ELAZIG GUNISIGI NEWSPAPER - July 2010
HOW TO EXTINGUISH A CONCRETE FIRE?
Since the establishment of the Republic of Turkey, one of the biggest problems faced by the state has been urban development and housing. Financial and technical limitations have been among the greatest obstacles to urbanization. While these obstacles have been overcome and urban development has begun, significant deficiencies, either due to unawareness or negligence, have started to grow alongside. The consequences of these deficiencies have been felt during many earthquakes, and we have all paid the price together. As much as we can, we continue to express the shortcomings and potential solutions for both existing buildings and newly constructed ones.
It’s summer, and especially during daytime hours, unusual weather conditions prevail in our province that affect concrete pouring and curing. The most important building material impacted by these conditions is concrete. Regardless of how well concrete is manufactured, if the proper curing conditions are not met, its actual strength will never match the expected strength! Just as humans require more water in hot weather, concrete also needs more watering to reach the desired strength. Once again, I feel it is useful (though I am aware this won’t be the last time) to clearly reiterate the necessary information in order to address the significant deficiencies in our province.
Does Concrete Need to Be Cured (Watered)?
Concrete consists of water, cement, sand, and gravel. Water and cement react with each other, and this reaction releases heat. If the heat within the concrete is not reduced, it will cause the water in the concrete to evaporate, leading to low concrete strength. To allow the concrete to cool and achieve the desired strength, it must be cured (watered) after it sets and hardens.
Does Concrete Need to Be Cured in Every Season?
Once the appropriate conditions for pouring concrete are established and the concrete is poured, curing is essential. In hot weather, curing should be extended for a longer period.
What Time of Day Should Concrete Be Watered?
Concrete samples are kept in curing tanks for 24 hours and for 28 days, so there is no specific time limit for watering concrete. However, watering during midday is not ideal because much of the water will evaporate. Additionally, working with molds becomes difficult in a wet environment, so it is recommended to water the concrete in the morning and evening. This does not mean that watering should be avoided at noon.
How Much Water Should Be Used for Curing in Construction?
Concrete should not be watered like grass or plants. The amount of water should be determined based on the need to reduce the temperature of the concrete without allowing water to evaporate from the surface. Curing should be done by qualified personnel, or the workers should be trained and informed about the process.
Is It Sufficient to Water Only the Slab?
One of the most common mistakes is watering only the slab. Like the slab, columns, walls, and beams are also made of concrete and have the same properties. Therefore, the newly poured slab, both on the top and bottom, must be watered until the concrete temperature is lowered. (Sadly, I can confirm that this practice is almost never implemented in Elazığ. No curing is done on the underside of the slab, i.e., in the intermediate floors.)
How Long Should the Curing Process Continue?
The standards specify minimum curing times. However, many factors such as ambient temperature, cement dosage, type of structure, cement type, wind, and humidity can affect these times. Therefore, curing should be applied in a way that minimizes the differences between the actual structure and the samples. For residential buildings, the recommended curing duration for each floor is no less than 21 days.
What Happens If Curing Is Not Done During Construction?
Concrete strength decreases by at least 40%. This results in both financial and moral damage. It also means a loss of national wealth.
Which Structural Elements Should Be Cured in the Rough Construction Stage?
Curing starts with the foundation slab concrete and continues with each concrete element on every floor. Additionally, all walls, whether rough or finished, and both plaster and mortar layers must undergo curing. This means that curing should continue until the rough construction is completed. Any material containing cement must be watered.
What May Seem Like a Detail or Something Unimportant Could Be the Beginning of the End. Let's Overcome the Disease of Indifference and Pay Attention...
The issue of concrete curing is essential for ensuring the durability and safety of buildings, and it must be given the attention it deserves throughout the entire construction process.