UBC Theses and Dissertations

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UBC Theses and Dissertations

Development of polypropylene fiber as concrete reinforcing fiber Ratu, Ricky Novry


The objective of this research is to produce polypropylene fibers with improved interface bonding with a concrete matrix. The Laboratory Mixing Extruder paired with the Randcastle fiberline drawing device was used for producing fiber from polypropylene (PP) chips. A target diameter of 0.5 mm fiber was obtained from a 2-stage process in the production line. The effort to improve the fiber surface by applying aluminum oxide sol-gel coating was unsatisfactory due to the failure of the coating materials to adhere to the fiber. Incorporating silica fume (SF) powder in the fiber extrusion process enhanced fiber properties. Silica fume co-extruded PP (SFPP) fiber has different characteristics in appearance, flexibility and surface roughness. Most importantly, the co-extrusions produced significance improvements in surface characteristics. Silica fume particles caused significant changes in the surface roughness of the fiber and contributed to the improved bonding performance in a cement-based matrix. The inclusion of the extruded fibers in a concrete matrix also improved the flexural toughness. Additional testing was conducted to examine the performance of extruded fiber in preventing plastic shrinkage cracking. Fiber reinforced mortar containing RPP and SFPP fibers were evaluated. Based on total crack area reduction efficiency, and crack width reduction efficiency SFPP fibers performed better than RPP fibers. These results indicate that the objective of developing a concrete reinforcing fiber using laboratory equipment was successfully achieved. The inclusion of silica fume particles in the extrusion process significantly changed the properties of the fiber and therefore contributed to the performance of these extruded fibers in the concrete matrix.

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