Efficiency of Crystalline Coating Measured by Contact Angle Method

Abstract

The paper deals with two problems in the field of cement-based crystalline coating: The uncertainties about the depth effect of crystalline coating and the influence of curing on resulting waterproofing effect. For coating depth effect investigation the authors used a method based on the analysis of surface hydrophobicity (contact angle method). The depth effect of crystalline coating can be detected on the basis of the different surface hydrophobicity in various distances from the coated surface. The results of measurement showed that the tested crystalline coatings affect concrete microstructure to depth of approximately 50 - 60 mm (measured 4 months after the coating application). But it turned out that used method is not appropriate for this purpose because the results can be affected by a lot of influences and it is necessary be cautious about the conclusions. Another part of experimental program showed that the curing of crystalline coating during its ageing is absolutely necessary for the consequent waterproofing effect. This fact is also the risk factor for the using of crystalline coatings because the waterproofing effect is dependent on a consistent technological discipline.