However, when in doubt water testing is a must. If the cracks contain algae, chlorinated water containing copper sulfate is injected. After pumping this mixture is left over night. The next morning the crack is flushed by pumping fresh water, into it. This flushes it out before resin injection begins.
Efflorescence builds up on the bottom of a crack in a horizontal slab.
Water in the crack extracting soluble calcium hydroxide is the cause. The water evaporates at the surface leaving the lime, which later reacts with the carbon dioxide in the air to form limestone. The inside of the crack, is frequently free of limestone and making it suitable for injection. Epoxy Resin Properties Epoxy Injection Resin should be ASTM C881 Type 1 Grade 1 . For maximum filling of cracks a low viscosity injection resin must be used.