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Genetic algorithm-based yield stress equations for concrete at high temperature and prolonged mixing time

  • Martini, S. Al (Department of Civil and Environmental Engineering, The University of Western Ontario) ;
  • Nehdi, M. (Department of Civil and Environmental Engineering, The University of Western Ontario)
  • 투고 : 2008.07.21
  • 심사 : 2009.07.08
  • 발행 : 2009.08.25

초록

Experiments were designed to investigate the flow behavior of portland cement paste and concrete incorporating superplasticizers. The paste and concrete mixtures were subjected to prolonged mixing for up to 110 min at high temperature. The yield stress values of concrete and that of the corresponding cement paste were measured using a rotating rheometer and viscometer, respectively. The results reveal a weak linear correlation between the yield stress of concrete mixtures and that of the corresponding cement pastes. Results also indicate that the yield stress of concrete varies in a linear fashion with the elapsed time, while its variations with the temperature and superplasticizer dosage follow power and inverse power functions, respectively. In this study, the genetic algorithms (GA) technique was used to predict the yield stress of concrete considering various parameters, such as the mixing time, ambient temperature, and superplasticizer dosage. A sensitivity study was conducted to evaluate the ability of the GA equations thus developed to capture the effects of test parameters on the yield stress of concrete. It was found that the GA equations were sensitive to the effects of test parameters and provided yield stress predictions that compared well with corresponding experimental data.

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참고문헌

  1. Al-Martini, S. and Nehdi, M. (2009-a), "Coupled effects of time and high temperature on rheological properties of cement pastes incorporating various chemical admixtures", J. Mater. Civil Eng., ASCE, 21(8), 1-11. https://doi.org/10.1061/(ASCE)0899-1561(2009)21:1(1)
  2. Al-Martini, S. and Nehdi, M. (2009-b), "Genetic Algorithm Rheological Equations for Cement Paste", Proc. ICE. Constr. Mater.
  3. Asaga, K. and Roy, D. M. (1980), "Rheological properties of cement mixes: effects of superplasticizers on viscosity and yield stress", Cement Concrete Res., 10(2), 287-295. https://doi.org/10.1016/0008-8846(80)90085-X
  4. Ferraris, C. and de Larrad, F. (1998), "Testing and modeling of fresh concrete rheology," NISTIR 6094, National Institute of Standards and Technology, 1-61.
  5. Geiker, M.R., Brandl. M., Thrane, L.N., Bager, D.H. and Wallevik, O. (2002), "The effect of measuring procedure on the apparent rheological properties of self-compacting concrete," Cement Concrete Res., 32(2), 1791-1795. https://doi.org/10.1016/S0008-8846(02)00869-4
  6. Maruya, E., Osaki, M. and Igarashi, H. (2006), "Relationships between rheological constant of cement paste and fluidity of high-fluidity concrete", J. Adv. Concrete Tech., 4(2), 251-257. https://doi.org/10.3151/jact.4.251
  7. Michalewicz, Z. (1996), Genetic algorithm + data structures = evolution programs, Springer-Verlag, New-York, 13-45.
  8. Murarta, J. and Kikukawa, H. (1992), "Viscosity Equation for Fresh Concrete", ACI Mater. J., 89(3), 230-237.
  9. Nehdi, M. and Al-Martini, S. (2009), "Coupled effects of high temperature, prolonged mixing time, and chemical admixtures on rheology of fresh concrete", ACI Mater. J., 106(3), 1-10.
  10. Petit, J.Y., Wirquin, E., Vanhove, Y. and Khayat, K. (2007), "Yield stress and viscosity equations for mortars and self-consolidating concrete", Cement Concrete Res., 37(5), 655-670. https://doi.org/10.1016/j.cemconres.2007.02.009
  11. Saak, A.W., Jennings, H.M. and Shah, S.P. (2004), "A generalized approach for the determination of yield stress by slump and slump flow", Cement Concrete Res., 34(3), 363-371. https://doi.org/10.1016/j.cemconres.2003.08.005
  12. Struble, L.J. and Chen, C.T. (2005), "Effect of continuous agitation on concrete rheology", J. ASTM Int., 2(9), 1-19. https://doi.org/10.1520/JAI12938
  13. Tattersall, G.H. (1991), Workability and quality control of concrete, E & FN Spon, London, 37-45.
  14. Wallevik, J.E. (2006), "Relationship between the bingham parameters and slump", Cement Concrete Res., 36(7), 1214-1221. https://doi.org/10.1016/j.cemconres.2006.03.001
  15. Yahia, A. and Khayat, K.H. (2001), "Analytical models for estimating yield stress of high-performance pseudoplastic grout", Cement Concrete Res., 31(5), 731-738. https://doi.org/10.1016/S0008-8846(01)00476-8