Effect of Polyolefin Fibers and Supplementary Cementitious Materials on Corrosion Behavior of Cement-Based Composites

摘要

The present study evaluated the corrosion behavior of cement-based composites containing polyolefin fibers and supplementary cementitious materials by the impressed voltage corrosion test and the impressed current corrosion test. Material variables included the addition of polyolefin fiber (0, 0.4, 0.8 and 1.6 %), the dosage of ultrafine slag (40 and 60 %), the dosage of fumed silica (2 and 5 %) and mixed cementitious materials (35 % slag plus 5 % fumed silica and 55 % slag plus 5 % fumed silica). The test results indicate that a small amount of polyolefin fibers extends the time that a chlorine ion reaches to the surface of the rebar and decreases the corrosion rate of rebar. Nevertheless, the fiber is not very useful for the corrosion resistance of steel when the chlorine ions reach the surface of the rebar and corrode it. In addition, the inclusion of ultrafine slag or fumed silica can arrest the rebar corrosion and improve the compactness through pozzolanic reactivity and pore filling effects. According to the corrosion behavior and economy performance of the concrete structure, the combination of 55 % ultrafine slag, 5 % fumed silica and 0.8 % polyolefin fibers provides the best corrosion resistance of the tested cement-based composites.