The Form of Previous or Existing Repairs
Where concrete surfaces have been subjected previously to repair, in our opinion, the repairs should be investigated and the condition and methodologies employed assessed. These investigations may provide valuable information concerning the failure of the concrete surfaces leading to the need for repair. Such investigations will also enable a future repair strategy to be formulated, to employ the successes, but avoid the failures of the past.
Furthermore, if the previous or existing repairs are to remain in-situ somebody may be required to accept liability for them and essentially warranty them for a further period, in which case the data resulting from our assessments will be essential.
Previous or existing repairs will be subjected to close visual scrutiny and hammer tested. Notes concerning the following will be made:-
- Associations, i.e. are the repairs associated with anything in particular, e.g. structural edges, joints, or other such features
- Relative colour/s, parent substrate vs repairs
- Surface finish (trowelled, brushed, as-cast etc.)
- Evidence of curing
- Slumping and other plastic deformation
- Displacement, or ‘as-cast’ miss-alignments
- Cracking, micro-cracking and crazing, and any associated rust or other staining
- Delamination / hollowness
A limited selection of representative repairs will then be broken out, at least in part, in order to assess, as far as possible, the extent of such concrete patch-repair fundamentals as:-
- Preparatory breaking out (defects to repairs), feather-edging and squaring-off etc.
- If present (record if not), reinforcement cleaning and priming (Cautionary Note:- Older repairs may have been applied following treatment of the reinforcement with a paint, commonly red, but sometimes others colours such as orange or white, which may be lead-based paint.
- Concrete cleaning and priming
- Repair material type (cementitious vs resin / proprietary vs site mixed sand: cement vs site batched concrete / gunite)
- Repair depths and layering
- Repair material robustness, compaction and voids (record where any voids are, e.g. behind reinforcement and / or along layer interfaces
Detailed notes and record photographs will be prepared.