Table of Contents
Chinese Journal of Engineering
Volume 2016, Article ID 9714381, 7 pages
http://dx.doi.org/10.1155/2016/9714381
Research Article

An Experimental and Numerical Study on Embedded Rebar Diameter in Concrete Using Ground Penetrating Radar

Department of Civil Engineering, University of Texas at Arlington, P.O. Box 19308, Arlington, TX 76019, USA

Received 1 March 2016; Revised 23 June 2016; Accepted 21 July 2016

Academic Editor: Pierre-yves Manach

Copyright © 2016 Md Istiaque Hasan and Nur Yazdani. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

High frequency ground penetrating radar (GPR) has been widely used to detect and locate rebars in concrete. In this paper, a method of estimating the diameter of steel rebars in concrete with GPR is investigated. The relationship between the maximum normalized positive GPR amplitude from embedded rebars and the rebar diameter was established. Concrete samples with rebars of different diameters were cast and the maximum normalized amplitudes were recorded using a 2.6 GHz GPR antenna. Numerical models using GPRMAX software were developed and verified with the experimental data. The numerical models were then used to investigate the effect of dielectric constant of concrete and concrete cover on the maximum normalized amplitude. The results showed that there is an approximate linear relationship between the rebar diameter and the maximum GPR normalized amplitude. The developed models can be conveniently used to estimate the embedded rebar diameters in existing concrete with GPR scanning; if the concrete is homogeneous, the cover depth is known and the concrete dielectric constant is also known. The models will be highly beneficial in forensic investigations of existing concrete structures with unknown rebar sizes and locations.