부산대학교 도서관

In the past few decades, small fibers are increasingly used in reinforcement of concrete as an enhancement or alternative to steel bars. The addition of plastic fibers in the concrete matrix improves performance, reduces material costs and provides better working conditions on site such as reduction in concrete mixing noise in residential areas. Fibers attenuate the formation of cracks in concrete and enhance the structural behavior with increased shear, ductility, flexural capacity as well as compressive strength. This paper examines the effects of incorporation of macro synthetic fibers on the properties of fresh concrete and structural behavior in hardened state. For this purpose, polypropylene fibers were added at a dosage of 0.25%, to 1% to the concrete mix. To assess the performance of polypropylene (PP) fiber reinforced concrete, the samples were compared with identical plain concrete members. From the experimental investigations, it was noted that the workability of concrete with a constant mix design was adversely affected by the increase in fiber content. The slump tests with fresh concrete showed a slump of 50mm for plain concrete and decreased to zero slump for the same mix proportions with the addition of 1% of polypropylene fibers. The effects of fiber volume and type on hardened concrete were evaluated using standard strength tests. There was no significant effect on the compressive strength. However, at low fiber content of 0.5%, the results exhibited an increase in compressive strength. The flexural performance of small concrete beams showed improvement with the addition of low volume of plastic fibers. With the addition of fibers, there is a change in the pattern of failure, wherein even upon reaching the ultimate load the beams failed in a pseudo-ductile manner. This was attributed to the concrete crack bridging properties of the fibers. On the basis of the experiments and data analysis, the results have clearly showed enhancement in the structural and mechanical behavior of concrete reinforced with plastic fibers as compared to plain concrete. [ABSTRACT FROM AUTHOR]