Comparative experiment to determine the waterproofness of concrete by "wet spot" and "breathability" methods
Comparative tests of control samples of concrete for water resistance by the direct method of "wet spot" and the method of "air permeability" were carried out. Tests of 6 series of control samples showed that 60 % of the results obtained by the two methods differ by 0.2 MPa (one brand of water resistance W), which is unacceptable. The range of results for the direct "wet spot" method was 0.6 MPa (four waterproof grade W), more than for the "air permeability" method 0.4 MPa (three grade W). Probably, this is due to the imperfection of test methods, with an insufficient level or lack of metrological confirmation of equipment for determining water resistance, and more. In production practice, this situation means that the test results obtained are not provided with confidence, and as a result, under these conditions, it is possible to produce products (concrete) that do not meet regulatory requirements.