CONCRETE PLACEMENT IN HOT WEATHER

1) Particularly in areas where reinforcement is dense, formwork with high thermal conductivity should not be used for reinforced concrete.

2) Before concrete placement begins, formwork and reinforcement must be thoroughly wetted.

3) If concrete is being placed on natural ground, the ground must be pre-compacted, levelled, and thoroughly wetted to prevent absorption of the mixing water by the subsoil.

4) Concrete should be placed in the evening or at night; morning placement should be avoided.

5) Concrete must be placed within 90 minutes of mixing. If necessary, this period may be extended by incorporating a set-retarding admixture into the concrete.

6) Adding 10 litres of water per 1 m³ of concrete on site causes approximately an 8% reduction in compressive strength.