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How to install gravel grids ECCOgravel?

4/30/2021

How to install gravel grids ECCOgravel?

The article below discusses the best way to install ECCOgravel gravel grids. This process can be summarized in 9 steps.

  1. Choice of slab height
  2. Choice of gravel
  3. Foundation requirements
  4. Removal of soil
  5. Placing the foundation box
  6. Applying a levelling layer
  7. Installation of the ECCOgravel grids
  8. Installation of the gravel layer
  9. Inspection and levelling

Gravel pavements are "in", but they have one big disadvantage. If they are frequently walked on or driven over, the gravel may start to shift. The comfort of the gravel paving can suffer greatly from this.

Installation of ECCOgravel grids

The installation of your ECCOgravel gravel grids is quick and easy. Before you start, determine exactly which type of slab you need and choose the correct foundation depth.

How to choose the right slab height

You can choose between a 3 cm or 4 cm high slab. The ECCOgravel 3 cm and 4 cm slabs have similar characteristics (wring load resistance, pressure resistance, flexibility, ...). However, the load distribution (of cars, ...) towards the foundation is better with the 4-cm grid than with the 3 cm one. We can explain this in simple terms using the example below.

Example:

1. You put a sheet of paper on your hand and hit it with a hammer.

2. You place a telephone book on your hand and hit it with a hammer.

Conclusion: the distribution of force is better in the second case. If we apply the same to ECCOgravel, we may conclude that the foundation will be less stressed when the slab is thicker. Can the ECCOgravel 30 grid never be used in car applications? Yes, on condition that the foundation is very strong. The extra costs for this additional reinforcement do not always outweigh the savings on a thinner grid. 

What type of gravel do I use in gravel grids

Size

It is advisable to use gravel types whose minimum fraction is greater than 4 mm. Finer fractions can stick to the shoes or get stuck between the profiles on the tires of the vehicle. To achieve optimum compaction in the honeycomb, we recommend limiting the maximum diameter of the gravel to 16 mm.

- Application without wagon: ideally 4 mm to 8 mm

- Application with wagon: ideally 8 to 10 mm up to 16 mm

Shape

First of all, round gravel as we know it is called pebble, broken gravel on the other hand remains gravel. Pebble is more pleasant for terraces and garden paths, gravel on the other hand has the advantage that the top layer (this is the layer on top of the honeycomb structure to make the structure invisible) will shift less easily. Gravel is therefore recommended in places where vehicles will drive on the pavement.

Hardness

Hard gravel types will crumble less easily under moving loads and will turn green less quickly because they retain less water (low porosity). A soft rock -with high porosity- on the other hand, pulverizes easily and dissolves in time. Consequently, the soft rock will eventually become permeable to water, leading to the formation of puddles and ruts. Moreover, it will turn green on non-sunny sides. Finally, the gravel of soft stones will cause dust to form in the summer and stick to the shoes in the winter.

Colour

Gravel or shingle is a natural stone and retains its color even after a long time.

What requirements must the foundations meet?

No frost-free depth required

Due to the flexibility of the slab and because the gravel is not bound, freezing has no effect on the ECCOgravel pavement. When designing foundations for asphalt and concrete paving slabs, it is always necessary to ensure that no water remains in the zone where frost can occur in the foundation. In the event of frost, this could cause the asphalt or concrete pavement to freeze. Therefore, the foundation depth for such materials is so extensive.

The depth of the foundation with ECCOgravel is therefore only determined by the loads the paving will have to endure.

No slope required

In contrast to concrete paving, ECCOgravel does not require a minimum slope. Even in case of very heavy rainfall, the buffer capacity will be sufficient to process the rainwater.

A small calculation: The maximum 20-year recurring rainfall intensity in Belgium is 270 l/s/ha. For 10 minutes, this corresponds to 16.2 l/m2. The rainwater will immediately seep into the hollow spaces of the gravel and the underlying foundations. This limits the risk of losing the functionality of the pavement due to water staying on the pavement.

A gravel layer of 5 cm can already hold up to 10 liters of water. It goes without saying that a minimal gravel foundation will take care of the rest. 

Installing gravel grids in 6 steps.

1.         Removal of the topsoil

Of course, you must start by removing the topsoil, for which the necessary digging must be done. These should extend 2 cm above the level of the top of the slab. 

2.         Placing the foundation box

Next, the foundation box is placed at a depth of at least 25 cm. For ideal placement of the gravel grids of ECCOgravel, one may work in layers of 20 cm maximum and compact with a vibrating plate. The foundation pit can be made of limestone rubble, porphyry rubble or broken concrete rubble (grading: 0-32 mm or 0-40 mm). We do not recommend using brick rubble, as this will pulverize in time. 

3.         Applying the levelling layer

The levelling layer is then applied in fine gravel, which must be compacted and levelled for optimum results. The depth of the levelling layer in applications with vehicles is 5 cm, applications without vehicles ideally 15 cm. The levelling layer can be made with limestone or porphyry (grain size: 2-4 mm, 1-3 mm or 0-4 mm) or with sieve sand. 

4.         Installation of the ECCOgravel grids

Finally, the ECCOgravel grids are laid with overlapping geotextile, which can best be cut with a grinding wheel. Then lay the grids in a semi-stone bond. 

5.         Laying the gravel layer

The last step is to lay the gravel, driving loads on the unfilled gravel grids is not recommended. Levelling is done with a shovel, brush, rake and squeegee do not compact the gravel. Leave the gravel 1 to 2 cm (1 cm for finer gravel and 2 cm for coarser gravel) above the grids. Due to natural compaction, the gravel will sink a little further. In time, there should be just enough gravel to make the ECCOgravel grid invisible. 

6.         Inspection and levelling

A few weeks after the first use, the area should be inspected and levelled. Add gravel where necessary, sagging will no longer occur!

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