MEASUREMENT OF THE DEPTH OF SURFACE OPENING CRACKS USING IMPACT-ECHO METHOD

Abstract eng:
Currently, the widths of opening surface cracks in reinforced concrete structures are used together with carbonation depth or chloride effects as an evaluation index for decision making for the repair of construction together with assessment of structural safety and ageing The crack depth as a more important factor for structural lifetime management is rarely incorporated in the codes due to lack of knowledges and experiences. The time-of-flight diffraction technique developed in the early 1980s has been used widely to locate and measure defects in metal using ultrasound. In contradiction concrete is a composite material consisting of a binding material with particles like gravel, sand etc. embedded in construction medium. To overcome these difficulties, stress waves generated by mechanical impact instead of an ultrasonic transmitter are used. In this paper is presented simply method based on the propagation of the dilatation (P) and Rayleigh (R) waves excited by the impact. The theory is applied to the cracks perpendicular and oblique to the surface.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket