The concrete preparation solution includes cement, sand and crushed stone. However, the main component is a cement mixture. The strength index, as well as frost and moisture resistance, depends on its quality and quantity.
The quality of the concrete mix is also affected by the brand of cement: the higher it is, the less various impurities and additives are used in its manufacture. However, do not forget that buying each extra kg of cement can significantly increase the cost of construction work. Knowing the cost of cement per 1 cubic meter of concrete is a basic requirement even before the start of construction, and therefore you have to carefully perform calculations, determine the ratio and price of each necessary component. And that is why it is very important to properly observe the proportions, because the durability of the finished building depends on it.
What do you need to know to get the required volume of concrete?
Depending on the characteristics of the materials and production technology, a certain brand of concrete is obtained. There are special reference books that describe the content and ratio of components used to prepare the necessary solution.
To calculate the amount of cement in 1 m3 of concrete, usually take into account:
- grade and density, as well as the average setting time of portland cement;
- mobility and ductility, which depend on the amount of high-quality fillers;
- sand quality, as well as the type and fraction of crushed stone: the absence of impurities allows the use of materials without pre-screening and washing;
- the presence of plasticizers and hardeners helps to improve the quality of the material.
Calculation of the volume of cement for the required amount of cubic concrete
How to correctly calculate cement per cube of concrete and take into account all the nuances of a building structure? To calculate the consumption of cement per 1 m3 of mortar, you need to know its scope of application. Usually there is 240-320 kg of cement per cubic meter of concrete (depending on the brand of building material).
When choosing brands, keep in mind that the brand of cement should exceed the brand of the finished mortar. So, to get M200 concrete, you need to take the M400 cement brand, and to get the M400 brand, you need cement mixes with a strength of at least M500.
Important! The higher the marking of the components, the smaller the volume of cement required to prepare the concrete solution. A bag of better quality cement may be enough for a larger amount of work and vice versa. Just consider all these factors when buying building materials.
How much cement will you need for 1 m3 of M300 concrete?
Here is an example of calculating the number of components for the manufacture of 1 m 3 solution. Concrete products of the M300 brand are considered particularly reliable and durable. This solution is used to fill the foundation and floor, and to build walls made of bricks or panels.
To get one 300 cube of concrete, you need to use the following dry components in parts:
- cement M400 -1 part (366 kg);
- sand-2.8 parts (1025 kg);
- crushed stone or gravel-2.8 parts (1025 kg);
- water.
These calculations are made taking into account the friability of cement of 1500 kg/m3, which is typical for material packed in bags of 50 kg.
Water usually accounts for at least 20% of the total volume. It is not recommended to exceed or reduce its amount: if the concrete mass is too liquid, it will not be able to hold the binders; if it is too dense and thick, the mortar will crack as it dries.
How do I choose the right brand of concrete?
The question is quite simple, because the brand and class of material are specified in the project documentation for each construction object. In the event that the developer is a private individual and builds a house on his own, he himself should determine the brand of the warehouse, based on the features of the structure and the environment, the quality of the soil and other nuances that somehow affect the choice of building materials. The final cost of construction will depend on its calculations.
The choice of concrete grade depends on the object’s purpose:
- M100 is used for light reinforced concrete products (curbs, paving slabs);
- The M150 is used for laying paths and sidewalks, as well as constructing low fences;
- M200 is used for the construction of external and internal walls of buildings;
- M250 and M300 are used for filling foundations and floors, for the production of load-bearing structures and floors, stairs and supports;
- The M350 is suitable for the construction of support towers and pillars, columns, beams and for casting monolithic foundations.
The quality of concrete and the formation of its strength grade is affected by the presence of additives:
- modifiers are designed to increase the frost resistance and wear resistance of reinforced concrete products;
- plasticizers increase the mobility and waterproofness of concrete;
- antifreeze additives allow you to work at low temperatures (up to minus 20 degrees);
- accelerators increase the rate of setting of the mortar and provide the declared strength of concrete in the first day.
Consumption of the above-mentioned additives is carried out taking into account the recommendations of manufacturers. For the production of high-quality concrete, it is necessary to comply with the requirements of the tables indicated on the package. In case of violation of these instructions, a solution with completely unpredictable properties can be obtained.
What should I do if I bought the wrong brand of cement?
If at the stage of mixing the mortar it turns out that you ordered a cement mixture of the wrong strength grade that is needed, do not despair!
To prepare a mixture of low-grade cement, its volume should be increased by 15%, and sand will need to be added by 10% more. This pattern will help you calculate the required number of components and achieve the stated indicators. As a result, the concrete will get the proper strength grade.