Detection of chemical damage in concrete using ultrasound

✍ Scribed by S. Ould Naffa; M. Goueygou; B. Piwakowski; F. Buyle-Bodin

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 257 KB
• Volume: 40
• Category: Article
• ISSN: 0041-624X
• DOI: 10.1016/s0041-624x(02)00146-4

✦ Synopsis

This research deals with a non-destructive method for characterizing the degraded cover of concrete structures using high-frequency ultrasound (0.5-1 MHz). Although such a frequency range is unusual in civil engineering, it is well suited to the kind of defect to be detected, as it corresponds to a thin near-to-surface layer with increased porosity and density of microcracks. In order to assess the feasibility of detecting concrete cover degradation, velocity and attenuation measurements were made on both halves of a concrete slab. One half was immersed into an acid solution for 15-45 days, while the other half remained sound. These measurements were made for longitudinal, transverse and surface waves. The results obtained show a 23% decrease of ultrasonic pulse velocity and a 1000% increase of attenuation in the degraded material relative to the sound material. It is thus possible to detect and characterize concrete cover degradation using high-frequency ultrasound. Although attenuation measurements in heterogeneous media are difficult, their sensitivity to degradation is very high.