RMAX GeoFoam® Construction Principles
In most applications, long term design loads should not exceed the linear elastic range of RMAX GeoFoam®. Combined live load and dead load stresses should not exceed the compressive resistance at 1% to 1.5% strain.
The bottom of the installation of an RMAX GeoFoam® should be above the mean height of the water table. If there is any possibility of flooding the buoyancy effects must be considered. Common methods to counteract buoyancy are the use of sufficient overburden or use of mechanical constraint. Suitable drainage measures must be taken; on sloping sites this is particularly important.
1. Supporting Layers
The bottom layer of the RMAX GeoFoam® installation has to be supported over its entire lower face, so a plane surface, inclined as appropriate, must be prepared.
Departures from planarity should not exceed (±1 cm in 400 cm). The material used is generally sand, its thickness depends on the ground and the machines to be employed.
2. Construction of RMAX GeoFoam® Installations
The RMAX GeoFoam® installation must be laid flat, with staggered joints; no voids or open joints may be left. The joints must be offset by at least 50 cm. Where there is more than one layer of RMAX GeoFoam® blocks alternating layers of RMAX GeoFoam® should be staggered. To prevent displacement of blocks during construction they should be fixed together at intervals with polyurethane-based adhesive or mechanical fasteners (e.g. barbed dowels, diameter 117 mm at distances of 1—2 m).
Any water at or near the ground surface must be pumped off until the RMAX GeoFoam® installation is covered by material whose weight is sufficient to prevent floatation. RMAX GeoFoam® does not swell when exposed to water or water vapour. Since individual EPS blocks are light enough to be easily lifted by wind when they are being transported or installed, appropriate precautions must be taken.
Once EPS blocks are in place, they should be covered as soon as possible. RMAX GeoFoam® will discolor and yellow when exposed to sunlight for extended periods of time. Although this is a surface effect only the RMAX GeoFoam® should be covered with an opaque material if exposure to sunlight for extended periods is expected.
Offcuts should not be left on site or burnt: they should be collected for recycling. Smoking and the use of naked flames should be forbidden until RMAX GeoFoam® blocks have been completed covered by non-combustible materials.
RMAX GeoFoam® should be protected from exposure to direct contact or vapours of hydrocarbons such as petrol and diesel fuel during the construction and design life of the project. RMAX GeoFoam® can be protected from hydrocarbons by the use of a hydrocarbon-resistant geo-membrane or through other physical barriers.
3. Construction Above the RMAX GeoFoam® Installation
As a rule, the sub-grade of the road distributes the load on and protects the RMAX GeoFoam® installation, while its surface constitutes the road formation. During construction it is important to protect the RMAX GeoFoam® from damage from traffic - this can be done by having adequate thickness of suitable materials, such as concrete over the RMAX GeoFoam®. Loads are spread particularly well by reinforced concrete slab, 12—15cm thick, formed in situ, otherwise strengthened layers of other suitable materials maybe used instead. Traffic in direct contact with RMAX GeoFoam® foam blocks is not permissible.
The construction of the pavement above road formation accords with usual practices and rules, but to allow adequate compaction the thickness of material in contact with the upper surface of the EPS block or of the concrete slab over it should not be less than 30 cm.
4. Embankment Slopes
The stepped sides of the installation of RMAX GeoFoam® blocks must be bounded by planes whose slopes are consistent with stability, the required profile, the covering material, and the kinds of vegetation intended. The depth of soil covering the sides may not be less than 25 cm, measured normally to the planes bounding the installation of RMAX GeoFoam® blocks.
If slopes greater than 1:1.5 are proposed and soil-mechanical considerations allow them, the soil should be secured against slip by appropriate measures, such as reinforcement with geo-textiles or gabions. Where the sides of the embankment are to be vegetated by other than shallow-rooted plants, the soil covering over the RMAX GeoFoam® installation must be deep enough to allow the roots to provide adequate anchorage.
5. Subsidiary Highway Components
If the depth of material covering the top of the RMAX GeoFoam® installation EPS core is 1.50 m or more, no special arrangements need be made for anchoring subsidiary components such as safety fences, direction signs, etc. Depths of less than 1.50 m necessitate provision of concrete anchor blocks, which can be factory-made components resting on the load-spreading course or cast in situ in EPS forms.
Cables can be laid within the EPS if necessary provided the ducts or channels required are bridged in such a way that the load-bearing capacity of the whole system is not adversely affected. Note that without special precautions, work involving welding or soldering is not permissible.