What is heavy traffic for a gravel pavement?

By heavy traffic we mean applications where more than just the occasional passenger car drives over it. Think of car parks with daily turnover, business premises where vans load and unload, fire access roads that must remain accessible to the fire brigade, and driveways that a truck regularly uses.

Where does ECCOgravel fit in – and where doesn’t it?

ECCOgravel is ideal for car parks, fire access roads, industrial sites and driveways. The paving, when laid on a solid base, can withstand occasional heavy traffic, such as a lorry coming to deliver. Two situations should be avoided:

  • Heavy and fast-moving traffic

    Zones that are used intensively and at speeds faster than 10 km/h are best constructed in bound material. For the parking bays, use ECCOgravel.

  • Short maneuvering with a tractor-trailer

    That is a strain on one point, time and again in the same place. Agree those boundaries in advance with your customer. That prevents arguments afterwards.

Not the weight, but the torsional load

Vertical pressure is rarely the issue with a filled gravel mat. What really puts the paving to the test is horizontal force: a wheel turning almost on the spot while parking, or a delivery van braking as it enters the site. That torsional load pushes the stones sideways and deforms the mat. In a car park, that doesn’t happen occasionally, but dozens of times a day in the same spots.

ECCOgravel absorbs that force with plastic reinforcements between the honeycomb cells. For drive-on applications, choose ECCOgravel 40: the 4 cm mat distributes the load to the base better than the 3 cm one.

The structure in brief

For ridden applications with ECCOgravel, these values apply:

  • >25 cm
    Underpinning

    limestone chippings, porphyry chippings or crushed concrete rubble (0–32 or 0–40 mm), in layers of no more than 20 cm, compacted each time with a vibrating plate compactor. Do not use brick rubble: it breaks under load and the fine fractions released in the process reduce permeability.

  • 5 cm
    Levelling layer

    limestone or porphyry (2-4, 1-3 or 0-4 mm) or screening sand, compacted and levelled off flat.

  • 8–16 mm
    Caliber gravel

    preferably angular and crushed, with no fines smaller than 4 mm. Angular grains interlock; rounded grains give way more quickly under torsional load.

  • -20 °C
    Frost-resistant

    A frost-free foundation depth is not necessary. No water remains in the open structure, and the mat stays flexible down to -20 °C, so it follows slight ground movement without cracking. 

Where things go wrong on the construction site

Under heavy traffic, small installation errors come to light more quickly. It pays to be meticulous on these four points.

  • A levelling layer that is not level

    If the mat rests only on a few points, it will only bear weight on those points, and the load ends up on cells that aren’t designed for it. Laying it flat here isn’t a finish, but part of the construction.

  • Seams in a single line

    Lay the mats in a half-bond pattern, with overlapping geotextile. This way, the forces are transferred from one mat to the next, instead of converging on a single continuous joint.

  • Compacted gravel

    Fill and level using a shovel, brush, rake and screed board, but do not compact the gravel. Compaction breaks the grains, and that break produces exactly the fine fractions that reduce permeability. Let the gravel sit 1 to 2 cm above the mats: the filled honeycombs form a rough surface that the thin top layer grips onto. A thicker layer sits loose and slides away.

  • Construction site traffic on unfilled mats

    Do not let any vehicle drive over the mats until they are filled, including construction site traffic.

  • Inspection

    Schedule one inspection after the first commissioning: level and top up where necessary. With correct construction, the paving will then remain level.

The edge: where a flat paved surface still starts to shift

A gravel surface is also subjected to lateral loads. Without an edge restraint, the infill can shift sideways and the level will sink in the outer row of honeycombs—exactly where vehicles turn onto the area. Therefore, install the edging before the mats.

ECCOborder Metalflex is designed for ECCOgravel. Combine Metalflex H60 with ECCOgravel 40: the gravel layer will then be level with the upstand. You can mark parking bays with ECCOgravel parking markers, without interrupting the build-up.