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A world first and a true milestone in the Dutch engineering and concrete industry: Waco -in cooperation with FDN Group- has successfully produced the first maintenance-free lock gate made of ultra-high strength concrete (UHSB). An interview with Ron van Boven, director at Waco, about the process that preceded it, the successful result and the added value of the Concrete Valley Group, of which Waco is part.
"The development of this innovation began in 2018," Ron begins, "when FDN Group, in collaboration with the Province of Groningen, designed a lock gate made of ultra-high-strength concrete with a core of EPS, expanded polystyrene." He explains that this lightweight core saves weight while providing exceptional pressure resistance. "It can handle the same high pressure as steel. And although material research and design went smoothly, pouring a UHSB sluice gate proved complex." According to Ron, this was mainly due to the stringent structural requirements for lock gates. "In addition, little water is used for the concrete mix and the mold is complicated because of the polystyrene sections under which the concrete had to flow." A lock gate made of concrete has been used before, but it proved too heavy for widespread practical applications. After three previous failed attempts, Waco's specialists did manage to successfully produce the lock doors in the first quarter of this year according to FDN's implementation protocol. "And we are immensely proud of that," Ron continued.
It is a very innovative development, especially when you know that virtually all the lock gates in the world are or will be made of wood or steel. Materials that require considerable maintenance and have a limited lifespan compared to concrete. "Especially when it comes to products applied at sea," says Ron. "In those conditions, wooden doors, for example, need to be replaced every 25 years or so, while steel doors need a new, often dirty, coating against rust after 10 to 15 years. In contrast, if you look at concrete structures, they offer a maintenance-free life of at least 100 years."
The ultra-high-strength concrete doors, including their buoyancy thanks to the polystyrene core, are as heavy as the steel and wood variants and have a strength class of C200. "Unprecedentedly high compared to traditional concrete, which has a strength class between C20/25 and C30/37," Ron knows.
"Due to a higher density of the concrete mix, the use of steel fibers and special fillers, UHSB is as much as 10 times stronger than traditional concrete."
The concrete lock gates, measuring 7.3 by 5.3 meters and 0.4 meters thick, were produced on behalf of the Province of Groningen and co-financed by the Province of Friesland. Ron: "They will be installed -after the sailing season, i.e. in October- in the Robbengat lock in Lauwersoog. This new, considerably more durable variant will replace the existing wooden lock gates."
This groundbreaking achievement opens the door to a whole new generation of sustainable infrastructure. "You can make it into all types of lock gates, but you could also use it to replace the steel sliders in the Eastern Scheldt storm surge barrier and other storm surge barriers." The big advantage according to Ron is its maintenance-free nature and long service life. "We have now proven that complex products can be produced this way," he says, indicating that it could even be used to build offshore wind turbines made of concrete instead of steel.
Since 1888, Waco has been a specialist in precast structural and architectural concrete structures. "Our concrete solutions are characterized by engineering, high quality and realistic perspective," says Ron. "In particular, we see in engineering and smart production processes the solution for the ever-increasing demand for sustainable and innovative construction. And especially for projects that are becoming increasingly large-scale and complex." For projects that deviate from the standard, Waco produces a custom element for each detail if required. "In our own factory, we do this sustainably and completely under climate-controlled conditions," Ron adds. The prefab elements ensure that work on the building site is kept to a minimum and that construction can be carried out quickly. In this way, Waco provides water safety, high-quality infrastructure, high-rise and utility buildings and efficient industrial solutions.
Waco doesn't just innovate and experiment in terms of products. "Our ambition is to create a minimal footprint with our entire business operations," says Ron. "Because sustainable development and production is high on our agenda." He explains that the strategy therein is based on the policy plan created by Concrete Valley Group of which Waco is a part. It is a young, fast-growing organization that at the same time wants to make the concrete sector more sustainable and minimize its own footprint. "Of course we can't do that alone," says Ron. "So we pool and share our knowledge within the Group and seek joint partners who support our mission and help us achieve our sustainability goals." By implementing multiple sustainable changes within its production processes, raw materials and operations, the Concrete Vally Group is working toward carbon-free and energy-neutral production by 2025.
Another great project is the engineering and production of precast concrete elements for the main supporting structure and wall cladding at Bond Street subway station in London.
Not only Concrete Valley Group, but the entire concrete sector in the Netherlands feels the responsibility for sustainability. This is evidenced by the fact that as many as one-fifth of the certificates issued by CSC have gone to the Netherlands. CSC, which stands for The Concrete Sustainability Council, is the global standard for sustainability and responsible sourcing of raw materials in the concrete supply chain. The requirements of the CSC are stringent. Reporting is done according to the Global Reporting Initiative standard to ensure uniformity. "Whoever passes the inspection can be justifiably proud," says Ron. "In the Netherlands, the CSC inspection is conducted by Betonhuis, the trade association for concrete companies in the Netherlands to which Concrete Valley Group is affiliated. Betonhuis recently published its second Dutch CSC sustainability report. "In it you can read that Concrete Valley Group has achieved CSC Gold in 2023 and of course we are extremely proud of that as well." Ron thinks it's a great development that more and more concrete companies are joining the CSC. "You could say that the Netherlands is really a trendsetter in the field of sustainability, especially because participation in the certification program is voluntary and because compared to the global average, the Netherlands actually already scores very well."
Concrete Valley Group works for architects, developers, governments, housing associations and contractors developing architectural and functional projects. To do this, they provide the engineering, innovative molds, materials and techniques to create these designs. Within the Group, Waco is the specialist with more than 100 years of experience in high-quality, complex precast concrete projects, such as the Afsluitdijk. "In 2021 we were awarded the contract for the engineering, production and delivery of six precast concrete suction bells and volutes that make up the pump houses for the pumping station in the Afsluitdijk," says Ron. "A complex job where precision is paramount." Ron explains that in order to guarantee the required pumping capacity (moving 235,000 liters of water per second from the IJsselmeer to the Wadden Sea), the pump blocks must meet the highest requirements. "They are therefore completely custom designed and made. The so-called snail houses are constructed from thirteen elements in which the reinforcement is bent in a special way. For this, special molds were also developed using 3D models, to check and compare with the theoretical models."
"They are also increasingly finding us outside the Netherlands when there is a need for specific precast concrete solutions," says Ron, explaining that Waco has been allowed to supply elements in Malaysia for another pump supplier. He also mentions some projects in the UK that Waco has worked on. "A great project is the engineering and production of precast concrete elements for the main supporting structure and wall cladding at Bond Street subway station in London. We have also been involved in designing and producing a variety of precast concrete facade and GRC ceiling elements for the new headquarters of the Royal Academy of Dance (RAD) in London."
In addition to projects in the civil sector that often involve specific requirements in concrete strength, the companies within the Group also develop and produce architectural solutions. Ron mentions several striking and structurally challenging projects to which Concrete Valley Group has been able to make a valuable contribution. "Surely the most striking project is the sustainable HAUT Amsterdam, for which façade elements were produced. The iconic facade of the Westfield Mall of The Netherlands was also made by mbX (part of the Group). Currently Waco is working on the Bajes Kwartier in Amsterdam, for which we are producing 22-meter long handrails for the benefit of the bridge girders."
It may be clear that Waco, part of Concrete Valley Group, is the reliable and experienced partner for large-scale and complex projects that deviate from the standard, where custom concrete solutions are needed. Whether that is for the civil sector or in architecture. "We do that in a sustainable and innovative way where we combine smart engineering with technically innovative methods," Ron says in conclusion.
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