00625550

Component

http://onlinepubs.trb.org...trr/1992/1355/1355-012.pdf

https://scholar.google.co...Chan&publication_year=1992

In recent years considerable attention has been focused on the use of ground-penetrating radar (GPR) to detect a variety of pavement problems. The results to date have been mixed. Information on the electrical properties of highway materials is limited as is the ability to model the propagation of electromagnetic waves in a pavement system. A forward model capable of simulating the signature of GPR waveforms is proposed. A monostatic 1 GHz GPR is used in this study. The pavement system is modeled as a layered medium comprising flat parallel layers of pavement materials laminated together. Physical laws governing electromagnetic wave propagation inside the layered medium are used to calculate the attenuation, dispersion, reflection, and transmission encountered by the pulse. Major reflection paths and some multiple reflection paths are selected that begin from the open tip of the antenna, penetrate into the pavement, and reach the pavement surface again. The analysis is performed in each of these paths one at a time. The resultant echoes at the pavement surface are then positioned and superimposed together according to the time required for the pulse to travel each of the selected paths. A synthetic waveform is thus formed. This process is called forward modeling. The forward model is tested on data collected on experimental pavements of known layer thicknesses and types. Reasonable agreement was achieved between theoretically calculated and field-measured GPR traces. In predicting the amplitude of the waves reflected from layer interfaces average errors of less than 9% were calculated. The error in estimating the time delays between peaks was less than 2.5%. More work is required, particularly in the area of measuring the complex dielectric properties of paving materials under a range of operational temperature and moisture conditions.

This paper appears in Transportation Research Record No. 1355, Nondestructive Structural Evaluation of Pavements. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01405034

English

p. 99-107

1992

Transportation Research Record

030905219X

Figures (14) ; References (6) ; Tables (1)

Accuracy; Future; Ground penetrating radar; Pavements; Research; Wave motion

Future research

Design; Highways; Pavements; Research; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces

TRIS, TRB, ATRI

Dec 16 1993 12:00AM

• ALTERNATIVE METHOD FOR TEMPERATURE CORRECTION OF BACKCALCULATED EQUIVALENT PAVEMENT MODULI
• COMPREHENSIVE EVALUATION OF FIVE SENSORS USED TO MEASURE PAVEMENT DEFLECTION
• EFFECT OF DEPTH TO BEDROCK ON DEFLECTION BASINS OBTAINED WITH DYNAFLECT AND FALLING WEIGHT DEFLECTOMETER TESTS
• EFFECTS OF BUFFERS ON FALLING WEIGHT DEFLECTOMETER LOADINGS AND DEFLECTIONS (WITH DISCUSSION)
• ESTIMATING DAMAGE EFFECTS OF DUAL VERSUS WIDE BASE TIRES WITH MULTIDEPTH DEFLECTOMETERS
• EVALUATION OF A DUAL-LOAD NONDESTRUCTIVE TESTING SYSTEM TO BETTER DISCRIMINATE NEAR-SURFACE LAYER MODULI
• FIELD AND LABORATORY DETERMINATION OF ELASTIC PROPERTIES OF PORTLAND CEMENT CONCRETE USING SEISMIC TECHNIQUES
• NONLINEAR EFFECTS IN FALLING WEIGHT DEFLECTOMETER TESTS
• RADAR PAVEMENT THICKNESS EVALUATIONS FOR VARYING BASE CONDITIONS
• SIMPLIFIED, RATIONAL APPROACH TO FALLING WEIGHT DEFLECTOMETER DATA INTERPRETATION
• VARIABILITY IN ESTIMATION OF STRUCTURAL CAPACITY OF EXISTING PAVEMENTS FROM FALLING WEIGHT DEFLECTOMETER DATA