**Concrete Nondestructive Testing Methods**

186 Nondestructive Testing Methods and New Applications

Vértesy G., Tomáš I., Kobayashi S., Kamada Y. (2008b) Investigation of thermally aged

Vértesy G., Tomáš I., Takahashi S., Kobayashi S, Kamada Y, Kikuchi H., (2008c) Inspection

Vértesy G., Uchimoto T. Tomáš I., Takagi T. (2010a) Temperature dependence of magnetic descriptors of Magnetic Adaptive Testing, *IEEE Trans..Magn.*, Vol. 46. pp. 509-512 Vértesy G., Uchimoto T. Tomáš I., Takagi T. (2010b) Nondestructive characterization of

Vértesy G., Uchimoto T., Takagi T., Tomáš I. (2010c) Nondestructive inspection of ductile

Vértesy G., Ueda S., Uchimoto T., Takagi T., Tomáš I., Vértesy Z. (2011) Evaluation of Plastic

Vértesy G., Tomáš I. (2012a) Complex characterization of degradation of ferromagnetic materials by Magnetic Adaptive Testing, *IEEE Trans. Magn.*, in press Vértesy G., Tomáš I. Uchimoto T., Takagi T. (2012b) Nondestructive investigation of wall

pp.82-85

3117-3121

Amsterdam

Vol. 41. pp. 252-257

*Forum*, Vol. 659. pp. 355-360

INTERNATIONAL, Vol 47. pp. 51-55

samples by Magnetic Adaptive Testing, *Journal of Electrical Engineering,* Vol. 59.

of steel degradation by Magnetic Adaptive Testing, NDT & E INTERNATIONAL,

ductile cast iron by Magnetic Adaptive Testing, *J. Magn. Magn. Mater.* Vol. 322 pp.

cast iron by measurement of minor magnetic hysteresis loops, *Materials Science* 

Deformation in Steels by Magnetic Hysteresis Measurements, In: *Electromagnetic Nondestructive Evaluation (XIV)*, T. Chady et. al., Eds., pp. 371-378, IOS Press,

thinning in layered ferromagnetic material by magnetic adaptive testing, NDT & E

**8** 

*1Greece 2Malaysia 3Japan* 

**Elastic Waves on Large** 

D. G. Aggelis1, H. K. Chai2 and T. Shiotani3

*3Graduate School of Engineering, Kyoto University* 

**Concrete Surfaces for Assessment of** 

*1Materials Science & Engineering Department, University of Ioannina,* 

*2Department of Civil Engineering, Faculty of Engineering, University of Malaya* 

Most of society's infrastructure supporting certain sectors of human activity is based on cementitious materials. Bridges, highways, water intake facilities and other structures are made of concrete. These structures sustain external function loads, own weight, as well as deterioration by temperature cycles and attack of environmental agents during their useful life span. The number of civil infrastructures built more than 50 years ago may be estimated to several hundreds of thousands worldwide (Chai et al. 2010). The operational efficiency of these structures is of primary importance for economic reasons but mostly for human safety. Concrete structures have ceased to be considered maintenance-free. They should be inspected in regular intervals, their damage level should be evaluated and when necessary, repair action should be applied. Maintenance or repair projects should be based on prioritization as to the importance of the structure and its damage status. Therefore, economic, fast and reliable characterization schemes are highly demanded. In most of the currently available methods of assessment, elastic modulus of material and strength characteristics are the primary criteria of consideration. In order for the information to be obtained, it often becomes necessary that mechanical tests are conducted on samples acquired from the target structure, through extraction of cores or other similar exercises, which turn out to be inflicting further damage to the already-degraded target structure. In addition, considering the nature of these exercises, which are usually adopted at selected locations, the assessment results are local and often not representative for the overall structure. Recently, extensive research has been reported in elastic wave-related techniques resulting in reliable assessment of the structural condition of actual concrete materials and structures. The characterization of concrete structures by Non Destructive Testing (NDT) and specifically stress wave methods produces mainly qualitative but very important results concerning damage. The surface layer of concrete suffers the most of environmental degradation as well as maximum stresses particularly by flexural loading. It is reasonable

**1. Introduction** 

**Deterioration and Repair Efficiency** 
