A Study of Concrete Hydration and Dielectric Relaxation Mechanism Using Ground Penetrating Radar and Short-Time Fourier Transform

Ground penetrating radar (GPR) was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC) hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT) in joint time-frequency analysis (JTFA) domain rather than a conventional time or frequency domain alone. The signals of the direct wave traveled at the concrete surface and the reflected wave from an embedded steel bar were transformed with STFT, in which the changes of peak frequency over ages were tracked. The peak frequencies were found to increase with ages and the patterns were found to match closely with primarily the well-known OPC hydration process and secondarily, the evaporation effect. The close match is contributed to the simultaneous effects converting free to bound water over time, on both conventional OPC hydration and dielectric relaxation mechanisms.

[1]  A. P. Annan.  Chapter 1 – Electromagnetic Principles of Ground Penetrating Radar , 2009 .

[2]  W. L. Lai,et al.  Characterization of pore systems of air/water-cured concrete using ground penetrating radar (GPR) through continuous water injection , 2008 .

[3]  Allan J. Delaney,et al.  Dielectric properties of soils at UHF and microwave frequencies 36R. J. Geophys. Res. V79, N11, Apr. 1974, P1699–1708 , 1974 .

[4]  Chi Sun Poon,et al.  Characterization of concrete properties from dielectric properties using ground penetrating radar , 2009 .

[5]  W. L. Lai,et al.  Experimental determination of bulk dielectric properties and porosity of porous asphalt and soils using GPR and a cyclic moisture variation technique , 2006 .

[6]  Yi Huang,et al.  Radar frequency dielectric dispersion in sandstone: Implications for determination of moisture and clay content , 2003 .

[7]  A. P. Annan,et al.  Electromagnetic determination of soil water content: Measurements in coaxial transmission lines , 1980 .

[8]  K. Cole,et al.  Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics , 1941 .

[9]  Fawwaz T. Ulaby,et al.  Dielectric properties of soils in the 0.3-1.3-GHz range , 1995, IEEE Trans. Geosci. Remote. Sens..

[10]  A. Hippel,et al.  Dielectric Materials and Applications , 1995 .

[11]  Pieter Hoekstra,et al.  Dielectric relaxation of surface adsorbed water , 1971 .

[12]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part II: Dielectric Mixing Models , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[13]  A. P. Annan,et al.  Measuring Soil Water Content with Ground Penetrating Radar: A Review , 2003 .

[14]  V. M. Malhotra,et al.  CRC Handbook on Nondestructive Testing of Concrete , 1990 .

[15]  S. Qian,et al.  Joint time-frequency analysis : methods and applications , 1996 .

[16]  J. Rhazi,et al.  Non-destructive evaluation of concrete moisture by GPR: Experimental study and direct modeling , 2005 .

[17]  A. van Beek,et al.  Dielectric properties of young concrete: Non-destructive dielectric sensor for monitoring the strength development of young concrete , 2000 .

[18]  Michael David Knoll,et al.  A petrophysical basis for ground penetrating radar and very early time electromagnetics : electrical properties of sand-clay mixtures , 1996 .

[20]  J. H. Bungey,et al.  SUB-SURFACE RADAR TESTING OF CONCRETE: A REVIEW , 2004 .

[21]  Allan J. Delaney,et al.  Dielectric properties of soils at UHF and microwave frequencies , 1974 .

[22]  G. P. de Loor,et al.  The Dielectric Properties of Wet Materials , 1983 .

[23]  M. A. K. Hamid,et al.  Monitoring of Concrete Curing Process by Microwave Terminal Measurements , 1972, IEEE Transactions on Industrial Electronics and Control Instrumentation.

[24]  Steve Millard,et al.  Dielectric properties of concrete and their influence on radar testing , 2000 .

[25]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part 1: Empirical Models and Experimental Observations , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[26]  P. D. Waal,et al.  Use Of V.h.f Dielectric Measurements For Borehole Formation Analysis , 1978 .

[27]  M B Dusseault,et al.  High-frequency complex permittivity of shales (0.02-1.30 GHz) , 1998 .

[28]  Doreen Streicher,et al.  Results of reconstructed and fused NDT-data measured in the laboratory and on-site at bridges , 2006 .

[29]  Julie Q. Shang,et al.  Dielectric Constant and Relaxation Time of Asphalt Pavement Materials , 1999 .

[30]  A. P. Annan.  11. Ground-Penetrating Radar , 2005 .

[31]  Mk Meint Smit,et al.  Microwave study of hydrating cement paste at early age , 1982 .

[32]  Imad L. Al-Qadi,et al.  Optimization of antenna configuration in multiple-frequency ground penetrating radar system for railroad substructure assessment , 2010 .

[33]  Nigel J. Cassidy,et al.  Chapter 2 – Electrical and Magnetic Properties of Rocks, Soils and Fluids , 2009 .

[34]  G. Klysz,et al.  Determination of volumetric water content of concrete using ground-penetrating radar , 2007 .

[35]  M. Forde,et al.  Review of NDT methods in the assessment of concrete and masonry structures , 2001 .

[36]  Ping Gu,et al.  Dielectric behaviour of hardened cementitious materials , 1997 .

[37]  A. Shaaria,et al.  Modelling the propagation of a radar signal through concrete as a low-pass filter , 2004 .

[38]  Hong C. Rhim.  Condition monitoring of deteriorating concrete dams using radar , 2001 .

[39]  A. P. Annan,et al.  Ground-penetrating radar for high-resolution mapping of soil and rock stratigraphy , 1989 .

[40]  Jens Wöstmann,et al.  Investigation of dielectric properties of brick materials as a function of moisture and salt content using a microwave impulse technique at very high frequencies , 1998 .

[41]  S. Friedman.  A saturation degree‐dependent composite spheres model for describing the effective dielectric constant of unsaturated porous media , 1998 .

[42]  T. Schmugge,et al.  An Empirical Model for the Complex Dielectric Permittivity of Soils as a Function of Water Content , 1980, IEEE Transactions on Geoscience and Remote Sensing.

[43]  D. Daniels.  Ground Penetrating Radar , 2005 .