Concrete is concrete! All I need is cement in the mix, the more cement the better it will be! Granted, cement is pretty important and by far the pivotal ingredient in every concrete mix. But getting the best (or at least just the desired performance) from each different type of concrete is just a teamwork. Different type of concrete? If you are curious please read my post “Concrete, one for all?”
Back to business…Why concrete is a “teamwork”? Well concrete is a semi-finished product, which means that the concrete manufacturer is responsible for the quality and the quantity of the delivered concrete, but the building enterprise, by means of its labor, has the responsibility to allow the concrete expressing all its potential in favor of the structures to be built with it.
Here are some factors to be taken seriously into consideration:
Distance from the manufacturer to the building site. The concrete (if not specifically designed for this specific instance) starts immediately its setting reactions, so the more distant the building site, the lower the quality of the concrete delivered.
Season. Cement hydration suffer temperature. This is something that must be taken into consideration when managing the number of men at the casting and the speed in pouring the concrete out, just to mention few examples. Cooperation with the manufacturer implies even specific request for a seasonal concrete.
Workers´ speed/skill ratio. Depending on this factor it will be more/lesser reasonable to expect for fast casting with good quality level. This implies that the quantity of the concrete purchased for each and every batch should be modulated according to this ratio.
Building site logistic. When a casting is to be performed there should be no interference that can create waste of time, or interruption of the casting. The casting must be continuous, not interrupted.
Unexpected events. Funny enough, but the unexpected should be expected! Good coordination before the casting implies having ready plan B and plan C to ensure the continuity of the casting.
The choice of the correct consistency class. Please read my post “Workability of concrete”.
When it´s too hot and sunny the reinforcement bars will be burning hot. When the fresh concrete will meet them, it will immediately dry compromising its qualities and the adherence with the reinforcement bars themselves. It´s a good idea to refresh the reinforcement bars before the casting, spraying fresh water on them.
Considering that the concrete should be casted the closer possible to its final destination (more about that on my post “Concrete segregation”), it is vital to choose beforehand the proper mean for casting. Concrete pump, crane bucket and so on.
Compaction is an art. This is one of the most important operation to be performed while casting. For more detail please read my post “Concrete compaction”.
Concrete curing will allow the concrete expressing its best. Please read my post “Concrete curing”.
Even the cleaning of the building site has its own influence on the final result. You can read more in my post “Concrete & cleaning”.