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Title |
Evaluation on Rear Fracture Reduction and Crack Properties of Cement Composites with High-Velocity Projectile Impact by Fiber Types
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Authors |
한상휴(Sang-Hyu Han) ; 김규용(Gyu-Yong Kim) ; 김홍섭(Hong-Seop Kim) ; 김정현(Jung-Hyun Kim) ; 남정수(Jeong-Soo Nam) |
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DOI |
http://dx.doi.org/10.4334/JKCI.2015.27.2.157 |
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Keywords |
시멘트 복합체 ; 섬유보강 ; 휨인성 ; 배면박리 ; 섬유개체수 ; 미세균열 cement composites ; fiber reinforced ; flexural toughness ; scabbing ; number of fibers ; micro-crack |
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Abstract |
Cement composites subjected to high-velocity projectile shows local failure and it can be suppressed by improvement of flexural toughness with reinforcement of fiber. Therefore, researches on impact resistance performance of cement composites are in progress and a number of types of fiber reinforcement are being developed. Since bonding properties of fiber with matrix, specific surface area and numbers of fiber are different by fiber reinforcement type, mechanical properties of fiber reinforced cement composites and improvement of impact resistance performance need to be considered. In this study, improvement of flexural toughness and failure reduction effect by impact of high-velocity projectile have been evaluated according to fiber type by mixing steel fiber, polyamide, nylon and polyethylene which are have different shape and mechanical properties. As results, flexural toughness was improved by redistribution of stress and crack prevention with bridge effect of reinforced fibers, and scabbing by high-velocity impact was suppressed. Since it is possible to decrease scabbing limit thickness from impact energy, thickness can be thinner when it is applied to protection. Scabbing of steel fiber reinforced cement composites was occurred and it was observed that desquamation of partial fragment was suppressed by adhesion between fiber and matrix. Scabbing by high-velocity impact of synthetic fiber reinforced cement composites was decreased by microcrack, impact wave neutralization and energy dispersion with a large number of fibers.
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