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Dielectric Permittivity of Various Cement-Based Materials during the First 24 Hours Hydration

DOI: 10.4236/ojinm.2013.34009, PP. 53-57

Keywords: Dielectric Permittivity, Cementitious Materials, Hydration, Microwave Energy

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Abstract:

The dielectric permittivity of cementitious materials during 24 hours hydration period at a frequency of 2.45 GHz using a network analyzer with open-ended probe technique was measured. Influences of water-to-cementitious ratios, cement types, pozzolans and aggregate types are taken into consideration. The results show that dielectric permittivity is strongly affected by initial water-to-cementitious ratio and the rate of hydration reaction which can be changed by fineness of cement (Types 1 and 3), pozzolan materials and aggregates (river sand with/without crushed limestone rock). Dielectric permittivity is relatively high and remains constant during the dormant period, after that it decreases rapidly when the hydration reaction resumes and continues to decrease during the acceleratory period.

References

[1]  A. C. Metaxas, “Microwave Heating,” Power Engineering Journal, Vol. 5, No. 5, 1992, pp. 237- 247. http://dx.doi.org/10.1049/pe:19910047
[2]  K. Y. C. Leung and T. Pheeraphan, “Microwave Curing of Portland Cement Concrete: Experimental Results and Feasibility for Practical Applications,” Construction and Building Materials, Vol. 9, No. 2, 1995, pp. 67-73. http://dx.doi.org/10.1016/0950-0618(94)00001-I
[3]  R. G. Hutchinson, et al., “Thermal Acceleration of Portland Cement Mortars with Microwave Energy,” Cement and Concrete Research, Vol. 21, No. 5, 1991, pp. 795- 799. http://dx.doi.org/10.1016/0008-8846(91)90174-G
[4]  American Society for Testing and Materials, “Annual Book of ASTM Standard,” Vol. 4.01, Philadelphia, 2008.
[5]  Hewlett Packard Corporation, “Dielectric Probe Kit 85070 A,” Research and Development Unit, Test and Measurements Laboratories, Palo Alto, 1992.
[6]  P. C. Hewlett, “Lea’s Chemistry of Cement and Cementitious Material,” 4th Edition, John Wiley & Sons Inc., New York, 1998.
[7]  F. H. Wittmann and F. Schlude, “Microwave Absorption of Hardened Cement Paste,” Cement and Concrete Research, Vol. 5, No. 1, 1975, pp. 63-71. http://dx.doi.org/10.1016/0008-8846(75)90108-8
[8]  S. Wen and D. D. L. Chung, “Effect of Admixtures on the Dielectric Constant of Cement Paste,” Cement and Concrete Research, Vol. 31, No. 4, 2001, pp. 673-677. http://dx.doi.org/10.1016/S0008-8846(01)00475-6
[9]  H. C. Rhim and O. Buyukozturk, “Electromagnetic Properties of Concrete at Microwave Frequency Range,” ACI Materials Journal, Vol. 95, No. 3, 1998, pp. 262-271.

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