ABSTRACT
Tests have been done in the USA(7) and Finland(8) where 100mm concrete cubes have been coated and submerged in water or salt solutions for up to 21 days followed by a period of drying. See Figure 3 for results of typical coatings(8) which show the much better performance of coatings (less than 35g/m2/√hr) compared with the reference concrete which had an absorption rate of 370 g/m2/√hr. This Figure also shows the slower rate of drying compared with the rate of absorption. However, these tests have also shown some surface treatment materials to have no advantage over bare concrete but it must be more difficult to get a defect free coating on six sides of a cube than on a single face of a slab. Furthermore, complete submergence is not typical of real exposure of an atmospheric surface and capillary absorption in all directions into a cube is a much more complex mechanism than that into a single surface.
