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Title |
Mechanical Properties of an ECC(Engineered Cementitious Composite) Designed Based on Micromechanical Principle
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Authors |
김윤용 ; 김정수 ; 김희신 ; 하기주 ; 김진근 |
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Keywords |
섬유복합 모르타르 ; 변형률 경화거동 ; 섬유인발실험 ; 쐐기쪼갬시험 ; 마이크로역학 ECC ; strain-hardening behavior ; fiber pullout ; fracture toughness ; micromechanics |
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Abstract |
The objective of this study is to develop a high ductile fiber reinforced mortar, ECC(Engineered Cementitious Composite) with using raw material commercially available in Korea. A single fiber pullout test and a wedge splitting test were employed to measure the bond properties in a matrix and the fracture toughness of mortar matrix respectively, which are used for designing mix proportion suitable for achieving strain-hardening behavior at a composite level. Test results showed that the properties tended to increase with decreasing water-cement ratio. A high ductile fiber reinforced mortar has been developed by employing micromechanics-based design procedure. Micromechanical analysis was initially peformed to properly select water-cement ratio, and then basic mixture proportion range was determined based on workability considerations, including desirable fiber dispersion without segregation. Subsequent direct tensile tests were performed on the composites with W/C's of 47.5% and 60% at 28 days that the fiber reinforced mortar exhibited high ductile uniaxial tension property, represented by a maximum strain capacity of 2.2%, which is around 100 times the strain capacity of normal concrete. Also, compressive tests were performed to examine high ductile fiber reinforced mortar under the compression. The test results showed that the measured value of compressive strength was from 26MPa to 34 MPa which comes under the strength of normal concrete at 28 days.
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