Non-linear Ultrasonic Spectroscopy as an Assessment Tool for the Structure Integrity of Concrete Specimens

M Korenska,M Matysik

doi:10.2478/v10158-010-0003-3

Abstract

On the basis of non-linear effect studies, new diagnostic and defectoscopic methods have been designed which are based on the elastic wave non-linear spectroscopy. The non-linear ultrasonic spectroscopy brings new prospects into the acoustic non-destructive testing of material degradation. Poor material homogeneity and, in some cases, the shape complexity of some units used in the building industry, are heavily restricting the applicability of "classical" ultrasonic methods. These linear acoustic methods focus on the energy of waves, which are reflected by structural defects, variations of the wave propagation velocity, or changes in the wave amplitude. However, none of these "linear" wave characteristics is as sensitive to the structure defects as the specimen non-linear response. In this way, non-linear methods thus open new horizons in non-destructive ultrasonic testing, providing undreamed-of sensitivities, application speeds, and easy interpretation. One of the fields in which a wide application range of non-linear acoustic spectroscopy methods can be expected is civil engineering. It is predicted that these advanced techniques can contribute a great deal to the improvement and refinement of the defectoscopic and testing methods in the building industry. The present paper deals with analyzing one of the non-linear ultrasonic defectoscopic methods from the viewpoint of its application to the concrete specimen structural integrity evaluation. Both intact specimens and specimens subject to various kinds of stress have been tested. The effect of structural defects on the elastic wave propagation has been studied.

Highlights

Thanks to the turbulent development of concrete and reinforced concrete buildings taking place in the last century, the condition of concrete and reinforced concrete became a hot topic in the last decade
On the basis of non-linear effect studies, new diagnostic and defectoscopic methods have been designed which are based on the elastic wave non-linear spectroscopy (Abeele and al. 2000, Johnson, 1999)
Our experimental and theoretical research work on Non-linear ultrasonic spectroscopy is focused on investigating non-linear ultrasonic transmission through building components from different inhomogeneous materials, such as ceramic, concrete, and reinforced concrete (Korenska & Manychova, 2008)

Summary

INTRODUCTION

Thanks to the turbulent development of concrete and reinforced concrete buildings taking place in the last century, the condition of concrete and reinforced concrete became a hot topic in the last decade. On the basis of non-linear effect studies, new diagnostic and defectoscopic methods have been designed which are based on the elastic wave non-linear spectroscopy Various papers have been published on the theoretical or experimental verification of different methods in some application areas. Most published papers, as well as our experience, show these methods to be highly promising for both defectoscopy and material testing purposes in the near future. Our experimental and theoretical research work on Non-linear ultrasonic spectroscopy is focused on investigating non-linear ultrasonic transmission through building components from different inhomogeneous materials, such as ceramic, concrete, and reinforced concrete (Korenska & Manychova, 2008)

EXPERIMENTAL ARRANGEMENT

Intact Concrete Specimens

Measurement Results

CONCLUSION