Problem Solving Forum
March 26 - March 30, 2018
What is the best way to protect an exposed concrete foundation?
Selected Answers
From
KARL BRINKMANN of PURE ASPHALT on
March 27, 2018:
We have had good luck with a tri-polymer gre ...read more
We have had good luck with a tri-polymer grey and beige foundation coating, which has high tensile strength, but remains somewhat elastic. It has excellent UV resistance and can be sprayed or rolled on. It is the best product we have ever seen for this type of application, paintable, too.
From
Zenith Czora of Durotech Industries, Inc. on
March 27, 2018:
Depending on the location and purpose of the concr ...read more
Depending on the location and purpose of the concrete foundations, they are subjected to wide range of exposure conditions: atmospheric carbonation, polluted urban/industrial environment, and marine and chemical atmosphere, all of which can damage the concrete and its embedded steel reinforcement. Carbonation occurs when carbon dioxide reacts with calcium hydroxide and deposits as calcium carbonate, which reduces the protection of embedded steel reinforcement. Chloride ingress, in which chloride ions from the de-icing salts or from salt water, can penetrate into the concrete structure and can cause fast pitting corrosion of the reinforcement bars. The faster CO2 and chlorides penetrate into the concrete, the more severe will be the aggression. A barrier coating which has anti-carbonation properties and inhibits chloride ion diffusion is recommended. A barrier coating must comply with the threshold of EN1504-2 (Sd = 50m) and infinitive value of Sd for complete protection against carbonation protection. Others parameters to consider for a barrier coating are permeability to water vapour, crack-bridging capability, and elongation and tensile strength properties for film elasticity. Different types of barrier coatings are acrylic elastomeric coating, elastic polymer-modified cement-based, hybrid coating (either modified with silicone or polyurethane or both). For UV light stability and color retention, elastic polyurethane coatings perform well. For marine environment, the coating system should be high solid or 100% solid epoxy topcoated with an elastic polyurethane coating.