| Summary: | 碩士 === 國立嘉義大學 === 土木與水資源工程學系研究所 === 99 === Polypropylene (PP) fiber is usually to enhance the physical and mechanical properties of concrete. However, the hydrophobic surface properties of polypropylene fibers induce the low adhesion force between cement matrix and these fibers. In this study, potassium dichromate (K2Cr2O7) and potassium permanganate (KMnO4) solutions were used to treat PP fiber. The treated PP fiber was applied in preparing mortars understand the improvement of hysical, mechanical and other properties of mortar.
The experimental results showed that, the compressive, flexural , tensile strength and pull strengths of the mortar specimen with treated PP fiber, were improved. For the specimen with K2Cr2O7 treated PP, the compressive strength increased from 1.4% to 8.3%, flexural strength increased by 2.4% to 8.0%, the tensile strength increased from 1.4% to 5.5%, and the pull strength increased from 9.1%~ 31.1%. KMnO4 treated PP enhanced mortar’s, compressive strength from 0.3% to 7.6%, flexural strength from 0.8% to 4.9%, the tensile strength about 0.0% to1.9%, and the pull strength from 4.6% to 17.3%.
OM and SEM pictures showed that K2Cr2O7 and KMnO4 treatment enhanced the adhesion between PP and cement hydrate. FT-IR spectrum depicted the production of some functions. K2Cr2O7 treatment induced the production of f C = C bond; and KMnO4 treatment gave the production of C = O bond, AFM images showed that PP film treated with K2Cr2O7 made the average roughness increased from 49.7nm to 303.6nm; and KMnO4 treatment increased the average surface roughness from 49.7nm to 374.3nm.
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