The amount of cement per cube of concrete: calculate the

One of the first questions that a novice master is interested in when planning construction work is the amount of cement per 1 meter.³ concrete. And this is quite understandable: when pouring a foundation or monolithic walls, it is cement that is the most expensive component, and therefore it is often necessary to buy it "butt".

However, as in many other situations, you will not find a universal answer to this question. Proportions and ratios depend on many factors, and therefore for each situation they need to be made separately.

Component ratios в бетоне

Description of the composition

Kneading the mortar with our own hands, we need to prepare all the components.

Namely:

• Binder - Portland cement, slag portland cement, pozzolanic compound, etc. The first option is the most common, because it is quite affordable and has a fairly affordable price. The strength of the material, which is obtained after hardening of the cement as a result of reaction with water, is determined by such an indicator as a brand (denoted by the index M with a digital value).

• Fillers - sand and gravel. They provide the design of the desired volume, increase the coherence and strength of the material. The ratio of binder and filler largely determines the mechanical properties of the structure.

Note! In some cases, not solid material is taken for filling, but vice versa - porous substances like expanded clay, pumice or perlite. Here, the filler is not responsible for mechanical, but for thermal insulation functions.

• Water - very important component. The fact is that in order to harden the cement, it must necessarily be hydrated, therefore, a sufficient amount of liquid must be added to the concrete solution. Water quality is also very important: impurities and pollution reduce the strength of concrete, and high salinity can cause salt streaks on the surface.

• In addition to all of the above, when pouring concrete, the instruction recommends the use of modifying additives.. Their functionality is very diverse: some increase plasticity, others speed up hardening, others prevent water from freezing and make it possible to lay the solution at negative temperatures.

Competently combining all the components, we will be able to get a quality solution, from which then a construction stone will come out with good performance properties.

Factors affecting the proportion of cement

If we have dealt with general questions, it’s time to go specifically to cement. Before calculating its required volume, you need to figure out what affects the proportion of binder in the solution.

The key factors in this case are as follows:

• Firstly, the calculation of the amount of cement per 1 cubic meter of concrete is carried out depending on the required class of finished material. In other words, the stronger the concrete we need, the more binder (and, accordingly, less aggregate) we need.

• Во-вторых, важную роль играет марка цемента. Здесь связь тоже очевидна: можно или положить определенный объем высокомарочного состава, или несколько больше низкомарочного. В частом строительстве обычно поступают таким образом: при замене цемента M400 маркой М300 массовую долю материала увеличивают на 20-25% и наоборот.

However, in some situations the consumption of the binder can be reduced:

• First, various additives, primarily hardeners and plasticizers, contribute to this. To date, their range is very extensive, because the calculations with the use of correction factors need to be performed for each additive separately, guided by the manufacturer's instructions.

Note! Due to the use of additives, the price of the finished solution can be significantly reduced, so you should not neglect them.

• Secondly, during thermal processing of building blocks, as well as during heating of the poured foundation with wires or heat guns, strength is more effective. Thanks to this, we are able to reduce the proportion of cement and significantly save.

Actually, the theoretical calculations end there. For further work, reference materials should be used, some of which will be given in the next section.

Examples of proportions for commonly used concretes

When preparing a solution for pouring concrete, we usually try to take precisely measured portions of the components (cement and sand - up to a kilogram, rubble - up to five kilograms). Here it is best to focus on the previously calculated ratios, which we present in the table below:

Note! In drawing up the proportion, the shelf life of the cement should also be analyzed. The thing is that with time, the grade of the compound is reduced, and the old binder needs to be taken slightly more than the freshly prepared one.

In addition to tables from regulatory documents, it is convenient to use special programs, calculators, when calculating the proportions of concrete. To obtain correct results, it is important to know the basic parameters of the materials used (bulk and specific gravity of rubble, sand and a binder), as well as at least approximately imagine the required volume of the solution.

Conclusion

Having correctly selected the amount of cement per 1 cube of concrete, we will be able to produce high-quality material with the required mechanical properties. It is impossible to make a mistake here: the over-expenditure of the binder leads to a rise in the cost of construction, and its lack leads to the fact that the aggregate is not sufficiently secured together. As a result, the reliability of the erected structure is reduced, and its service life is reduced by several times.

You can study this issue in more detail by viewing the video in this article.