How do I make cement

Mixing concrete yourself is not a challenge - as long as you know the correct mixing ratios. These in turn depend on what is to be concreted. Will the concrete later only be exposed to mechanical loads or will it also have to withstand frost and chemical influences? In order to achieve a robust result, the ratio of the individual components must be optimally coordinated.

mixture

Concrete consists of three components: cement, water and the so-called aggregate. The surcharge is sand, gravel or grit.
The ratio between cement and aggregate is 1: 4. Concrete therefore consists of one part cement and four parts aggregate. Then there is the water. How much water is added, however, depends on the exposure class. This indicates how heavily and how the concrete will be loaded later. However, the amount of water can also be easily calculated.

Density and quantity

Concrete has an average density of 2.4 to 2.5 kg / dmĀ³ (kilograms per cubic decimeter). For a volume of one cubic meter, 2,400 to 2,500 kg of concrete are required. From this it is very easy to calculate the amount of cement required.

Concrete consists of one part cement and four parts aggregate and one fifth of cement. The total amount of concrete required is therefore only divided by five to get the amount of cement required. For one cubic meter this means:
  • 2400 kg / 5 = 480 kg
  • 2500 kg / 5 = 500 kg
For one Cubic meters of concretewill therefore 480 to 500 kg of cementneeded.

Of course, the calculation can also be carried out in the other direction in order to calculate how much concrete can be made from the existing cement. To do this, the amount of cement is simply multiplied by five. This results in the standard packaging size of 25 kg of cement:
  • 25 kg cement x 5 = 125 kg concrete

W / C value

The W / C value indicates how much water has to be added to the cement and the aggregate in order to obtain the most resistant result possible. The value depends on the stresses and environmental influences the concrete is to withstand later. The W / C value is in each of the following cases:

Mechanical wear
  • Very strong 0.40
  • Strong 0.45
  • Mediocre 0.55
frost
  • With high water saturation 0.50
  • With moderate water saturation 0.60
Chemical influences
  • Weak 0.60
  • Mediocre 0.50
  • Strong 0.45

Calculate ratios

In order to calculate the need for cement, aggregate and water, the necessary total amount in kilograms must first be calculated. To do this, the volume is first calculated, whereby length, width and height are multiplied with each other. For example, if a path one meter wide and ten meters long is to be provided with a ten centimeter thick layer of concrete, the required concrete volume is:
  • 1 meter (width) x 10 meters (length) = 10 square meters
  • 10 square meters x 0.1 meters (height or thickness of the concrete layer) = 1 cubic meter
Based on the average mass of 2,450 kg of concrete per cubic meter, 2,400 to 2,500 kg of concrete are required. This in turn results in a need for cement of:
  • 2,500 kg concrete / 5 = 500 kg cement (20 bags of 25 kg each)
For the surcharge, the total amount of concrete is multiplied by 4/5 or 0.8 or the difference between the total amount and concrete is used.
  • 2,500 kg concrete x 0.8 = 2,000 kg surcharge
  • 2,500 kg concrete - 500 kg cement = 2,000 kg surcharge
Finally, the required amount of water is calculated using the W / C value. For example, if the concrete is exposed to strong mechanical wear, the W / C value is 0.40. The ratio of cement and water is calculated by simple multiplication:
  • 500 kg cement x 0.40 W / C value = 200 liters of water
For the example given with an amount of 2,500 kilograms of concrete, 500 kg of cement, 2,000 kg of aggregate and 200 liters of water are required.

costs

For a standard packaging size of 25 kg of cement, costs of 3 to 6 euros should be expected. The above example requires 500 kg of cement. The costs for this are calculated as follows:
  • 500 kg total amount / 25 kg sack = 20 sacks of cement
  • 3 euros per sack x 20 sacks = 60 euros
  • 6 euros per sack x 20 sacks = 120 euros
The average costs can therefore be between 60 and 120 euroslie.
In addition, there are the costs for the respective surcharge. For concrete gravel, chippings and sand, depending on the size, you can expect 30 to 50 euros per ton, which results in a price of 60 to 100 euros for the calculation example.

So for the raw materials it should be with 120 to 220 eurosbe expected.
It should be ensured that the delivery is often higher than the price of cement and aggregate due to the high weights. This information is therefore not the total price.