Quantitative non-destructive evaluation of rebar diameter and corrosion damage in concrete using ground penetrating radar.

摘要

The purpose of this study is to develop new methods for quantitative estimation of rebar diameter and loss of area of rebar due to corrosion using Ground Penetrating Radar (GPR). The existing methods of determining the rebar diameter using GPR are not accurate and the existing methods for evaluating corrosion using GPR are qualitative. The study included in this dissertation uses a 2.6 GHz antenna to estimate the diameter of rebar using two different approaches. The approaches use digital image processing of GPR ragargrams and maximum normalized reflection amplitude form the rebar to estimate the diameter. A novel method to simulate corroded concrete beam specimen in the lab at different level of corrosion using oil water emulsion and accelerated corrosion of rebar in salt water solution.;The results of the diameter estimation using digital image processing shows that the 2.6 GHz antenna can estimate the size of ;Linear regression equations are developed to find the quantitative loss of area of the rebar at different stages of corrosion from the accelerated corrosion test in the laboratory. The regression equations are developed at three different dielectric constant of the medium and three different depth of concrete cover. A guideline is proposed on how to use the regression equation in the field to estimate the amount of area loss due to corrosion.