The construction of a building is an activity exclusively reserved for professionals. However, for small jobs like concrete earthworks, you can do it even without training. All you need is the information required to perform the correct dosages.
What are the main components of concrete?
To achieve concrete, several materials are generally involved. Each of them is necessary to have a good result.
- Cement, he plays a decisive role in the solidification of concrete. It is the binder which makes it possible to solidify all the other elements which intervene.
- The sand also called aggregate has the role of filling the spaces between the gravel. It gives a more compact texture to the structure.
- The water allows the hydration of the cement and facilitates the workability of the concrete to make installation easy.
- The gravel as for him is the main element which forms the skeleton. It can be smooth particles or crushed rock from quarries.
Each of these components is essential to have a good result. They are sometimes associated with others to have a more specific rendering, but these are optional.
What are the optional components for concrete?
To have special concretes that meet specific requirements, certain materials must be involved. iron, to give it tensile strength and thinners to obtain a more manageable mixture. Some use other adjuvants such as accelerators, retarders or the mass water repellents. Although they are very effective, they are not essential in all concrete work.
The main rule of concrete dosage
It is easy to obtain quality concrete for earthworks. The secret is found in the respect of the rule known as 1 2 3. The latter results in a suitable use of each element. It consists of a dosage of the components in the appropriate quantities. This is’a volume of cement, for two volumes of sand added to 3 volumes of gravel. To this mixture, we add a half volume of water to get the earthworks concrete. For other types, it will be another manipulation.
How to mix manually with a 35 kg bag of cement
To obtain homogeneous concrete by hand with a 35 kg bag of cement, you will need:
- 75 liters of sand which is equivalent to about 15 standard shovels
- 9 buckets of gravel or 20 round shovels
- 17.5 dm³ of water
It will be necessary to mix all the elements and make a crater in the product obtained to pour the water there.
Make 3 m³ of concrete with a concrete mixer
For such a quantity, it is necessary to use:
- 30 bags of cement of 35 kg
- 1600 liters of coarse sand 0/8
- 2090 gravel lite 8/20
This quantity will be divided into 30 equal batches to be introduced into a 130 L concrete mixer. If the capacity of the latter reaches 280 L, just 11 batches will have to be made.
At this stage, you have to mix the sand and cement in small piles to get a bigger one. Use the shovel to dig a crater in which you will pour the gravel and then the water. Using your instrument, stir everything to have a homogeneous mixture. In addition, you must have strength in your arms to use this technique. Otherwise, opt for a concrete mixer.