AS 1012.5:2014 Methods of testing concrete
7.2 Compaction by vibration
Compaction by vibration shall be carried out as follows:
(a) Fill the measure in two approximately equal layers with the scoop. As each scoopful of concrete is being placed in the measure, move the scoop around the top edge of the measure as the concrete slides out, to ensure symmetrical distribution of concrete.
(b) Place all the concrete for each layer before commencing vibration.
(c) Vibrate each layer only long enough to achieve full compaction. Avoid over-vibration.
NOTE: The duration of vibration required to compact each layer will depend upon the workability of the concrete and the effectiveness of the vibrator. Usually the surface of the concrete becomes relatively smooth in appearance and substantial air bubbles cease breaking the surface when sufficient vibration has been applied. Extreme care should be taken to avoid segregation when using vibration to compact concrete with slump greater than 100 mm.
(d) Where an internal vibrator is used, compact each layer by four insertions of the vibrator at points symmetrically distributed over the cross-section of the measure. Do not allow the vibrator to rest on the bottom of the measure or to touch the sides of the measure. Take care to withdraw the vibrator in such a manner that no air pockets are left in the specimen. After vibrating the top layer, tap the sides of the measure sharply 10 to 15 times with the mallet.
(e) Where external vibration is used, rigidly attach or securely hold the measure against the vibrating element or vibrating surface.
(f) Add the top layer so as to avoid overfilling of the measure by more than 6 mm and thus losing excessive mortar by overflowing during vibration. After vibrating the top layer, some additional concrete may be added and worked into the surface with a float.
(g) Strike off the surface of the concrete and then finish smoothly with a flat glass cover plate to ensure that the concrete precisely fills the measure.