By Bob Koerner
Perhaps it’s mainly perception, but I think that the reason geosynthetics have made significant inroads in myriad applications is based heavily on cost. Cost enters into the decision to use geosynthetics (over traditional materials) in one of two ways:
- to provide equivalent performance at a lower cost.
- to provide better performance at an equivalent cost.
Either way, cost appears to be the pivotal issue of whether to use geosynthetics for whatever application is under consideration.
The above said, perhaps we (really everyone involved in geosynthetics) are overlooking a major feature that could, or should, go side-by-side with cost. That feature has to do with sustainability and, more specifically, with the low carbon footprint of a geosynthetic solution compared to a traditional material solution—e.g., one using concrete, steel, gravel, clay, etc. In this regard, the carbon footprint of the contrasting solutions can be readily quantified insofar as their respective carbon dioxide (CO2) emissions.
At the outset, recognize that there is a large and growing body of information available for calculating CO2 emissions.* A recent report, however, has taken this type of general information and distilled it directly into the geosynthetics mainstream. The report is titled “Sustainable Geosystems in Civil Engineering Applications” by the Waste and Resources Action Program (WRAP), May 2009.
This report is authored by representatives of 16 U.K. organizations of which one-third are geosynthetic manufacturers. In it are five worked-out case studies (see Table 1, above). They address both slopes and walls and show that when replacing traditional material solutions with geosynthetic reinforcement materials, costs are greatly reduced (as expected) and the CO2 footprint is reduced even more. The differences shown in the table above are apparent.