Every industry has a role to play in managing climate change and Neil Dixon believes that geosynthetics are part of ground engineering’s solution.
Unconventional, alternative and unusual are all words frequently used to describe geosynthetic solutions to ground engineering problems. This leads some to believe they are unproven rather than innovative. Also, after more than three decades, these techniques should be established and accepted, especially as Loughborough University professor of geotechnical engineering Neil Dixon believes they are key to meeting climate challenges.
“Global challenges, geosynthetic solutions and counting carbon” was the title of the joint International Geosynthetics Society (IGS) and British Geotechnical Association 16th invitational lecture delivered by Dixon in October. During the lecture he explored climate change issues and looked at previous studies on the sustainability of geosynthetics to draw together evidence the industry needs to prove its green credentials.
Dixon says his invitational lecture was based on one he delivered as the keynote at the Third Pan American Conference on Geosynthetics in Miami Beach, United States in April 2016.
“The lecture was well received and the reaction was positive,” says Dixon.
“It was aimed to be a high level look at the challenge and potential rather than go into detail and be an introduction to the conference.
“Climate and the United Nations’ sustainable development goals are a hot topic and should be driving use of geosynthetics in geotechnical design,” says Dixon.
“The sustainable development goals developed by the United Nations should be driving very high level government decisions in countries around the world and be trickling down to government-funded infrastructure projects.
“We all know that cost is still the main driver, but it is becoming more and more important to consider sustainability. We should all be aware of this, but the aim of the lecture was to present it clearly at the start of the Miami conference to put all the other lectures into context.”
Dixon does not claim to be a climate change expert and believes you do not need to be. “It is useful to understand the science and the message about climate change rather than listen to the doubters presented by the mainstream media,” he says. “The lecture presented the data and outlined the uncertainty.”
The topic of the lecture has been a long time in the making, as much of Dixon’s academic research has focused on geosynthetics in engineering design, but the basis of the lecture started almost 10 years ago.
“In 2008, the IGS ran a European conference for geosynthetics which did well financially, and the funds generated were put forward for training and research to benefit all members,” he says.
Loughborough has a four year engineering doctorate programme where students work with a sponsoring company so Dixon proposed that part of the funding could be used within the programme to support sustainability research.
Jamil Raja worked on the IGS-sponsored project which was follow on from a Waste and Resources Action Programme project, but looking at the issues in more depth. The study examined processes and embodied carbon in geosynthetics in more detail and it is that detail, along with climate change evidence, that Dixon presented during his lecture.
“Geosynthetics were recognised as being sustainable and lots of claims were being made, but as an industry we needed the independent evidence to prove it,” he says.
Dixon believes that the evidence is just part of the challenge. Acceptance of geosynthetics as a primary solution, rather than an alternative, and education are other issues that need to be tackled.
“Terms such as ‘unconventional’ and ‘alternative’ are often still used with geosynthetics, which is often meant to demonstrate innovation, but the impression many get is that they are unproven and present a risk,” he explains.
“There is still a lack of knowledge and clients need to understand.”
Through the IGS funding, a film has been produced to explain the benefits to clients and Dixon says this uses sustainability as the main hook.
“Design using geosynthetics is still not taught as part of a civil engineering degree and is often still viewed as being new,” he says.
Educating the educators is something that Dixon is working on.
“Geosynthetics are not covered in text books, so getting civil engineering professors to deliver just one lecture on the subject is a start,” he says.
“The other challenge is that there is a lot of competition within the sector about which manufacturer’s system is better than another. But they need to come together to effectively compete against other geotechnical solutions.
“If not considered at the start of a project, they will always be considered as an alternative,” he adds.
The UK was the first to have design codes for geosynthetics with BS8006 published in 1995. But this has also created barriers to that being a driver.
“It is great to codify design, but BS8006 was based on using high quality fill, although it is possible to use marginal soils with geosynthetics, and it is here where the real savings can be made,” says Dixon.
According to Dixon, the code stifled the use of these marginal soils and focused design on quality fill.
One of the first uses of geosynthetics was on the M62 where it was used to reinforce colliery spoil. “Geosynthetics were always intended to do things with the fill material that would otherwise have been impossible,” he says.
So geosynthetics have the potential to meet climate challenges, but could the products keep evolving to provide even better solutions? Dixon believes that further innovation is possible.
“In terms of development of the material used within geosynthetics, I have heard about the use of graphene within the weave,” he says.
“At Newcastle University they are looking at delivering electrokinetic stabilisation using geosynthetic materials with conductive properties.
“It is also possible that nano treatments to the surface could be used to remediate or manage soil contamination.
“Maybe 3D printing could create possibilities with instrumentation printed within the material.”
Dixon says that fibre optics have already been put into geomembranes to look at strain but these have been bonded, and it is currently difficult to get them to act in the same way as the geomembrane. Yet he believes that if these could be woven into the material they could give great information on strain that would be fed back into design to improve future systems.
While many of these materials are some way off being every day solutions, Dixon hopes that attendees to the invitational lecture will have gone away knowing that there are studies to evidence the sustainability and engineering aspects of existing products.
“The lecture should have given them confidence to introduce geosynthetics to their projects as a mainstream solution and use the evidence to present a strong case for the benefits,” concludes Dixon.