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Cementitious Coating Resists Chlorides Almost 25 Years


Flexcrete Technologies Limited, the UK’s leading independent manufacturer of technical mortars and high performance coatings, has received official confirmation that its Cementitious Coating 851 will resist chloride penetration for at least 25 years.

In 1988, a 2mm thick film of Cementitious Coating 851 was applied to a concrete slice and sealed in a chloride ion diffusion cell in the laboratory at the VINCI Construction Technology Centre and it is still going strong some 25 years (9125 days) later. Tests recently carried out show that the barrier properties of 851 are such that a steady state of flux of chloride ions through the coated concrete has not been attained after a test period spanning 25 years, whereas the control concrete achieved this in just 28 days.

Cementitious Coating 851 is a high performance, two component, waterborne cementitious modified polymer coating which is ideal for the structural waterproofing of concrete, resisting positive and negative pressure under a 100 metre head.  It forms a hard, highly alkaline coating which not only protects concrete from the effects of aggressive acid gases, moisture and chlorides, but also has greatly enhanced chemical resistance.

851 also provides reinstatement of effective cover on precast and in-situ reinforced concrete, enhancing durability to achieve specified design life.  A 2mm coating of Cementitious Coating 851 is equivalent to 100mm of good quality concrete.  Being cement based, it chemically reacts with the substrate to form an integral part and will have a design life equivalent to that of the concrete to which it is applied. 851 can be applied to green concrete by brush or spray techniques, exhibits minimal hazard during application and is non-toxic when cured.

Chris Lloyd, Technical Director at Flexcrete Technologies Limited said: “It is excellent news that Cementitious Coating 851, one of our core products, has demonstrated such effective resistance to chlorides over this sustained period of time.  Chloride attack is one of the primary causes of damage in reinforced concrete structures exposed to de-icing salts and marine environments, so when engineers specify 851, they have the assurance that it will provide years’ of effective protection against corrosion of steel reinforcement.”

Flexcrete Technologies Limited is the UK’s leading independent manufacturer of technical mortars and high performance coatings. With origins dating back to 1983, the company manufactures a wide range of concrete repair mortars, fairing coats, waterproof cementitious coatings and decorative protective coatings.  With its head office and manufacturing complex based in Leyland, North West England, Flexcrete products are available from stockholding distributors all around the UK. The company also has a global presence through international agents and distributors in 65 countries worldwide with export sales accounting for over 50% of its business.