혼화재료 및 양생조건에 따른 폴리에틸렌 섬유보강 시멘트 복합재료의 에너지흡수성능 강화

초록

This study aims to enhance the energy absorption capacity of cementitious composites with 2 vol.% of polyethylene fibers, by adjusting mixing ingredients and curing conditions. Ground blast furnace slag, cement kiln dust, limestone powder, and silica fume were incorporated, and two different curing conditions were applied: 72 h of curing at 90 ℃ and 120 h of curing at 40 ℃. Compressive strength test and direct tensile test were performed on 6 mixtures and the test results were compared with those of ultra-high-performance concrete and engineered cementitious composite specimens. The maximum compressive strength of the 6 mixtures was measured to be approximately 117 MPa. The higher cement replacement ratio of the other components resulted in a decrease in the compressive strength of the specimens cured at 90 ℃. In the direct tensile test, the specimens cured at 40 ℃ exhibited lower tensile strength than those cured at 90 ℃, but the strain capacity was increased by approximately 305% and reached 7.7%. This also resulted in an enhancement of the energy absorption capacity from 80%–292% because of the differences in micro-cracking and fracturing behaviors, such as an increase inthe number of micro-cracks and decrease in crack width.

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