Can weather conditions affect the amount of material that is absorbed when a silane water repellent material is sprayed on concrete? I've read that on hot, windy days, so much silane may evaporate that the treatment has little effect.
Data published in an article in Concrete International (October, 1990) shows loss of material due to evaporation to be minimal. Author Edward McGettigan says absorption is a faster reaction than evaporation because capillary forces are stronger than any other participating factor. To prove this with test results, researchers heated concrete, brick, and stone specimens to a surface temperature of 176 F using quartz lamps. They treated the specimens at that temperature by pouring a silane solution directly on the surface. During the test period, samples also were exposed to a 7 mph wind. In absorption tests, water uptake of the treated specimens was then compared with that of untreated specimens. Untreated concrete specimens absorbed 15 times as much water as the silane-treated specimens. Similar results were obtained for the brick and stone.