ITA WORKING GROUP 12: LOOKING AT THE PAST TO BUILD A MORE SUSTAINABLE FUTURE FOR SPRAYED CONCRETE

Sprayed concrete experts from the International Tunneling Association (ITA) Working Group 12, several of them members of EFNARC, got together early this month during the World Tunneling Congress 2022 (WTC) in Copenhagen to discuss the past, present and future of the sector. 

EFNARC president, Max Eckstein, and representatives from Bekaert, Sika, Normet and Master Builders Solutions attended in person the Working Group session, which put together some of the professionals with most expertise in the industry and several of them joined the group by video call.

The group’s Animateur and Senior Specialist Engineer at the Norwegian Geotechnical Institute, Karl Gunnar, highlighted three main topics above the rest: their most recent published report on permanent sprayed concrete linings, their current research on how permanent sprayed concrete degrades over the years and the role sprayed concrete will play in constructing more sustainable tunnels, slopes and in other applications.

The report Permanent Sprayed Concrete Lining, produced by the working group and ITAtech in 2020, touches on aspects like design, sustainability, durability or safety. It also emphasizes the need for objective certification schemes and simulator training, such as the EFNARC Nozzleman Certificate that uses a virtual reality simulator to train and assess applicants.

“We need the training process, a structured way of training and certifying people in order to get the application process right”, said Gunnar in an interview after the meeting.

As one of the most numerous and diverse ITA working groups, with representatives from companies, academia, the public sector and industry associations, amongst others, one of the challenges discussed by Working Group 12 is how to improve communication and collaboration between the members of the group and external stakeholders.

The thinner the better

Sustainability and reducing the carbon footprint was the key theme of the congress and, as with the other working groups, it will influence the actions and decisions of the Working Group 12 in the following years.

However, the group is first looking at the past, in particular, how the sprayed concrete looks after a number of years in operation, how it degrades, with the intention of using their research to improve the design and make it more sustainable in the future.

“The potential of sprayed concrete is to construct even slimmer linings, with less carbon footprint and much less concrete, so the working group 12 has a great responsibility in order to get that process documented and motivated in the industry”, says Gunnar.

In line with this, the group listened to two presentations during their meeting.

International expertise

The first presentation was held by David Oliveira, Technical Director at Jacobs, about permanent sprayed concrete linings at Westconnex M4-M5 Link Tunnels Project in Sidney, and the second one by Cristobal Menquehual, PhD Candidate at the Norwegian University of Science and Technology, about in-situ conditions and lifetime assessments of sprayed concrete linings in Norway.

The conclusions of the Australian presentation confirmed that high-performance end-hooked steel fibres achieve high-level performance ground support with only minor and expected outliers. 

On the other hand, Menquehual’s presentation, that is also his PhD thesis, outlined that shotcrete joints are in most of the cores the weakest part of the lining and determined that shotcrete porosity values near the rock should be below 21% in order to be resilient.

The group plans to meet before the  WTC 2023, which will be held in May 2022 in Athens, Greece, and is working on a new report about in-service conditions of sprayed concrete linings.

The World Tunneling Congress 2022 was organized earlier this month by ITA-AITES and the Danish Tunneling Society (DFTU) and held in the bright Bella Center Copenhagen with more than 160 innovation-sharing lectures and speakers from over 30 countries. 

THE TEMPLE FOR EFNARC NOZZLEMAN EXAMINERS CERTIFICATION

Last May, fourteen experienced nozzlemen from all over the world met at Hagerbach Test Gallery, a global hub for industrial underground expertise, to become EFNARC certified Nozzleman Examiners. Located in the Seez Valley and enclosed by the awe inspiring Appenzell alps, the gallery was founded 50 years ago by Amberg Group and it is used for avant-garde underground research and testing.

The nozzlemen came from India, Indonesia, Germany, UK, Canada, amongst other countries, to raise the bar in quality and safety in shotcrete application.

“It was a complete success. They were very nice and interactive participants. As always, everything was very well organised and prepared by Hagerbach Test Gallery, so the course ran smoothly”, said Sebastian Jehle, one of the EFNARC examiners who works for the Sika Group.

The 3-day evaluation is intended for expert nozzlemen with more than five years’ experience in wet, robotic concrete spraying and offers a mix of a practical and theoretical assessment. Applicants have to inform EFNARC of projects they have worked in and professionals with whom they’ve worked, then, the EFNARC Examiner Assessment identifies and accredits the shotcrete operators’ skills and knowledge. Nozzleman Certification will follow the successful accreditation of Examiners.

“EFNARC's goal is to achieve the highest standards in robotic wet sprayed concrete worldwide. Having earned the certification from EFNARC, the Nozzleman is at the forefront of technical development in the industry and can work worldwide”, said Christina Buxtorf-Hey, Project Manager at Hagerbach Test Gallery.

“It is very important that there are as many certificates and trained professionals for sprayed concrete as possible to ensure high-quality standards and thus safety underground worldwide”, added Jehle.

The examiner certificate is run by the Switzerland-based International Center for Geotechnics & Underground Construction (CUC) on behalf of EFNARC. CUC was founded by long-established companies with great expertise in the sector, like Sika, Amberg, Holcim, Putzmeister, Hilti, Georoc, Master Builders Solutions, Synthetic Industries and Herrenknecht.

EFNARC ensures its certification is based on technical specifications and guidelines endorsed by the International Tunnelling Association and derived from the technical and professional standards of the industry.

The fourteen newly certified examiners are now eligible to conduct:

• Nozzleman Assessments targeted towards operators with minimum three years of experience, and to hold

• EFNARC C2 training courses targeted towards both novice and experienced nozzlemen.

The next EFNARC Nozzleman Examiner Certification at Hagerbach Test Gallery is scheduled for September 20-22, 2022.

Meanwhile, Hagerbach Test Gallery will continue its cutting-edge research on tunnelling, mining, underground green farming and data centres, fire resistance tests and prototyping.

Please get in touch with us if you are interested in EFNARC certifications.

MAX ECKSTEIN ON THE PAST, PRESENT AND FUTURE OF EFNARC

The Sales Director of Aliva Equipment and President of EFNARC, Max Eckstein talks in this interview about the origins and path of EFNARC to become a reliable provider for concrete spraying equipment operator certification and a trusted reference for underground construction literature.

Eckstein has worked in construction equipment manufacturing for more than 25 years, from tunnelling to mining and infrastructure. During his time as a president EFNARC has focused on perfecting and digitalizing its Nozzleman Certification Scheme and providing valuable guidelines, best practices and recipes for the industry.

Working together to set the bar higher

Founded in 1989, EFNARC was born out of the need to unify the criteria of the main companies and experts in the construction industry and make their knowledge accessible to the public. They were competitors, but they knew that the decision to establish and promote quality and safety standards was beneficial to everyone. “It was a very personal approach, people who really had a lot of experience in this field just started to write”, says Eckstein about the methodology when the organization was born.

Originally a European organisation, EFNARC now comprises contractors, manufacturers, raw material suppliers and consultants in the specialised construction and concrete systems industry from Europe, Asia, Australasia and Latin America. It used to be based in England but its headquarters are now in Switzerland.

Some overlapping of functions between EFNARC and the International Tunnelling Association (ITA) in the 2000s opened the way for other lines of action. There was a strong need in the market for sprayed concrete certification and EFNARC saw this as an opportunity. In 2009, it launched its Nozzleman Certification Scheme, now its core activity.

Currently ITA endorses EFNARC’s scheme and both organisations work together as partners in complementing fields.

Other current activities are promoting the interests of its members and the industry in the field of specialised construction and concrete systems, in particular when it comes to sprayed concrete solutions. EFNARC is also a forum for exchange of information between its members and cooperation with European and international organisations, and the three main priorities are safety, quality and sustainability.

The value of generating expertise

What's the use of focusing on the right characteristics of the concrete if it cannot be properly applied? This question is at the centre of the change that EFNARC undertook more than 10 years ago and that puts expertise at the centre of the value chain. “I already have the recipe, but if the cook doesn’t know how to bake it then he is going to burn it”, says Eckstein.

The president of the organisation explains that their role is not to create a training centre for nozzleman. “We define how the training process needs to be done, seek feedback from the professionals and verify they know everything we ask them to know”, he says.

Then, trained examiners impart the courses on the field, in the country where they live, and provide EFNARC with the necessary documentation so they can issue a certification. An example of a place where courses can be taken is the Hagerbach Test Gallery in Switzerland, imparted by the International Centre for Geothecnis and Underground Construction (CUC).

To answer the needs of the market, nozzlemen can currently obtain two certificates:

• C2 Certificate for both novice and experienced operators imparted at numerous locations around the world  by EFNARC certified examiners, consisting of shotcrete theory basics and practical training using VR Technology. 

• Examiner certificate: an assessment and accreditation program (not a training course) run by the International Centre for Geotechnics and Underground Construction (CUC) on behalf of EFNARC. Requires three years of experience.

Leading the change in regulations and sprayed concrete certification 

EFNARC Executive committee is composed of six members, including the President, Treasurer and Nozzleman Scheme Administration, who are chosen by the members. They meet at least twice a year to discuss key topics for the industry. 

At the same time, there are four focus groups composed of specialised professionals to work on guidelines, best practices or technical specifications on fibres, mining or nozzlemen certification, amongst other topics. 

In many cases, the guidelines produced by EFNARC during its more than 30 years of history became European regulation, and they serve as vital reference for countries with less experience, so this is an important part of the work in the organisation. EFNARC literature is also used by universities and other educational organisations across the globe. 

On the other hand, EFNARC certifies professionals every year under its flagship Nozzleman Certification Scheme. “The focus of the industry is not only the quality but ensuring people’s safety. Safety starts with the one who applies the shotcrete and extends to anyone who then walks below the structures you have created”, says Eckstein.

Agility and modernisation to stay at the forefront of change 

Eckstein sees the future of EFNARC as a modern, global certification provider who is able to respond quickly to the changes in the industry and technology. The intention is to keep leading the digital transformation in the market to reach and verify professionals anywhere in the world. 

The organisation wants to increase the speed in which knowledge about specialised construction and concrete systems is shared. The expertise of the main players in the industry and the manageable size of the organization make it possible.

Collaborate with EFNARC  

If you are interested in becoming a member of EFNARC or applying for any of the Nozzleman Certification Scheme courses you can contact the organisation through our webpage or by telephone to reach our Secretary, Beatrice Jauch. She will be able to put you in contact with your local trained examiner if needed. The available dates for all courses will soon be published on our website, too. 

Our next Examiner certification will take place at Hagerbach Test Gallery in Switzerland from September 20th to 22nd, 2022.

Please join us at the World Tunnel Congress from September 2nd to 8th, 2022 in Copenhagen, Denmark and check out our courses and certifications here.