In light of the loads they must support, patios and driveways must be supported by sufficiently stable and robust foundations. This is why it is strongly recommended to pour a concrete slab on which your paving will then be laid. The concrete slab will itself be poured over a layer of crushed stone or rubble to ensure its stability and enable natural water drainage. On normal ground, a thickness of 5cm will be sufficient. However, if the ground is loose or if the paved area will have to support heavy loads (trucks), you will need to increase the thickness of the concrete slab or reinforce it with a welded steel frame. To avoid cracks in the concrete, it is important to include expansion joints when surfaces are greater than 30m².
Use concrete that contains one part cement to 3 parts aggregates; a concrete mixer will of course be needed if the surface is extensive. Once the concrete is dry (48 hours), you just need to lay the paving stones on a thin layer of cement mortar. It is recommended to add 20% of pozzolana in the fixing mortar to give it better elasticity and avoid the formation of cracks which risk compromising the durability of the paving. Another technique consists in laying a thin layer of sand between the concrete and the fixing mortar. A precaution to remember: wet the stones generously before laying them on the mortar, otherwise, the stone will come unstuck after a certain amount of time.
Sedimentary rocks are the result of the accumulation and compacting of mineral debris (i.e. other stones), organic debris (animal remains and vegetation, fossils), or chemical precipitation.
They are exogenous rocks, i.e. rocks are formed on the surface of the Earth. Sedimentary rocks are present on 75% of the surface of the Earth's continents, but when considering its crust as a whole (from the surface to a depth of 22 miles (35 km)), they only represent 5% of its total volume.
The main sedimentary rocks are:
Mont du moulin 30750 Lanuejols FRANCE.