Building & Civil Engineering Structures - Refurbishment Problems & Solutions

(1) Due to carbonation, localised corrosion of the reinforcement had occurred, resulting in spalling of the concrete cover. Left untreated, the design life of the structure would have been shortened.

Following removal of unsound concrete and preparation of the steel, 2 coats of Steel Reinforcement Protector 841 are applied by brush. Missing or removed concrete is then reinstated. Where a high build structural repair mortar is required, Monomix is the best choice. For general purpose repairs, Monolite, a low density mortar can be used. Monolite can be applied in thicknesses up to 100mm in a single layer Afterwards, Monolevel FC may be applied to all surfaces using a bag rubbing technique to achieve a fair-faced finish, prior to the application of a decorative anti-carbonation coating such as Monolastex Smooth.

(2) Extensive corrosion caused by chlorides, resulting in loss of steel section and large areas of spalling. The source can be chlorides which are cast-in, or those which ingress from external sources such as de-icing salts.

Unsound concrete is removed and the prepared steel is given 2 coats of Steel Reinforcement Protector 841 by brush.  Monomix can be hand applied to re-profile small areas of damage and a special grade, Monomix WS, is available for application by wet process in larger areas. Where shutters can be used for large repairs, Monopour, available as a pourable grout (PG) and a pourable concrete (PC6), is suitable. Cemprotec MCI® 2020 will diffuse through the concrete structure to form a protective layer on the reinforcement to protect it from corrosion in chloride contaminated structures.

(3) To give proven protection against carbonation and so extend the design life of a reinforced concrete structure. Such a barrier prevents further corrosion of steel reinforcement and subsequent spalling of the surrounding concrete.

Following repair, the complete structure is treated with Monolastex Smooth, a coating with outstanding anti-carbonation properties. This highly aesthetic coating also has excellent weathering and UV resistance and a serviceable life of at least 15 years.

Where aesthetics are of lesser importance, two 1mm coats of Cementitious Coating 851 will also provide long term protection for the design life of the structure.