Use of Recycled Plastic Waste Fiber to Improve the Tensile Strength of Concrete

Abstract

This research aims to study the effect of recycled plastic fibers as fiber reinforcement in concrete. The recycled plastic fibers were made from polypropylene type (PP), with a diameter of 1 mm and length of 30 and 60 mm, used at rates of 0.5 and 1.0% by weight of cement. The mechanical properties in terms of compressive strength were tested at 7, 14 and 28 days. The splitting tensile strength was also investigated at 7 and 28 days to compare the mechanical properties of concrete mixed with recycled plastic fibers and normal concrete without fiber reinforcement. The test result found that the use of recycled plastic fibers at 0.5% by weight of cement had slightly higher compressive strength than that of 1% by weight, for both fiber length of 30 mm and 60 mm. For the tensile strength of concrete, it was indicated that using recycled plastic fibers at a length of 60 mm enhanced splitting tensile strength better than at 30 mm at 0.5% by weight, while the splitting tensile strength of concrete using recycled plastic fibers at a length of 30 mm was better than at 60 mm at 1% by weight. The result clearly showed that the ratio of splitting tensile strength to compressive strength of recycled plastic fiber concrete was higher than that of conventional concrete. Recycled plastic fiber concrete had a ratio of tensile strength to compressive strength of 14.2 to 15.5, while conventional concrete had a ratio of tensile strength to compressive strength of 11.2 to 11.5.