How many cubes are in a bag of cement - calculation and volume tables

It is not worth buying excess cement. When stored for a long time, even in a dry room, it loses its strength. In a year, it will be 50% of the nominal. That is why when purchasing it is worth knowing how much binder is required. But there can be problems. The proportions for concrete mortar are often given in volumetric fractions, and cement is sold by weight with packing in bags. The calculations may require the amount of cement in the bag. You can use the average and calculate approximately.

Cement bag volume

In general, the question of how much cement is contained in the bag is not so easy to answer. Let's start with the fact that the packaging is in bags of 25 kg, 40 kg and 50 kg. So we need to clarify the mass. The second point is that cement is different. With and without additives. And additives are also different and different types differ in density. This means that the same weight takes up a different volume.

The weight of the cement bag can be 25 kg, 40 kg and 50 kg

There is one more thing. The density of any cement changes over time. Immediately after production, when it is poured into bags, the density is lowest. While the ground powder is poured, its particles are charged and capture air molecules. Therefore, freshly poured it weighs less. During transportation and storage, the charge decreases, part of the air evaporates, and the density increases. So after a month, more weight is placed in the same volume. Moreover, after about a year of storage, the difference with the bulk density is significant - up to 35% of the initial value.

In the calculations, an average figure is taken, which is called the specific density. For each type of cement, it has its own and in calculations when determining the amount of required material, you can build on it.

Calculation method

Specific gravity of cement is the mass of one cubic meter. For Portland cement, for example, it is 1300 kg / m³. To determine the volume of cement in a 50 kg bag, you need to solve a simple proportion:

How to calculate the volume of cement in a bag

We found what percentage of one cubic meter is contained in one 50 kg bag of Portland cement. This is 3.85%. This means that this container contains 0.0385 m³ (we just "take a percentage" of a cubic meter).

Pivot table

For a bag of 25 kilograms, you can not count, but divide the resulting figure by two. One 25 kg bag of Portland cement contains 0.019 m³. For a 40 kg bag, you will have to re-calculate everything. It turns out 0.031 m³. Similar calculations must be done for all brands of cement with different densities. We did this and tabulated the data.

The volume of cement in a bag: a table for different containers and different brands of binder

Average values ​​are calculated in the table. If you know exactly the cube weight of your material (it can be indicated on the bag or you can weigh and calculate), it is better to recalculate. The difference is unlikely to be big, but still. How to calculate? Take a liter container, put it on the scales and weigh. Add cement - do not shake, do not compact. Just pour and weigh, and then subtract the weight of the container. You will find how much the kilogram of cement you bought weighs. Then multiply by 1000 (one thousand liters in one cube) and get the exact (almost) density of your material. Further in the calculations, you can use it.

How much concrete will make a bag of cement

Often proportions are given in volume fractions and therefore it is useful to know how much concrete can be made from one bag of cement when calculating. But we need to talk about a specific brand and about a specific concrete solution. The proportions are different and first you need to decide on this. The difference is significant, as can be seen from the following table.

How much concrete will be obtained from 10 liters of cement

For each binder and each brand, you will again have to count separately.For each concrete, the approximate cement consumption for the manufacture of one cube of mortar is known. Based on these data, you can calculate how much mortar can be obtained from a kilogram of cement. Further, it is easy to find out the amount of concrete that can be obtained from a bag of cement.

Consumption of binder by concrete grade

For example, per cube concrete grade М300 there are 350 kilograms of M400 cement. That is, from one kilogram, 1 m³ / 350 kg = 0.0028 m³ is obtained. To find out how much it turns out concrete grade M400 from a bag of 50 kg, multiply by 50. We get 0.14 m³. As you can see, the calculations are straightforward.

To fix the information, let's count for solution M200 and the same Portland cement M400. It needs 250 kg for this type of concrete. Then, from a kilogram, 1 cubic meter / 250 kg = 0.004 cubic meters is obtained. Then from 50 kg it will turn out: 0.004 * 50 = 0.2 cube, from 40 kg - 0.004 * 40 = 0.16 cube.