http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
문주현(Mun, Ju-Hyun),문재성(Mun, Jae-Sung),양근혁(Yang, Keun-Hyeok) 대한건축학회 2013 大韓建築學會論文集 : 構造系 Vol.29 No.8
To evaluate the stress-strain relationship of heavyweight concrete (HWC) and formulate a reasonable model, 26 mixes were prepared under various parameters including water-to-binder ratio, replacement level with natural aggregate for magnetite aggregates, and the replacement level of fly ash. Based on the current test results and existing data, modulus of elasticity, and strains at the peak stress and at 50% of peak stress in the descending branch were formulated as a function of compressive strength and unit weight of concrete. The factor to determine the slopes of ascending and descending branches of the stress-strain curve was solved by numerical analysis and formulated through the parametric study. Test results demonstrated that the stress-strain behavior of concrete is significantly affected by its unit weight as well as its compressive strength. ACI 349-06 provision unconservatively predicts the modulus of elasticity of HWC, and CEB-FIP and EC2 provisions overestimate the strain at peak stress. Meanwhile, the proposed models are in good agreement with test results, giving a consistency with the trends observed in tests.
섬유 및 혼화제를 이용한 황토 모르타르의 수축균열 제어
문주현(Mun Ju-Hyun),양근혁(Yang Keun-Hyeok),전중규(Jeon Joong-Kyu),황혜주(Hwang Hye-Zoo) 대한건축학회 2012 大韓建築學會論文集 : 構造系 Vol.28 No.8
A total of 8 hwang-toh mortar mixes with no cement were tested to evaluate the effect of different fibers and admixtures on the control of shrinkage cracks of such mortars. The fiber types added were Lyocell, Poly-Amid and PVA, while, CSA and organic polymer were selected as the admixture. The shrinkage crack resistance of hwang-toh mortar were examined from the unrestrained drying shrinkage strain, restrained drying shrinkage and plastic shrinkage. Test results revealed that the unrestrained drying shrinkage strain of hwang-toh mortar sharply increased at an early age showing approximately 2.5 times higher values than predictions obtained from ACI 209, regardless of the addition of fibers and admixtures. In addition, cracks owing to the restrained drying shrinkage developed at the only age of 1.6 days in all test mixes; as a result, the cracking grade of hwang-toh mortar was evaluated to be high. On the other hand, the addition of fibers required a value of fiber spacing above 0.0003 in order to enhance the tensile resistance capacity of hwang-toh mortar under the restrained drying shrinkage and reduce the cracking area under the plastic shrinkage. Overall, it could be concluded that moist curing at an early age and the addition of fiber with fiber spacing above 0.0003 are practically effective in reducing shrinkage crack of hwang-toh mortar.