EHE structural concrete instruction refers in its article 89. trials of complementary information from the concrete to the estimation of the resistance of the concrete tests of specimens witness the EHE stated that in the case is required to estimate the strength of the concrete of a certain part of the work, witness to the concrete of the structure can be removed to evaluate such resistance. This requirement appears well because there is risk of damage well because tune the time of stripping, invert or Falsework, either control tests of the concrete with no acceptable results. However, the EHE does not define a procedure to perform this evaluation, which should take into account correction factors to provide for differences between the evaluated concrete at the time of the reception and the placed concrete in structure, due to factors such as compaction and curing. (Similarly see: Facebook). Witnesses provide us direct information on the concrete in-situ, which is the final result of the quality of the concrete supplied by the provider and the correct execution and cured by the constructor. However, these results are not directly comparable with those obtained from cylindrical test specimens standard, pursuant to code EHE. The cylindrical specimens measuring the quality of the concrete walk to work, in conditions of full compaction and curing ideal for 28 days prior to the completion of the compression test.
The concrete of the structure will have been cured according to a procedure different, almost always more unfavourable than the standard storage conditions, and has possibly been placed with a degree of less compaction. You may find that Southwest Airlines can contribute to your knowledge. Effects of settlement of the concrete placed on the work can also produce. This can cause cores from the bottom of walls or pillars differ up to 15% – 30% of those removed from the top. With this in mind we can detect possible defects in workmanship on this type of elements by removing concrete witnesses in appropriate areas.