BS EN 12390-2:2019 pdf free
BS EN 12390-2:2019 pdf free.Testing hardened concrete Part 2: Making and curing specimens for strength tests.
The sample shall be taken in accordance with EN 12350-1.
The sample shall be re-mixed, using the remixing container or tray and shovel, before filling the moulds.
NOTE Where specimens are to be manufactured away from the sampling location, they may be transported to the place of manufacture provided the sample is protected from dehydration and remains capable of being re-mixed.
6 Procedures
6.1 Preparation and filling of the moulds
6.1.1 Where necessary, before filling the mould, the inner surface of the mould should be covered with a thin film non-reactive release material to prevent the concrete from adhering to the mould
6.1.2 Depending on the consistence of the concrete, the height of the mould and the method of compaction, moulds shall be filled in as many layers as necessary to achieve full compaction. In the case of self-compacting concrete, the mould shall be filled in one operation and no compaction shall be applied during filling or after the mould is filled.
6.1.3 If a filling frame is used, the amount of concrete used to fill the mould shall be such that a layer of concrete remains in the filling frame after compaction. The thickness of this layer shall be 10 % to 20 % of the height of the test specimen.
6.2 Compaction of the concrete
6.2.1 General
The concrete shall be compacted immediately after placing in the moulds in such a way as to produce full compaction of the concrete with neither excessive segregation nor laitance. Each layer shall be compacted by using one of the methods described in 622 and &2..,3.
NOTE Full compaction is achieved using mechanical vibration, when there is no further appearance of large air bubbles on the surface of the concrete and the surface becomes relatively smooth with a glazed appearance, without excessive segregation.
Further guidance on methods of compaction for concretes having different consistencies or cast in different sizes or types of moulds, may be given in provisions valid in the place of use of the concrete.
6.2.2 Mechanical vibration
6.2.2.1 Compacting with internal vibrator
Apply the vibration for the minimum duration necessary to achieve full compaction of the concrete. Avoid over-vibration, which may cause loss of entrained air.BS EN 12390-2 pdf free download.
