Being filled into a space bounded by formwork and equipped with metal frame from steel reinforcement, concrete grabbed over the next few hours. Full drying and hardening occurs for much larger time.
Before starting construction, the masters pay attention to the causes, directly or indirectly affecting the pouring of concrete. We are talking about speed, the duration of the complete solidification of the concrete composition, in which the carrying metal frame is immersed, preventing cracking and spreading in different sides of the parts of the bombardment structures.
First of all, the climate of the hardening is influenced by the climate, the weather of the day of bookmarks and the days of the subsequent set by the filled building materials of the stated hardness and strength. In the summer at a 40-degree heat for 2 days he will completely dry. But its strength will not reach the stated parameters. In the cold season, when the temperature is plus (several degrees of heat), due to a slowdown in 10 or more times, the speed of moisture evaporation period of complete drying of concrete is stretched for two weeks and more.
In the instructions for the preparation of the concrete composition of any brand, it is said that only for the month he gains his real strength. Hardening at relatively normal air temperature may and should occur in a month.
If on the street heat, and the water evaporates quickly, then the concrete base, filled 6 hours ago, weanly water every hour.
Concrete base layout density directly affects the final strength of the flooded and hardened construct soon. The greater the density of the concrete material, the slower he will give moisture and the better grabbing. Industrial molding of reinforced concrete is not without vibratory. At home, it is possible to compact concrete with the help of the same shovel, which he was satisfied.
If concretease went into the case, the pin (settling with a bayonet shovel) is also necessary – concrete and only increases the feed rate, but does not eliminate the deadlocking of the concrete mix. If concrete or concrete screed is completely sealed, then such a material is more difficult to drunkenness, for example, to install beams under wooden flooring.
The composition of concrete also plays the last role in the speed of solidification of the concrete mix. For example, clamzite (ceramzite concrete) or slag (slag concrete) takes on a part of the moisture and not quite willingly and quickly returns it back when concrete grip.
If there is gravel in the case, the water will noticeably leave the hardening concrete.
To slow down the loss of water, only a flooded design is covered with a thin layer of waterproofing – in this case it may be polyethylene from foam blocks, which they were closed during transportation. To reduce the velocity of water evaporation into concrete, we can mix a weak soap solution, but soap stretches the process of setting concrete by 1.5-2 times, which will noticeably affect the strength of the whole structure.
The prepared solution of concrete is a semi-liquid or liquid mixture, except for the presence of gravel in it, which is solid material. Concrete consists of rubble, cement, sand (you can career seeded) and water. Cement – Mineral, which includes a hardened reagent – calcium silicate. Cement, as is known, reacts with water to form a stony mass. In essence, cementops and concrete – artificial stone.
Solidification of concrete two-stage. During the first couple of hours, the concrete dries and grabbed partly, which gives an incentive after cooking concrete as soon as possible to pour it into a prepared formwork compartment. Reacting with water, cement turns into calcium hydroxide. From its quantity and depends the final hardness of concrete composition. The formation of calcium-containing crystals leads to an increase in the temperature of the hardening concrete.
Different brands of concrete, time grasping also varies. So, the M200 brand concrete has a grappling time equal to 3.5 h. Since the completion of mixing the main ingredients. After the initial frost, he dries during the week. Final solidification ends only on the 29th day. In the final monolith, the solution will turn at a temperature of + 15 … 20 degrees Celsius. For the south of Russia, this is the temperature of the off-season – the best conditions for the construction of concrete structures. Humidity (relative) should not exceed 75%. The best months for laying concrete are May and September.
Falling the foundation in the summer, the master in the master is a great risk of running into premature drying of concrete and it is necessary to irrigate regularly – at least once per hour. Grappling in an hour is unacceptable – the design with a large probability may not dial the stated strength. The foundation becomes extremely fragile, cracking, significant pieces of it can fall off.
If the water is missing for timely and multiple moisturizing concrete, then the composition, half or completely climbing, without waiting until all the water evaporates, tightly covered with a film.
However, the more cement in concrete, the sooner it will grab. So, The composition of the M300 may be grabbed in 2.5-3 hours, M400 – in 2-2.5 hours, M500 – in 1.5-2 hours. The opilk concrete collapsing for about the same time as any of the concrete similar to it, in which the ratio of sand and cement is similar to any of the above-mentioned brands. It should be remembered that sawdust makes their negative impact on the parameters of strength and reliability and increase the time of setting to 4 hours and more. The composition M200 will fully gain strength in two weeks, M400 – for one.
The setting speed depends not only on the brand of concrete, but also from the design and depth of the lower edge of the foundation. The wider the ribbon foundation and the further it is bueled, the longer it dries. This is unacceptable in conditions where land plots in bad weather are often flooded, as they are located in the lowland.
How to speed up hardening?
The fastest way to make concrete dry as soon as possible – call the driver on concrete and whose concrete Specials are mixed. Supplier companies in their own test bureaus mix patterns of finished concrete with characteristics differing in different batches. Concretease will bring the required amount of concrete at the address specified by the client – at the same time, concrete will not have time to frozen. Pouring works are made over the next hour – to accelerate the case, a concrete pump suitable for the foundation is used.
To speed up the solidification of concrete in cold weather, so-called thermomats are attached to the walls of the formwork. They highlight heat, concrete is heated to room temperature and freezes faster. This requires an electrical connection. The method is indispensable in the conditions of the Far North, where there is no warm summer, and it is necessary to build.
When solidification of concrete composition, industrial additives and powder additives are used. They are added strictly at the stage of mixing dry composition with water, while planting gravel. Such acceleration helps to save on cement costs. Accelerated solidification is obtained using superplasticizers. Plasticizing additives increase the elasticity and fluidity of the solution, the fill uniformity (without precipitation of cement clad at the bottom).
Choosing an accelerator, pay attention to the activity of the substance. It should increase the waterproof of concrete and frost resistance. Incorrectly selected enhancers (frosted accelerators) lead to the fact that the reinforcement can significantly rust – right in concrete. That this does not happen and the structure did not fall on you and your guests, apply only branded, highly efficient additives and additives that do not violate neither the composition nor the technology of laying and curing the composition.