One of the significant indicators of concrete quality is its strength. If you look at state standards, then you can find compression conditions in them. According to them, the strength can be equal to the limit of M50-800. Cement brands up to M-500 are among the most frequently used ones. Many professional builders and private developers take into account the curing schedule of the material. About it and will be discussed below.
For you, this information may also be useful, because from it you can find out how long after mixing the solution you can begin further work. This is due to the fact that the manipulation of the construction may involve the loading of concrete structures. Most often in conjunction with this, we are talking about foundations, which must be sustained for 28 days before the start of walling.
Scheduled strength
The set of concrete strength depending on the temperature is determined by the schedule, which is a time interval. In the process, the solution gains operational properties, after which it is possible to carry out the formation of the finish layer. The set strength chart is the time it takes concrete to reach the desired strength value. If normal conditions are maintained, then the composition will mature in 28 days.
Within 5 days, the fastest hardening can be observed. After this time, the material reaches 70 percent strength. Subsequent work should be continued only after 28 days, because only then will the material reach a 100 percent strength level.
Hardening and curing of concrete occur in different ways for each specific case. In order to determine the timing, tests of samples are carried out. In warm time, in a monolithic house-building, some operations are carried out to obtain the composition of optimal properties. For example, the material is aged in the formwork, it is left to ripen after removing the fences. The set of concrete strength depending on the temperature will occur over a different period of time. This is also due to the fact that events can be held in the cold season. In this case, to achieve brand strength, it is necessary to provide heating of the material and waterproofing of concrete. This is due to the fact that a decrease in temperature slows down the polymerization process.
Speedup Tips
In order to accelerate the set of strength and reduce the exposure time of the material, it is necessary to use sand concrete, in which the low ratio of water to cement. If this ratio looks like 1 to 4, then the terms will be compressed in half. In order to achieve this result, the composition should be supplemented with plasticizers. It is possible to reduce the ripening time of the material by artificial means, increasing the temperature.
Dependence of the level of strength gain on the temperature indicators of the material
The set of concrete strength depending on the temperature of the material will occur in different ways. As an example, consider concrete grades ranging from M-200 to M-300, which were shut on Portland cement with markings ranging from M-400 to M-500. In a day, the material will reach three percent compressive strength if its temperature is -3 ° C. Under the conditions that the mixture will have a temperature of +30 ° C, the strength per day will be 35%.
In three days, the strength will reach 8% if the temperature of the material is -3 ° C. 60% of the strength can be achieved at +30 ° C temperature over the same period of time. If the temperature of the material is +5 ° C for 28 days, then the strength of the material will be 77%. One hundred percent strength can be achieved in 14 days if the temperature of the material is +30 ° C.
Process control
The set of concrete strength depending on temperature was highlighted above. However, it is important to monitor the process during the first week. Activities aimed at providing conditions for aging are expressed in:
- electric heating;
- moisturizing;
- covering with moisture protective and heat insulating materials;
- heated by heat guns.
It will be necessary to pay attention to wetting the surface. One week after the composition is developed, the structure can be loaded, this is true if the air temperature is 25-30 ° C.
Additionally, the stages of curing
The setting of pouring concrete takes place in the first day after its preparation. It is imperative that a private builder needs to know what is the dependence of the set of concrete strength on air temperature. For example, in warm weather, when the temperature outside the window is within 20 ° C, setting will occur within an hour. The process will begin in a couple of hours, the countdown must be carried out after connecting the components, and will end in 3.
Cool time
When cooling, the beginning and end of the setting are shifted. It will be enough more than a day to set. If the temperature is at zero, then the process will begin at least 6 hours after mixing. Under such conditions, it lasts up to 20 hours, the countdown begins after the solution is in the formwork. On a hot day, time decreases. This indicates that sometimes it takes just 10 minutes to set.
Decrease in viscosity
You must have studied the process of setting concrete strength depending on temperature. It is important to know about viscosity reduction. In the first stage, the mixture will retain mobility. During this time, the material can be mechanically impacted, while the structure can still be shaped. It is possible to extend the setting stage by thixotropy, which will contribute to a decrease in viscosity during mechanical action.
A great example is a solution mixed in a concrete mixer. During this period, the solution will remain longer in the first stage. But it must be borne in mind that many processes cause irreversible changes in the solution, which can negatively affect the quality of hardened concrete. For example, “welding” in the summer period occurs rather quickly.
Hardening stage
The set of concrete strength, the timeline of which is described in the article, begins after setting. This process is still not over in a few years. But after 4 weeks you can determine the brand of concrete. The strength of the material will be gained at different speeds. This process will proceed as intensively as possible in the first 7 days. In the first three days under normal conditions, the strength will reach 30% of the brand value. During the first two weeks, the solution will reach 70% of the strength of the specified value. After 3 months, this parameter will increase by 20%, after the process will slow down, but will not stop. After 3 years, the indicator may increase by 2 times.
Additionally, the effect of ambient temperature on material hardening
The set of concrete strength, features, the schedule of which is described in the article, depends on temperature. The colder, the slower the strength will increase. At low temperatures, the process stops altogether, as the water freezes, and yet it provides hydration of the cement. As the temperature rises, dialing continues. But with a decrease, this process will stop again. If modifiers are present in the composition, the hardening time is reduced, while the temperature at which the process stops is reduced.
On sale you can find high-speed compounds that have the ability to give concrete brand strength after 2 weeks. Since warming will help to reduce the ripening of the material, it can be argued that at 40 ° C the brand value will be reached after 7 days. Therefore, pouring concrete should be carried out in hot weather. In winter, to ensure normal conditions, heating of the material will be required, and it will be problematic to carry out such work on your own, because special equipment will be required. In addition, heating the solution to 90 ° C and above is unacceptable.
Conclusion
The graph of the set of concrete strength, the conditions of solidification by you must be studied before starting work. Thus, according to the schedule, you can determine how much time can be taken to dismantle monolithic structures. The dismantling of the formwork can only be carried out after the strength of the material exceeds 50% of the brand value.
It should be borne in mind that if the bar drops below +10 ° C, then this value will not be reached 2 weeks after pouring. Under such conditions, you need to think about heating the solution. A safety standard is set at 50 percent strength. Then, how to proceed with further work is possible only after the brand value of the solution reaches 80%.