| Summary: | 博士 === 國立臺灣海洋大學 === 河海工程學系 === 102 === Polyolefin fibers are a new commercial synthetic product, allowing high volume production of composites without fiber balling. Inclusion of polyolefin fibers in concrete was useful to improve the mechanical properties, such as tensile strength, impact strength, and abrasion resistance. However, many previous researchers have studied either polyolefin fibers or ggbs individually; few studies have evaluated the combination of polyolefin fibers and ggbs mixed into cement-based composites. This study evaluated the mechanical properties, permeability and porestructures of concrete produced with added polyolefin fibers and ggbs. Material variables included the dosage of ggbs and dosage of polyolefin fiber.
Researchers conducted tests on compressive strength, splitting tensile strength, modulus of elasticity, resistivity, rapid chloride penetration, water absorption, performed porestructure and microscopic observation. Test results indicate that the specimens containing ggbs have higher compressive strength, lower absorption, lower resistivity, lower total charge-passed, denser porestructures than the control and specimen made with fibers. The specimens with polyolefin fiber and ggbs have considerably higher tensile strength than the control and specimens made with ggbs.
The specimens containing ggbs and polyolefin fiber demonstrated better resistance to chloride penetration than concrete with polyolefin fiber or silica fume. Specimens containing ggbs demonstrated a significant increase in resistivity and decrease in the total charge passed and absorption. Scanning electron microscopy illustrates that the polyolefin fiber acts to arrest the propagation of internal cracks but there are cracks and weakness between fiber and paste caused harmful ions penetrated easier.
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