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http://dx.doi.org/10.4334/JKCI.2003.15.2.305

Experimental Study on Coefficient of Air Convection  

Jeon, Sang-Eun (Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology)
Kim, Jin-Keun (Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology)
Publication Information
Journal of the Korea Concrete Institute / v.15, no.2, 2003 , pp. 305-313 More about this Journal
Abstract
The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the coefficient of air convection, which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind and types of form. From experimental results, the coefficient of air convection was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent coefficient of air convection including effects of velocity of wind and types of form was theoretically proposed. The coefficient of air convection in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with types of form. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the coefficient of air convection by this model was well agreed with those by experimental results.
Keywords
thermal property; coefficient of air convection; velocity of wind; type of form;
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  • Reference
1 四國電力(株),'マスコンクリ-トの初期ひび割れとその 防止對策に關する硏究', 1964
2 山川, 笠原, 小林, 'マスコンクリ-トの熱傳道率試驗方法 の檢討', 弟37回土木學會年次學術譯潛參漑要集, 弗5部, 1982
3 小澤睪三, 'マスコンクリ-トの初期ひび劃れとその防止 對策に關する硏究(I)', 發電水力, No. 57, 1962
4 김국한, 전상은, 방기성, 김진근, '콘크리트의 열전도율에 관한 실험적 연구', 한국콘크리트학회논문집, Vol. 13, No. 4, 2001, pp305-313
5 이택식, 이재현, 이준식, '열전달', 희중당, 1992
6 Fermando, A B., Mendes, P. A, and Mirambell, E, 'Heat of Hydration Effects in Concrete Structures', ACI Materials Journal, 1992, pp.139
7 Mendes, P. A, 'Temperature Gradients for Concrete Bridges,' MSc thesis, Technical University of Lisbon, 1989
8 Chapman, 'Fundamental of Heat Transfer,' Macmillian Inc., New York, 1982
9 Rastrup, E, 'Heat of Hydration in Concrete,' Magazine of Concrete Research, Vol. 6, No. 17, 1954, pp.79-92   DOI
10 Hsieh, C, Qin, C., and Ryder, E., 'Deuelopment of Computer Modelling for Prediction of Temperature Distribution Inside Concrete Pavements,' Report FL/D0T/S0/90 374, Mechanical Engineering Dept, University of Florida, Gainesville, 1989