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IMPORTANT CONSIDERATIONS FOR VIBRATOR USE

1) The vibrator should be used after concrete has been spread with a shovel. If concrete is transported with a vibrator, segregation occurs.

2) In shear walls and columns, concrete should be compacted in 50 cm layers.

3) Immersion vibrators should not be brought close to the formwork surface. Otherwise, nail-marked surfaces and sandy patches form on the formwork.

4) Prolonged contact of the vibrator with the reinforcement should be avoided. Otherwise, a very watery and weak slurry forms around the reinforcement, weakening bond (adhesion).

5) Vibration should cease as soon as water appears on the surface. Otherwise, cracks develop on the surface, or the layer between 2–4 cm below the top surface separates from the main concrete mass under a shell.

6) The vibrator should be inserted into the concrete as vertically as possible and withdrawn vertically.

7) The vibrator should be inserted into the concrete very slowly and withdrawn very slowly; otherwise a partial void (half-hole) remains.

  1. Settled concrete adjacent to the pour should not be disturbed during vibration.