Using radar direct wave for concrete condition assessment: Correlation with electrical resistivity

• Published in: Journal of applied geophysics Vol. 62; no. 4; pp. 361 - 374
• Main Authors: Sbartaï, Z.M., Laurens, S., Rhazi, J., Balayssac, J.P., Arliguie, G.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 01-08-2007; Amsterdam Elsevier; New York, NY
• Subjects: Applied geophysics; Concrete; Condition assessment; Corrosion risk; Direct wave; Earth sciences; Earth, ocean, space; Electrical resistivity; Exact sciences and technology; Internal geophysics; Radar; Concrete; Direct wave; Condition assessment; Electrical resistivity; Corrosion risk; Radar; concrete; waves; corrosion; probability; bars; contamination; saturation; correlation; radar methods; slabs; electrical resistivity
• ISSN: 0926-9851; 1879-1859
• DOI: 10.1016/j.jappgeo.2007.02.003

This paper demonstrates that the direct wave of a radar ground-coupled antenna may be used for the nondestructive assessment of the physical condition of concrete, which directly influences the corrosion of the reinforcing bars in the structure. The validity of this method was evaluated by a comparison with the electrical resistivity method, which is frequently used for the evaluation of corrosion probability. Both methods were implemented in the laboratory on 72 concrete samples (25
×
25
×
8 cm
3) with various degrees of saturation and chloride contamination levels. On-site investigations were also carried out on the concrete slab (1080 m
2) of a car-park.
The results of the laboratory tests show that the radar direct signal is strongly affected by variations in concrete moisture and chloride contamination level. The tests performed in real conditions confirm the good correlation between radar direct wave attenuation and electrical resistivity and, thus, the aptitude of the radar direct wave to detect concrete conditions leading to reinforcement corrosion.