Should priming be your prime consideration?
Want to glue concrete or seal a concrete constructing joint?
Upon looking at it, concrete may appear as a very dense, very homogeneous material. However upon looking closer, we see many small pores, thousands of them. Then again, what happens to the surface of the concrete during the drying process? During drying, a thin layer of excess water and cement, rises to the surface to form what is known as laitance.
Fresh concrete has a pH of approximately 13. At a pH of below 9, a process known as carbonation takes place due to the following reaction:
Ca (OH)2 + H2CO3 ►CaCO3 + 2H2O = Carbonation
Ca (OH)2 + H2SO4 ►CaSO4 + 2H2O = Carbonation
But what does this have to do with gluing or sealing concrete…..lots actually. Those pores, unless effectively sealed, will severely reduce adhesion and may lead to a total failure of the bonded or sealed concrete. Secondly, we must make sure that the concrete surface is ready to receive say a coat of adhesive or a bead of sealant.
First you need to start with concrete which is clean and dry. Very often, the first task may include vacuuming the concrete surface or at a very minimum using stiff brush to remove all loose material.
Priming the concrete surface, especially construction joints, is always the very best method of ensuring the optimum adhesion of a sealant.
We have developed several porous surface primers. These are based on our unique acrylic resin technology, the perfect partner for our silicone or polyurethane sealants. These primers are all brush or spray applied, and dry within two hours to form a heavy duty film which seal the concrete surface in a very effective manner.
Remember, the implementation of some simple surface preparation techniques, is always much cheaper than renovation! Speak to our Technical Service Department, we are always available.