Every builder knows that before the construction of any structure, a very important stage is the preparation of the foundation. Whether it is a strip foundation or a monolithic slab, even a blind area or a base for sidewalk tiles, it is important to tamp the soil so that later under our structure it does not start condense.
In 90% of cases, we observe that the preparation of the base proceeds as follows: a trench or foundation pit is dug to the required depth, after which is filled with either crushed stone or sand, and then the bulk material is leveled and rammed (most often by mechanized way). This is not bad, but there is a method that is much more effective than just tamped crushed stone bedding. In addition, it comes out even cheaper and gets done even faster ...
And not only will it come out to us at no extra cost, but we will also get an incredibly rigid base, which is simply impossible to achieve with ordinary bedding or a pillow of sand / crushed stone. This compaction is done using the road foundation preparation method.
When I said this to my friend before the construction, his eyes widened and he asked "Where can I get a skating rink? You also need to lower it into the pit!? "
Of course not, a roller is needed for large volumes, and we will only need a conventional vibratory rammer ...
So...
You need to purchase large crushed stone of fraction 40-70 (the diameter of individual stones is from 4 to 7 cm). Further, after excavation, the crushed stone crumbles in one layer to a height of 5-10 cm from the ground. One layer is important!
Thus, for a foundation slab with dimensions of 10x10 m, you need only 7-10 cubic meters of crushed stone, and this is no more than 15 tons or one KamAZ!
After leveling, crushed stone is rammed into the ground:
Crushed stone very strongly penetrates the soil into the depth only when it is poured into one layer, since the impact of the rammer falls directly on the stone, which cuts into the base. This method is called - splitting (from the word wedge).
It is this method of compaction of the base that is used in road and airfield construction. Only during the construction of roads, large crushed stone is wedged into small (and so at least 3 layers) in decreasing fractions - smaller fractions wedge larger ones. The base becomes even and incredibly rigid, withstanding enormous dynamic loads, and it is already possible to lay asphalt or asphalt concrete on it.
In our case (for foundations), one layer of crushed stone of fraction 40-70 is sufficient. And for the blind area and medium crushed stone (fraction 20-40) is enough, or in extreme cases - 5-20, as I did last year ...
Why is it better this way?
The soil is subjected to point compaction (under each separate stone, the soil is crushed locally) and such a base capable of carrying much greater static and dynamic loads from a higher structure without shrinkage and deformations.
I repeat that this method is much more effective than various beddings and pillows. And if you wish, you can wedge large crushed stone with small ones, yet more - not less, the owner is a master!
And that's all, thanks for your time!
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