Interview: Enjoy Concrete | Applications of InWhite UHPC/UHSB in Footbridges and Buildings

Background of Enjoy Concrete:

Architectural concrete has been our passion since 2010. A passion that, day in, day out, drives us to never stop challenging boundaries. To choose fully customized projects as our vital force, to us is the only logical choice. What’s more: we keep striving for perfection. Thanks to the production process, with super smooth formwork and self-compacting concrete, all of our precast elements will live up to even the highest standards in aesthetics as well as be of the best quality, no matter the concept or the way they are used in a certain design.

Today, Enjoy Concrete is more than an established player in the world of concrete architecture. Our strong desire and determination to go above and beyond, to evolve. As a natural progression, we invested in the build of our own concrete mixing plant and in the expansion of our production plant. In order to help realize our dreams, we called on experts. An entrepreneur will indeed not survive in solitude, in a bubble of their own - which has been our philosophy for years already.

What factors influenced your ongoing preference for Extreme premixed UHPC over other branded products? 

We have always been and remain firm believers in the value of utilizing a premix for processing UHPC. Even the slightest variation in humidity or quantities can significantly impact its behavior and color.

Another reason is the invaluable support from the InWhite team regarding production technical aspects, where we gained insights into sensitivities such as thermal shock and necessary curing requirements.

Additionally, having access to a library with comprehensive documentation, including mixtures with fiber reinforcement from suppliers like Bekaert, is a significant advantage. For instance, for the bridge construction, we selected a mixture containing 80kg of 3D galvanized fibers 80/30ggp, with all test results readily available. This enables immediate calculations with the appropriate software, eliminating the need for an additional testing phase.

Could you share a few examples of Extreme UHPC/UHSB projects?

UHPC/UHSB Pedestrian Bridges in Schoten, Belgium

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The project commenced with the vision of building a maintenance-free bridge, leading to the construction of two bridges using UHPC. These bridges, boasting a span of 17 meters and a width of 2.1 meters, epitomize the resilience and elegance achievable with this material. UHSB enables reducing reinforcement coverage from 6 cm to 2 cm, showcasing its structural efficiency.

One bridge comprised two preassembled sections joined in the middle through a mechanical connection, facilitating swift installation within a single day. This expedited process minimized disruptions to canal traffic. Thanks to the rapid strength gain of Extreme UHPC, the bridges were promptly accessible upon completion.

Bridges represent intricate engineering feats, and leveraging UHPC empowers designers and engineers to design enduring and sustainable footbridges. With dimensions of 17.2 meters in span, 2.2 meters in width, and 3 meters in height, along with meticulously produced components, such as the outer stringer measuring 8.6 x 3 x 0.075 meters and treads measuring 2.05 x 0.31 x 0.07 meters, these structures embody innovation and durability.

The design of these two footbridges combines all the advantages of UHPC: extremely high strength, weight saving, and superior durability. UHPC elements are made with Extreme premixed UHPC developed by Cementir’s innovation team, composing of fine-grained, highly dense aggregates with special admixtures that improve the performance. As a result, UHPC has a compressive strength that is equally strong as steel. It can be moulded and shaped into complex and slender forms, reducing material and saving weight, allowing designers to let their creativity loose.

In addition to its strength, durability is another advantage that makes it an excellent choice for a footbridge. For example, UHPC has a very low permeability, which means it's highly resistant to water, chemicals, and other liquids. It also has a very low thermal expansion coefficient, meaning it will not expand or contract significantly with temperature changes. The superior durability of UHPC extends the life of the structure it's made of and reduces the need for maintenance and repairs. What is essential for a footbridge as it will be exposed to the elements and subject to stresses and strains as a result.

Designed by Ney & Partners, this project has garnered recognition, nominated for the FEBE Elements Awards 2022 in the precast structures category, underscoring its excellence in engineering and design.

Completion in 2022

Architect: Ney & Partners

Pictures by © Michiel Vergauwe Photography https://michielvergauwe.be/

Residence Lighthouse Corner in Nieuwpoort, Belgium | UHPC/UHSB Vertical Slats 

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Lighthouse Corner serves as a vibrant meeting point for hotel guests, Nieuwpoort residents, and passers-by, fostering daily dialogue. The large glass features at The Corner Hotel's entrance and lounge create a transparent atmosphere, while ensuring optimal privacy for hotel rooms and Residence Lighthouse Corner apartments. With a striking balance between openness and seclusion, Lighthouse Corner stands out as an architectural landmark, welcoming visitors as a gateway to Nieuwpoort.

The building façade is adorned with slats made from UHPC/UHSB, creating a bright green exterior when adorned with greenery attached to these slats. Alongside cantilevered terraces, they serve as structural sun protection for the apartments. These slats complement the natural stone façade, while window widths are aligned with the natural stone modules and finished with elegant anthracite joinery. Main contractor Constant Deblaere oversaw the site. The installation of UHPC slats presented its own set of challenges, expertly managed with proactive support from Enjoy Concrete.

Extreme UHPC/UHSB for a Durable Facade with Character

Slender UHPC slats give the façade of Lighthouse Corner its dynamic appearance. Not only do they create architectural added value, but they also serve as sun protection and at the same time form a basis for façade greenery. The fine execution and the rock-solid result are due to the Extreme branded UHPC produced by Enjoy Concrete.

As early as 2010, when UHPC/UHSB was still in its infancy, Enjoy Concrete started experimenting with the possibilities. In the meantime, the next generation of ultra-high-strength concrete is firmly established in the company. In the past ten years, this concrete has improved a lot. After testing different formulations of UHPC, we ultimately settled on Cementir’s InWhite UHPC premix ranges Extreme. A good reduction in shrinkage, the right fibre cocktail for every application and the standards are much further along. Architects are increasingly prescribing this or designing accordingly. Like at Lighthouse Corner.

Comprehensive Preliminary Study

The execution of the slats started with a thorough study. To this end, Enjoy Concrete joined forces with Ghent University. A number of concrete elements were placed on the test bench to determine the dimensioning and maximum lengths of these slats. To attach them to each other, we worked out the lightest possible connection, In the façade, these fastenings are almost invisible. In that respect, we have completely unburdened the architect and client. We took on the responsibility of fine-tuning these controllable connections, while respecting the budget. A small risk, but everything fell into place. We dare to jump for projects that we really support. We will also take this experience with us into the future.

Completion in 2022
Architect: PVL Architects 
Contractor: DEBLAERE
Pictures by ©Gerrit Devinck Photography

Louisastraat Oostende Residential Building in Belgium | UHPC/UHSB Structure Balcony 

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Louisastraat Oostende introduces a contemporary apartment building in the heart of Ostend Belgium, designed by Architect Kris Vandecasteele. The UHPC balcony, produced with Extreme UHPC by Enjoy Concrete, embodies a sleek and modern architectural style. 

Its slender design reduces weight by 40% compared to conventional concrete, all while being produced in a single piece, eliminating visible joints and maintaining a stable geometry. The quick demoulding process is employed to prevent shrinkage. The structural balcony elements are characterized by concrete strength of 120 MPa, mixing with PVA fibers and steel reinforcement. These elements boast dimensions of 2.7m x 2.7m x 0.75m with a cross-section thickness ranging from 75-85mm.

Completion in 2021
Architect: Luum architects

Graanmarkt Kortrijk Belgium | UHPC/UHSB Vertical Sun-Screen Slats

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The overall concrete façade system is composed of terraces, side walls, slats and vertical sun-screen lamels, all manufactured by Enjoy concrete. The flat vertical UHPC sun-screen elements made with Extreme premixed product have reached 120MPa compressive strength before adding PVA fibres and steel reinforcement. The slat length is 5.4m and cross-section thickness is 75-85 mm. 

The slim UHPC sun-screen lamels of this renovation project compatibly coexists in visual with the limited space given to the project. The dense white concrete surface determines the final appearance of the building with the enhanced architectural aesthetics. UHPC lamels are durable, lighter weight, high strength and can withdraw any harsh environment.

Completion in 2021
Architect: Govaert-vanhoutte architects