What role can plastics and geogrids play in sustainability?

by Andrew Lees, on 06-May-2021 04:06:26

What role can plastics and geogrids play in sustainability?

Recently, President Joe Biden hosted a virtual Leaders Summit on Climate – proof, if any is required, that sustainability continues to be a key issue in every field across the world. The summit focused on reductions in emissions, as well as a number of other global issues that impact on today (and the future)’s climate change. One of the major concerns in the construction sector, for example, is the use of non-renewable resources, including aggregates, and another focus is plastics. And yet the two issues are more closely linked than people realise.

The downside of plastics

Plastics as we know them have been used for approximately 100 years and in that time, very few of the plastics created will have been able to complete the natural degradation process, due to the chemical structure of their makeup. In the last 70 years, an estimated 6.3 billion tonnes of plastic has been produced worldwide, with just 20% of this being recycled or incinerated. Consequently, large volumes of plastic waste have entered the environment and this impacts ecosystems, as well as adding to other key sustainability concerns. Single-use plastics, and those which will eventually be thrown away, can indeed be seen as having a significant downside.

In defence of plastic geosynthetics

It is ironic then, that one family of plastic products – geosynthetics - should be able to achieve so much in working towards the protection of the environment. Geosynthetics have now been used in the construction of infrastructure projects for over fifty years: they extend road service lives and conserve water resources, they minimise land disturbance, control soil erosion and protect groundwater. They also reduce on-site excavation and fill placement, reduce the requirement to transport bulky construction materials, facilitate faster and simpler construction, extend infrastructure design life and reduce maintenance requirements.

Beverley TVAlue
Tensar geogrids helped reduce carbon footprint at Beverley Sewage Treatment works by 40%

Geogrids: Background

As well as this impressive list of uses for geosynthetics, much of the environmental benefit accrued involves the reduction of aggregate needed for road and rail projects, as this is environmentally very expensive to extract, transport and place. Geogrids were invented in the late 1970s and can considerably reduce aggregate usage and minimise environmental impact. Geogrids can reduce the need for such quantities of aggregate in construction – specifically in many cases, road pavement construction.

Geogrids: General Benefits

Geogrids can provide significant cost savings at the point of construction: they reduce the quantity of earthworks needed for engineering projects; they accelerate construction and improve long-term performance, facilitating lower incidences of repair and the associated disruption. An appropriate geogrid used in a well-designed earth-retaining structure or pavement will combine the use of plastic, with the least amount of resource (such as aggregate, concrete or asphalt) to support the maximum life of any structure. Tensar routinely demonstrate this with our applications, by offering value-engineered analyses and high efficiency geogrids.

Green Park Academy Site Aerial View 2 (3)
Tensar T-Value method, which considers the full benefits of stabilising geogrids helped to achieve 50% savings in carbon emissions at Green Park Primary Academy. 

Geogrids: Specific Benefits

To return to the road pavement construction example, the amount of materials in the capping layer of a road pavement – usually aggregates or cement stabilised soils – can be reduced by the inclusion of Tensar geogrid. This means less production impact, less initial transport emissions and less need to repair and maintain surfaces in future: again minimising environmental impact. The incorporation of Tensar geogrid in the subbase layer of a road also enables a reduction in the thickness required. In this way, geogrids can strengthen and stiffen compacted aggregate layers to such an extent that they exhibit better load bearing performance than layers twice as thick, built only with aggregate.

To reiterate - What role can plastics and geogrids play in sustainability?

Plastics fall in to several categories: some are polluting our environment and will cause ecological problems for the future. Others – such as geosynthetics – are more of a solution than a problem; correctly produced and utilised, they support a sustainable way forward that must be considered in future design projects, in all fields.

Sources:
www.geosyntheticssociety.org
U.S Geological Survey
The Economist 3 March 2018

Comments