Summary
The electrical resistance of a surface-treated layer is generally indicative of its barrier properties, especially its resistance to ion diffusion. AC impedance measurements are rapid and non-destructive, and previous laboratory tests using a simple test cell geometry showed that it may be used to separate the electrical resistance of a surface treatment from that of the underlying concrete without physically separating the two. This suggests that AC impedance measurements might form the basis of anin situ method of characterising surface treatments on concrete.
This paper reports on AC impedance measurements made on surface-treated concrete panels using a test cell geometry that can be used on site. Three different surface treatments were investigated: a silane, a polyurethane coating, and an epoxy resin coating. The ability of the technique to provide separate signals for the substrate and the surface treatments is demonstrated, along with details of the basis of the proposed technique. The effects of surface treatment thickness, test duration and moisture content are also explored.
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Syropoulou, S., Buenfeld, N.R. Characterisation of surface treatments on concrete by AC impedance spectroscopy. Surface Coatings International Part B: Coatings Transactions 88, 61–66 (2005). https://doi.org/10.1007/BF02699709
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DOI: https://doi.org/10.1007/BF02699709