Study On Polyester Fiber Durability Desert Sand Of Concrete

Since it has advantages like high intensity, acid-proof alkali, low-price etc, polyester fiber has been widely used in the textile industry of our country, but it also has been to be refractory and unmanageable. Using desert sand instead of engineering medium sand can reduce the economical lost greatly during the exploring and long distance transportation of common medium sand, however, desert sand has disadvantages of large specific surface area and causticity. Considering to use polyester waste as the reinforcement material of concrete can not only ease the pollution problems raised by polyester fiber, since it’s hard for natural degradation, but also create much more economic benefits and social benefits as polyester fiber can overcome its causticity of desert sand.Based on previous studies on this topic, taken green, environmental protection and cost saving as the principle, we chose polyester fiber abandoned by polyester fiber factories and the Mu Us desert sand of Ningxia local as modified materials of concrete. The optimal set, the concrete prepared with the optimal mix ratio and the benchmark set, common concrete were compared through orthogonal tests, and the mechanical properties testing of compressive strength, splitting tensile strength, frost resistance and impermeability have been done, the results show that:(1) the following of the effect to Mu Us desert sand concrete28d compressive strength is:the mixing amount of polyester fiber> the length of polyester fiber> the replacement rate of desert sand, among which the mixing amount of polyester fiber has the biggest impact and the replacement rate of desert sand the least.(2) the following of the effect to Mu Us desert sand concrete slump is:the replacement rate of desert sand> the mixing amount of polyester fiber> the length of polyester fiber, the impact of the first two factors is very obvious.(3) it’s possible that using Mu Us desert sand as fine aggregate to compound concrete, and the optimal mix ratio of the relatively common concrete C35when compounding is that the replacement rate of desert sand is30%, the length of polyester fiber is35mm and the mixing amount of polyester fiber is1.0kg/m2, it’s the optimal set.(4) in terms of the research on the frost resistance of polyester fiber desert sand, the mass of benchmark set lost up to0.5%and relative dynamic modulus decreased to73.1%after75times freeze thaw cycling, while the mass of the optimal set lost only0.3%and relative dynamic modulus of it decreased to93.2%. When the freeze thaw cycling came to100times, the relative dynamic modulus of the optimal set was still above90%and the mass loss was0.3%as usual. Until the freeze thaw cycling was up to150times, our experiment was stopped because the mass loss of the optimal set came to0.5%, at the same time, the relative dynamic modulus was80.5%. According to the data above, we can found that the cracking-resistance and frost heave resistance of the optimal set is better than that of the benchmark set.(5) in terms of the research on the impermeability of polyester fiber desert sand concrete, the seepage height of the optimal set was27.9mm while that of the benchmark set was39.5mm when the water pressure was added to1,2Mpa, since then, the impermeability of polyester fiber desert sand concrete is better than that of the benchmark, thus polyester fiber can block the developing of concrete crack, and diminish the pore opening of concrete.