WHAT IS CONCRETE?
‘Concrete’ is a building material obtained by mixing aggregates, cement, water, chemical admixtures and, when necessary, some building materials complying with production standards together.
WHAT IS FRESH CONCRETE?
We may call the easily mixable, movable, placeable, compactible and burnishable form of concrete remaining soft and formable for a while once concrete materials have been mixed together “fresh concrete”.
PLACEMENT OF CONCRETE AND WHAT SHOULD BE DONE BEFORE PLACEMENT?
Placement method and casting time should be predetermined.
Before casting unreinforced and ground concrete, the section to which it is to be applied should be humidified and compacted, thus making it ready for casting.
Formwork should be made ready to use by applying clean, durable and standard form oil.
WHAT SHOULD BE PAID ATTENTION IN FINISHING CONCRETE SURFACE OPERATION?
In case of slap concretes, surface finishing operations are predominantly carried out by means of steel or wooden floating rules and trowels. And in cases requiring trimming, bevelling and aluming operations, border finishing operations should be first carried out. A bristle broom may be applied in a certain direction in order to provide the required roughness after floating rule and trowel operation.
WHAT IS MAINTENANCE OF CONCRETE?
The process of keeping the concrete at proper humidity and temperature conditions for a sufficient period of time immediately after the processes of placing, compacting and floating the concrete so that any properties expected of the concrete may develop is called maintenance. Objective of the maintenance process is to fill the capillary pores initially filled with water with hydration products as much as possible.
WHAT IS A COLD WEATHER CONDITION?
TS 1248 ‘Concrete making, casting and maintaining rules’ standard considers a condition in which the average air temperature is lower than 5°C for three consecutive days to be ‘cold weather’. Daily average air temperature is the average of the lowest and highest air temperature recorded during the period of time elapsing from one midnight to the next midnight.
WHAT IS CHEMICAL ADMIXTURE?
They are organic and inorganic substances other than cement, aggregate and water added at a rate of maximum 5% of the cement dosage. They are chemical substances applied by adding to the concrete mixing water for such purposes as improving the workability of fresh concrete, changing setting times, affecting the properties of hardened concrete and improving its strength.
WHAT IS A WARM WEATHER CONDITION?
TS 1248 ‘Concrete making, casting and maintaining rules’ standard defines a weather condition in which air temperature is above 30°C for three consecutive days as ‘warm weather’.
WHAT DOES ADDITIONAL WATER CAUSE AT A CONSTRUCTION YARD?
Addition of water to the concrete for any reason whatsoever by intervening the mix design at the concrete casting site causes the water-cement ratio which is determined by concrete classes and which is the main source of strength to reduce and thereby fail to provide the strength as required by the concrete class. It further prevents the chemical admixture applied at the determined percentage so that workability of concrete may be at optimum level from working and the water delivered so that the concrete may be worked makes an adverse effect as a result of segregation, thus making the concrete unworkable.