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Simulation of concrete shrinkage taking into account aggregate restraint

  • 발행 : 1997.01.25

초록

This paper proposes a model for simulating concrete shrinkage taking into account aggregate restraint. In the model, concrete is regarded as a two-phase material based on shrinkage property. One is paste phase which undergoes shrinkage. Another is aggregate phase which is much more volumetrically stable. In the concrete, the aggregate phase is considered to restrain the paste shrinkage by particle interaction. Strain compatibility was derived under the assumption that there is no relative macroscopic displacement between both phases. Stresses on both phases were derived based on the shrinking stress of the paste phase and the resisting stress of the aggregate phase. Constitutive relation of paste phase was adopted from the study of Yomeyama, K. et al., and that of the aggregate phase was adopted from the author's particle contact density model. The equation for calculating concrete shrinkage considering aggregate restraint was derived from the equilibrium of the two phases. The concrete shrinkage was found to be affected by the free shrinkage of the paste phase, aggregate content and the stiffness of both phases. The model was then verified to be effective for simulating concrete shrinkage by comparing the predicted results with the autogeneous and drying shrinkage test results on mortar and concrete specimens.

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참고문헌

  1. Deesawangnade, T. (1994), "A model for simulating concrete shrinkage taking into account the effect of aggregate restraint", M. Eng Thesis No. ST-94-29, Asian Institute of Tennology, Bangkok, Thailand
  2. Hobbs, D.W. "Influence of aggregate restraint on the shrinkage of concrete", Journal of ACI, 71(9), 445-450.
  3. Pickett, G. (1956), "Effect of aggregate on shrinkage of concrete and a hypothesis concerning shrinkage", Journal of ACI, 27(5), 581-590.
  4. Shimomura, T. and Maekawa, K. (1993), "Mathematical model for water movement in concrete", Proceedings of the 4th East Asia Pacific Conference on Structural Engineering & Construction, Seoul, Korea, 2, 1425-1430.
  5. Yomeyama, K., Tanzil, G. and Toyama, M. (1993), "Effective tensile Young's modulus of early aged concrete through compressive loading", The 47th Annual Meeting of Japan Cement Association, 380-385 (in Japanese)