Preparation of Concrete Affected by Carbonation

All the relevant product data sheets are to be read for additional information like pot life, mixing instructions, surface preparation, ventilation, temperature application limitations, etc.

The agreed area shall be broken out to remove all contaminated concrete. Where the depth corresponds to the depth of concrete cover and thereby exposes reinforcement, breaking out shall continue to expose the full circumference of the steel and to a further depth of 25 mm or as directed by the Contract Administrator.

Breaking out shall continue along the reinforcement until non-corroded steel is reached and shall continue 50 mm beyond this point or as directed by the Contract Administrator. Special care shall be exercised to ensure that any reinforcement exposed is not cut or damaged.

After breaking out as specified the exposed surface of concrete shall be tested for carbonation by the use of a semi-aqueous solution of phenolphthalein. The test shall be carried out on the freshly exposed concrete or at least within 30 minutes of being exposed. The test shall be carried out on sound, dry and clean airblown dust free surfaces. If the concrete substrate still exhibits carbonation in the vicinity of the steel reinforcement, breaking out to remove a further 20 mm shall be carried out and the test repeated. If carbonation is still present the Contract Administrator shall be notified before proceeding further.

It is essential that no carbonated concrete substrate shall be in contact with, or within 5 mm of, the reinforcing bars. In cases where carbonation has reached within 5 mm of the reinforcing bars, the concrete shall be broken out to expose the full circumference of the steel and a further depth of 20-30 mm or as directed by the Contract Administrator.

Where the use of a.b.e.®s spalling repair is specified for a repair area, breaking out carbonated concrete will be limited to areas subject to spalling.

Important Note

This data sheet is issued as a guide to the use of the product(s) concerned. Whilst a.b.e.® Construction Chemicals endeavors to ensure that any advice, recommendation, specification or information is accurate and correct, the company cannot – because a.b.e.® has no direct or continuous control over where and how a.b.e.® products are applied – accept any liability either directly or indirectly arising from the use of a.b.e.® products, whether or not in accordance with any advice, specification, recommendation, or information given by the company.

Further Information

Where other products are to be used in conjunction with this material, the relevant technical data sheets should be consulted to determine total requirements. a.b.e.® Construction Chemicals has a wealth of technical and practical experience built up over years in the company’s pursuit of excellence in building and construction technology.