In the process of construction, restoration or repair, we are constantly confronted with works in which a concrete mortar is used. But how to cook it? After all, you need not only to purchase the necessary materials in the right amount, but also to produce the correct batch, which implies, among other things, determining the optimal proportion of components.
What causes non-compliance with the proportions, it is known - cracks in the screed or in the base of the structure, the fragility of the masonry and the like "surprises".In order to avoid such troubles, it is first necessary to determine the following points:
firstly, for which solution is intended? For example, concrete mixes for pouring a tape "monolith" under the foundation and for bonding bricks, cellular blocks are prepared in different ways. In other words, what brand of concrete should be obtained in the end? Here you will need information on the strength of concrete grades.
second, what characteristics have the components used?
It is necessary to understand in detail the last point. What is considered?
For rubble( gravel)
Weight, pellet sizes, flakiness, contamination, humidity level.
For sand
Same( except flakiness) plus the presence of a variety of impurities.
For cement
Brand, setting time, production date.
Some indicative data on cement consumption can be given. But we need to understand that they only allow us to estimate approximately its quantity in the "cube" of the solution, since they are derived from the average values, without taking into account the specifics of the work:
Practical recommendations of
It is necessary to pay attention to the shelf life of the cement. Experts say that for half a year after manufacturing, it loses up to 30% of its qualities. Consequently, when using the "old" product, its share in the total mass should be increased so that the strength of the concrete is calculated.
For this reason, professionals recommend the use of "fresh" cement for construction, and products that have been stored for a while, used for restoration, repair( sealing joints, slots) or the construction of minor structures. And then, provided that in the future they will not be subject to significant stresses. The point is that for an astringent, released more than a month ago, it is difficult to determine the exact ratio with other components.
The lower the cement grade, the more it needs to be added when preparing the mixture.
For foundation pouring, experts advise you to follow such a ratio( measure-bag): 1( binder) + 3( sand) + 5( filler).Such a solution is considered universal.
To get the guaranteed strength of concrete, it is better to add 1 kg of cement to the mixture than not to report it.
