PP biaxial geogrid for road construction , 3.95mx50m/Roll,with CE certificate - HD3030

Specifications

1)PP biaxial geogrid with CE certificate
2)Materials:polypropylene (PP)
3)Tensile strength:MD/CD:15 ~ 50kn/m
4)WIdth:1 ~ 6m

The use of geogrids in low volume roads over peat is becoming increasingly popular, particularly in new roads servicing wind farm developments on deep peat. [Link to “Floating Roads on Peat”] A wide range of geogrids are available for this, from a host of manufacturers in different materials and formats. All essentially work on the principle of “interlock” between the geogrids and road base aggregates under the action of dynamic traffic loads and settlement.

Diagrams of typical geogrids and interlock. In a normal road construction roadstone aggregates are very effective in compression but not good at resisting tensile forces. A geogrid on the other hand is excellent at resisting tensile forces and dealing with tensile effects.

Interlocking forms a composite stabilised layer between the geogrids and aggregate, creating an increased stiffness in the geogrid that helps to distribute the loads over a wider area than that of a road without geogrids. A geogrid stabilised floating road does not eliminate settlement but the geogrid makes it better able to distribute the loadings across the width of the geogrid and as such helps to reduce differential settlement over weaker areas.

The key to achieving effective interlock with a geogrid is having the correct size and shape of aggregate relative to the geogrid being used. This will depend, among other factors, on the relative geometry of the geogrid and the aggregate. Ideally, there should be such an intimate match between the geogrid and the aggregate that the interlocked “composite layer” is created. Round gravels, moraines and large stones are not therefore generally suitable for use in the interlock layer. “As dug” material may be suitable for use in the interlock area provided that it is sufficiently well graded and angular to produce interlock.

Photograph of double layer geogrid installation being laid, 450mm apart, using crushed rock aggregate to creat the interlock.

A system of two geogrids usually produces a stiffer road structure than that of a single geogrid and this can help to minimise differential settlement across the peat. A separator grade geotextile should be used below the base geogrid where there is the possibility of fine materials migrating into the aggregate layer. Fines from the subgrade soil can reduce the effectiveness of the geogrid/aggregate interlock and consequently affect the performance of the finished road. Subgrade soils with a fines content >15% should be considered as a fine material and treated with a separator geotextile.