RoofKrete

Carbonisation

Carbonisation Simply Explained

Carbonation is the penetration of carbon dioxide from the atmosphere into the interior of concrete. This causes the reinforcing metal to rust and fail even in good quality concrete structures as the pore water within the concrete is converted to carbonic acid. This rust builds up pressure which forces off the covering layer of about 20 mm exposing the reinforcing bar. Urgent and expensive remedial treatment is then required. 

The normal laboratory test for testing the depth of carbonation is by using  a Phenolphthalein indicator. - When RoofKrete was tested using an 11 year old sample the depth recorded was less than 0.1mm. The testing laboratory at Portsmouth University concluded that the material would carbonate to a depth of 0.2mm in 50 years!

The cover on RoofKrete System 4 is about 1.5 mm this gives a carbonation penetration rate of about 750 years before it reaches the metal reinforcing! But even if carbon dioxide penetrated to the metal there is no pore water present in RoofKrete to cause rust!