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등가재령 방법에 의한 혼화재 치환 고강도 시멘트 모르타르의 자기수축 해석에 관한 연구

A Study on the Estimation of Autogenous Shrinkage of High Strength Mortar incorporating Mineral Admixture by Equivalent Age Method

  • Han, Min-Cheol (Department of Architectural Engineering, Cheong-Ju University)
  • 투고 : 2013.12.24
  • 심사 : 2014.01.21
  • 발행 : 2014.02.20

초록

본 연구에서는 양생온도변화에 따른 자기수축의 예측을 위하여 FA 및 SF를 치환한 시멘트모르타르를 대상으로 자기수축변화를 측정하고 이를 등가재령방법으로 해석하고자 하였다. 이를 위해 수화반응의 온도민감도를 고려하는 Ea의 변화에 따라 지수함수모델을 이용하여 자기수축 해석을 실시하였는데, 경화단계의 $E_a$를 이용할 경우 응결단계의 $E_a$를 사용한 경우보다 정확한 해석이 가능한 것으로 나타났는데, 이는 경화의 전단계에 걸친 수화의 온도민감도 영향을 반영한 $E_a$값에 기인된 결과로 사료된다.

The objective of this study is to investigate an effect of curing temperature on autogenous shrinkage of high strength cement mortar with 0.15 of W/B incorporating fly ash and silica fume in terms of equivalent age. The contents of fly ash and silica fume are varied from 10% to 30%. Non linear regression model applying equivalent age was used to estimate the autogenous shrinkage evolution. To obtain apparent activation energy($E_a$), setting time method by Pinto and existing method were calculated and compared respectively. Test results showed that use of silica fume increased autogenous shrinkage while use of fly ash decreased it. It was also found that poor agreements were obtained when $E_a$ by setting time was applied. But, application of existing $E_a$ resulted in a good agreement between calculated autogenous shrinkage and measured one.

키워드

참고문헌

  1. Aiticin PC. Autogenous shrinkage measurement. Proceeding of International Workshop on Autogenous Shrinkage of Concrete. In: Eichi Tazawa, editor, 1998 Sept; Hiroshima (Japan). Newyork (NY(): E&FN Spon; c1999. p. 257-67.
  2. Tazawa E, Miyazawa S, Kasai T. Chemical shrinkage and autogenous Shrinkage of hydrating cement paste. Cement and Concrete Research. 1995 Feb;25(2):288-92. https://doi.org/10.1016/0008-8846(95)00011-9
  3. Turcry P, Loukili A, Barcelo L, Casabonne JM. Can maturity concept be used to separate the autogenous shrinkage and thermal deformation of a cement paste at early age. Cement and Concrete Research. 2002 Nov;32:1443-50. https://doi.org/10.1016/S0008-8846(02)00800-1
  4. Tazawa E, Matuoka Y, Miyazawa S, Okamoto S. Effect of autogenous shrinkage on self stress in hardening concrete. International Symposium on Thermal Cracking in Concrete at Early Ages; 1994 Nov; Munchen (Germany). London (UK): E&FN Spon; 1994. p. 221-28.
  5. Loukli A, Chopin D, Kheldj A, Touzo J. A New approach to determine autogenous shrinkage of mortar at an early age considering temperature history. Cement and Concrete Research. 2000 Jul;30(7):915-22. https://doi.org/10.1016/S0008-8846(00)00241-6
  6. Chu IP, Kwon SH, Amin MN, Kim JK. Estimation of temperature effects on autogenous shrinkage of concrete by a new prediction model. Construction and Building Materials. 2012 Oct;35(10):171-82. https://doi.org/10.1016/j.conbuildmat.2012.03.005
  7. Holt E. Contribution of mixture design to chemical and autogenous shrinkage of concrete at early ages. Cement and concrete research. 2005 Mar;35(3):464-72. https://doi.org/10.1016/j.cemconres.2004.05.009
  8. Zhang MH, Tam CT, Leow MP. Effect of water to cementitious materials ratio and silica fume on autogenous shrinkage of concrete. Cement and Concrete Research. 2003 Apr;33(3):1687-94. https://doi.org/10.1016/S0008-8846(03)00149-2
  9. Jensen OM, Hansen P. Influence of temperature on autogenous shrinkage deformation and relative humidity change in hardening cement paste. Cement and Concrete Research. 1999 Mar;29(4):567-75. https://doi.org/10.1016/S0008-8846(99)00021-6