In civil engineering and geotechnical usages, the durability of reinforcement materials constitutes an important aspect of the length of life that the infrastructure is protected for. Of the various solutions that have arrived at an interpretation of how to reinforce slopes and structures, geogrids have become the go-to option, with the added advantage of getting the material ready for a possible long life of service being a prime requirement. Our focus here is on how a PVC coated geogrid enhances durability, where they are found, and the benefits of having them in an array of construction projects. What are the benefits of a PVC coated geogrid?
A PVC coated geogrid is a geosynthetic reinforcement that is formed by coating high strength core such as polyester (PET), or polypropylene (PP) with polyvinyl chloride (PVC). The coating process forms an outer defence around the cores, making them resistant to environmental attack such as moisture, UV attack, chemical attack and mechanical degradation. Compared to uncoated and conventional geogrids, the PVC coating confers several advantages and functionality to the resultant geogrid system. Commonly available are uniaxial, biaxial, and multi-directional so-called geographical grids, with certain advantages in retaining walls/road embankments/slopes/landfill applications and so on being gained by the different configurations. What contributes to the durability of a PVC coated geogrid? Why is it ‘superior’ to uncoated and conventional geogrids in terms of durability? Let’s explore the various factors. Protection against environmental stress is conferred by the PVC coating which acts as a shield.These environments may have high exposure to UV radiation, extreme temperatures, and aggressive chemical action. The coating itself acts as a barrier preventing direct contact of moisture, salts, acidic soils (which traditional geogrids suffer degradation). This is one of the reasons for better life cycle durability of PVC coated geogrids.
Better mechanical protection
The geogrid fibres give initial tensile strength. This coating or foil gives other protective benefits. Abrasion and puncture risks to the core material during construction and for the overall product when in place are reduced. Such properties assist in heavy construction sites, coarse backfill material, and any construction material subjected to construction traffic. Strong core fibres with a PVC base coat are designed to carry further long term loads when installed.
Chemical resistance
PVC coated geogrids are very resistant to site chemicals, including acids and known hydrocarbon materials. These are unable to eat into the product. In cases like landfill or industrial site stabilisation recovering ground, the PVC foil coating helps keep up high levels of service for decades.
Resistance to microbial or environmental attack. Some soils have bacterium that attack the plastic over time.The main feature of Protection is the PVC coating which protects the Geogrid underneath from attack by a hostile environment. This is desirable when the geogrid is utilized in wet soils, soils rich in organic matter or where ground biological activity has the potential to degrade the geogrid.
Uses of PVC Coated Geogrids
Retaining Walls and Slopes – PVC coated geogrids have been incorporated into the construction of reinforced earth retaining walls and slope stabilisation.
Road Embankments and Pavements…to form a composite and stable foundation for flexible pavements.
Landfill reinforcement…to allow the construction of landfill slopes and waste layers to be reinforced, particularly in the chemical environment associated with landfill leachate.
Soft Soil Stabilisation…to provide a better foundation for structures, roads, pavements. In addition to preventing softening of roads as a result of specific vehicle loads. For example, lorries and tripping hazards when cutting footpads in pavements.
Benefits Compared with non-coated Geogrids
Longer Life – many decades longer.
Lower Maintenance – as the reinforcement will be less susceptible to degradation.
Better Performance in the Harsh Environment – the component has been preserved from degrading influences.
Greater Safety of installation – the coating reduces the risk of abrasion to the installed product, thus minimising inconvenience to operators and damage at the site of use.
Selecting the Right Geogrid
Naturally this will depend on the specification and thereby structure to which it is to be applied. Particular reference should be made to the tensile strength to soil interaction and length of service required. Products include, but not necessarily limited to, TGSG3030TGSG3535TGDG120KN…these various products afford different tensile strengths and elongation behaviours.
Conclusion
The PVC coated geogrids combine the protective and preservative effects of the coating and rigidity and flexural strength of the geogrids themselves.
Provided that a strong Geogrid is selected and applied, with respect to the structure being reinforced, PVC Coated Geogrids provide additional resistance to degradation from the environment, utilise chemicals designed to resist biological attack, thus reinforcing: retaining walls, slopes, embankments and soft soil.