Computers and Concrete

  • 제8권4호
  • /
  • Pages.425-443
  • /
  • 2011
  • /
  • 1598-8198(pISSN)
  • /
  • 1598-818X(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Thermal stress and pore pressure development in microwave heated concrete

  • Akbarnezhad, A. (Department of Civil Engineering, National University of Singapore) ;
  • Ong, K.C.G. (Department of Civil Engineering, National University of Singapore)
  • 투고 : 2010.01.11
  • 심사 : 2010.08.11
  • 발행 : 2011.08.25
⟨ 이전 논문 다음 논문 ⟩

초록

Most previous studies have generally overlooked the contribution of thermal stresses generated within the concrete mass when subjected to microwave heating and reported on pore-pressure as being the dominant cause of surface spalling. Also, the variation in electromagnetic properties of concrete and its effects on the microwave heating process have not been studied in detail. In this paper, finite element modeling is used to examine the simultaneous development of compressive thermal stresses and pore-pressure arising from the microwave heating of concrete. A modified Lambert's Law formulation is proposed to estimate the microwave power dissipation in the concrete mass. Moreover, the effects of frequency and concrete water content on the concrete heating rate and pattern are investigated. Results show high compressive stresses being generated especially in concrete with a high water content when heated by microwaves of higher frequencies. The results also reveal that the water content of concrete plays a crucial role in the microwave heating process.

키워드

참고문헌

  1. Akbarnezhad, A., Ong, K.C.G., Zhang, M.H., Tam, C.T. and Foo, T.W.J. (2011), "Microwave-assisted beneficiation of recycled concrete aggregates", Constr. Build. Mater., 25, 3469-3479. https://doi.org/10.1016/j.conbuildmat.2011.03.038
  2. Ayappa, K.G., Davis, H.T., Crapiste, G., Davis, E.A. and Gordon, J. (1991), "Microwave heating: an evaluation of power formulations", Chem. Eng. Sci., 64(4), 1005-1016.
  3. Ayers, K.W. (1998), Feasibility of recycling contaminated concrete, Environmental Engineering, Vanderbilt University, Nashville, Tennessee, United States.
  4. Barringer, S.A., Davis, E.A., Gordon, J., Ayappa, K.G. and Davis, H.T. (1995), "Microwave heating temperature profiles for thin slabs compared to Maxwell and Lambert's law predictions", J. Food Sci., 60(5), 1137-1142. https://doi.org/10.1111/j.1365-2621.1995.tb06309.x
  5. Bazant, Z.P. and Goangseup, Zi. (2003), "Decontamination of radionuclides from concrete by microwave heating. I: Theory", J. Eng Mech., 129(7),777-784. https://doi.org/10.1061/(ASCE)0733-9399(2003)129:7(777)
  6. Bazant, Z.P. and Kaplan, M.F. (1996), Concrete at high temperatures: material properties and mathematical models, Harlow, Essex: Longman Group.
  7. Bazant, Z.P. and Thonguthai, W. (1978), "Pore pressure and drying of concrete at high temperature", J. Eng. Mech. Div. - ASCE, 104(5), 1059-1079.
  8. Lagos, L.E., Li, W. and Ebadian, M.A. (1995), "Heat transfer within a concrete slab with a finite microwave heating source", Int. J. Heat Mass Tran., 38(5), 887-897. https://doi.org/10.1016/0017-9310(94)00200-F
  9. Li, W. and Ebadian, M.A. (1994), "Heat and mass transfer in a contaminated porous concrete slab with variable dielectric properties", Int. J. Heat Mass Tran., 37(6), 1013-1027. https://doi.org/10.1016/0017-9310(94)90226-7
  10. Li, W., Ebadian, M.A., White, T.L. and Grubb, R.G. (1993), "Heat transfer within a concrete slab applying the microwave decontamination process", J. Heat Transfer, 115(1), 42-50. https://doi.org/10.1115/1.2910667
  11. Nykvist, W.E. and Decareau, R.V. (1976), "Microwave meat roasting", J. Microwave Power, 11(1), 3-24.
  12. Ohlsson, T. and Bengtsson, N. (1971), "Microwave heating profiles in foods-a comparison between heating experiments and computer simulation", Microw. Energy Appl. Newsl., 4(6), 3-8.
  13. Pozar, D.M. (1998), Microwave engineering, John Wiley & Sons.
  14. Rei, R.C., Prauznitz, J.M. and Poling, R.E. (1987), The properties of gases and liquids, 4th Ed., McGraw Hill, New York.
  15. Rhim, H.C. and Buyukozturk, O. (1998), "Electromagnetic properties of concrete at microwave frequency range", J. ACI Mater., 95(3), 262-271.
  16. Saltiel, G. and Datta, A.K. (1999), "Heat and mass transfer in microwave processing", Adv. Heat Trans., 33(1), 91-94.
  17. Spalding, B. (2000), "Volatility and extractability of Strontium-85, Cesium-134, Cobalt-57, and Uranium after heating hardened portland cement paste", Env. Sci. Tech., 34(23), 5051-5058. https://doi.org/10.1021/es001396h
  18. Taoukis, P., Davis, E.A., Davis, H.T., Gordon, J. and Talmon, Y. (1987), "Mathematical modeling of microwave thawing by the modified isotherm migration method", J. Food Sci., 52(2), 455-463. https://doi.org/10.1111/j.1365-2621.1987.tb06638.x
  19. Watson, A. (1968), Breaking of concrete, Microwave power engineering, E.C. Okress, ed, Vol. 2, Academic, New York.
  20. White, T.L., Foster, D. Jr., Wilson, C.T. and Schaich, C.R. (1995), Phase II: microwave concrete decontamination results, ORNL Rep. No. DE-AC05-84OR21400., Oak Ridge National Laboratory, Oak Ridge, Tenn.
  21. White, T.L., Grubb, R.G., Pugh L.P., Foster, D. Jr. and Box, W.D. (1992), "Removal of contaminated concrete surface by microwave heating - Phase 1 results", Proceedings of 18th American Nuclear Society Symposium on Waste Management, Tucson, AZ., American Nuclear Society, La Grange Park, Illinois, 745-748.
  22. Zi, Goangseup and Bazant, Z.P. (2003), "Decontamination of radionuclides from concrete by microwave heating. II: Computations", J. Eng Mech., 129(7), 785-792. https://doi.org/10.1061/(ASCE)0733-9399(2003)129:7(785)

피인용 문헌

  1. A pilot study on microwave heating for production and recycling of road pavement materials vol.44, 2013, https://doi.org/10.1016/j.conbuildmat.2013.02.082
  2. Sustainable Construction for Singapore's Urban Infrastructure – Some Research Findings vol.171, 2017, https://doi.org/10.1016/j.proeng.2017.01.305
  3. The Bearing Capacity of Reinforced Concrete Member Under Different Temperatures vol.21, pp.3, 2011, https://doi.org/10.2190/AF.21.3.d
  4. Theoretical and experimental analysis of wave propagation in concrete blocks subjected to impact load considering the effect of nanoparticles vol.20, pp.6, 2011, https://doi.org/10.12989/cac.2017.20.6.711