Delamination surveys are important in identifying areas where the concrete face has debonded from the main substrate of the concrete which can be for a variety of reasons but is generally associated with corrosion of the reinforcement or water penetration. Delamination of concrete is a serious problem both for the integrity of the structure and from a Health and Safety aspect. Whilst delaminated concrete can be readily observed in many instances it is not always obvious without undertaking a delamination survey which involves tapping the concrete with a survey hammer at regular intervals to determine the extent of the defective concrete. The perimeter of the defective area needs to be identified and quantified.
On completion of the inspection and delamination survey and associated concrete sampling and testing it is recommended that the areas of defective concrete be recorded and quantified in a Schedule of Defects.
Areas requiring concrete repairs should be included in a Schedule of Defects which can be readily converted into a Bill of Quantities in accordance with the Concrete Repair Association Standard Method of Measurement in order to obtain competitive tenders for concrete repairs. It is important that the defective areas are identified regarding size, orientation (vertical, soffit, horizontal), depth and whether either vertical or horizontal arrisses are required to be formed. All of the above have a direct bearing on the cost of the repairs and enable tenders to be sought on a competitive basis and also enable a re-measure of the completed works.