to increase the resistant of cracking of concrete, with the economy and technology development in our country, the polypropylene fiber concrete applied to engineering practice more and more. Therefore, it is important for us to study the salt resistant of polypropylene fiber concrete. To simulate the Marine splash region of the durability of concrete with salt frozen influence, this paper made the following work:This paper conducted the research which polypropylene fiber concrete action in salt scaling circulation. By the polypropylene fiber dosage and freeze-thaw cycle time, analysis salt frozen circulation factors of concrete quality loss, modulus loss, flexural strength and splitting tensile strength of variation ; And use the SEM scanning methods, observe the change of the microstructure, analysis the polypropylene fiber dosage impact on microstructure of concrete Basis on the macroscopic mechanics damage, use the experiment date, establish the equation of the polypropylene fiber concrete action in salt scaling cycle, discusses the development of frozen cycling time macroscopic damage evolution. The test results show that the polypropylene fiber restrain the concrete peel off, with the fiber contents increase, the quality of concrete,relative loss modulus,relative folding strength and splitting tensile strength of concrete decrease rate have been slowed, the concrete freezing salt resistant performance improved. This paper conducted the research which polypropylene fiber concrete action in salt scaling circulation before dry-wet cycle, with the fiber dosage and dry- wet cycle time as the main investigation factors, analyze the quality loss,loss modulus and the flexural strength of concrete compared with the salt frozen test. The results show that with the dry-wet recycle number increase, the declining rate of quality of concrete loss,relative loss modulus and relative folding strength are slowed, but the performance is not significant.