Pre-Concrete Repair Assessment Survey

Oxford City Council are conducting feasibility studies to consider the requirements to carry out Concrete Repairs to Oxford City Council Housing Blocks where the main construction is re-enforced concrete.

The first floor to the blocks are mainly accessed by stairwells to walkways and the first floor homes also have individual balconies.

There will be a requirement to carry out a detailed concrete assessment to our properties with balcony walkways/stair wells and to individual balconies predominantly to the first floor properties.

Some of the balconies have had previous remedial works which has included a covering of asphalt to the walkway surfaces.

The Balcony Soffits from primary visual inspections are displaying low cover to the steel reinforcement which may be the result of delamination to some sections of the balcony structures resulting in exposure of the re-enforcement notably to the soffit areas

A thorough assessment through visual, hammer and chemical assessment is required to BS EN 1504 to establish the catalysis for the possible corrosion to the steels and to consider the durability and strength of the concrete.

With the possibility of carbonation affecting parts of the concrete structure and with the requirement for laboratory samples and analysis testing this should be included within the quote.

It is important that the supplier inspects each site before submitting their price when considering the risk of corrosion to mitigating factors such as migrating or cast-in also the quality of the concrete and environmental effects and moisture content.

The assessments will also require visual survey and localised hammer/covermeter to exposed concrete areas, this will further establish the areas to be considered for chemical testing and to assess the level of but not limited to delamination, any spalling, honeycombing, efflorescence etc.

Drill and dust samples will be in accordance with Section 4.1 of BS EN 14629-2007

The depth of carbonation testing to be determined on site using phenolphthalein indicator solution to BS EN 14630:2006

Test for establishing chloride levels to BS EN 14629:2007

Recommended that supplier is UKAS Accredited

On the pricing schedule this should be used to establish your price for each site, quantities have been left blank where by the supplier will determine what test are required to produce the reports and recommendations.

The final report should consider any further requirements for investigations and chemical analysis before the recommended product specification is considered.

The total taken from each Block will determine the successful quote from the Total Summary of Quote on the Schedule of Works Tab