Study on Resistance of Chloride Ion Penetration in Fly Ash / Silicon Ash Polypropylene Fiber Concrete under Preloading Condition

Abstract

Through NEL experimental method and scanning electron microscopy test (SEM), the resistance of chloride ion penetration in the concrete admixed with polypropylene fiber, complex minerals (fly ash/silicon ash with weight ratio of 4∶1), and polypropylene fiber under axial compressive loading or not was studied. The results show that, under no-load condition, the compactness between aggregate and cement stone improves, and the number and the width of the crevice obviously decrease in concrete specimens admixed with appropriate amount of polypropylene fiber and complex minerals. From the view of macro property, the diffusion coefficients of chloride ion decrease, and the anti-chloride ion permeability obviously increases when compared with that of the concrete admixed with polypropylene fiber or multiple minerals. The optimal proportion of the concrete for anti-chloride ion permeability is the composition of 0．1% polypropylene fiber and 25 % complex minerals co-doped. The diffusion coefficients of chloride ion slightly decrease firstly and then increase in concrete under axial compressive load. Under the same stress ratio, the chloride ion diffusion coefficient is the minimum for concrete with polypropylene fiber and complex minerals co-doped.

Keywords: fly ash,  polypropylene fibers,  axial compressive load,  resistance of chloride ion penetration