Impermeability Durability of SCC Reinforced with Fibrillated Polypropylene Fiber

The paper has studied the influences of the volume content and slenderness ratio of fibrillated polypropylene fiber on the impermeability durability of self-consolidating concrete (SCC) reinforced with the fibrillated polypropylene fiber, and proposed to use the modified relative permeability coefficient method to evaluate the water-resistant properties of SCC reinforced with the fiber. Also, the influence mechanism of the fiber on the permeability of the concrete has been analyzed according to the mercury injection test, scanning electronic microscope (SEM) observation and the basic principles of fracture mechanics. Results show that: 1) the total porosity of SCC gradually increases with the increase of the fiber content; 2) the harmful porosity of SCC decreases firstly and then increases with the increase of the fiber content, while the harmful porosity increases with the increase of the fiber length; 3) when the reference mix proportion of SCC is constant, the fiber volume content is not more than 0.10 %, and the appropriate fiber length ranges from 12 to 15mm; 4) when the volume content is no more than 0.15%, the hardened SCC reinforced with fibrillated polypropylene fiber possesses good water impermeability gradation (>P12); the splitting strength and flexural tensile strength of the hardened SCC reinforced with fibrillated polypropylene fiber increase with the addition of the fiber content; the relative water penetration coefficient of the hardened SCC reinforced with fibrillated polypropylene fiber decreases with the addition of the fiber content firstly and then increase; the Coulomb value first increases smoothly (the maximum Coulomb value is less than 2000C, and low according to JTJ/T 193-2009 and ASTM C 1202), then increases sharply.