Cement based materials are highly alkaline due to the presence of calcium hydroxide i.e. they have a high pH. Unlike many other products the chemcial bond of a Dry-Treat sealers can withstand strong alkali attack from calcium hydroxide. The Alberta Transport & Utilities have developed a test to determine the ability of a sealing treatment to withstand alkali attack and that test has become the basis for similar performance based sealing specifications around the world. Their test involves soaking a treated sample of concrete in 0.1 molar solution of potassium hydroxide, which has a very high pH, for 21 days then testing the sample for water up-take. To date, the best performing material has been the Dry-Treat type of sealer.
