Guipure Architecture

Pascal Pinet:

- Ductal^®, or UHPC (ultra high performance concrete), is an ultra-high-strength dispersion-reinforced concrete with high compressive strength. The most valuable thing in Ductal^® for architects - a combination of phenomenal design and decorative qualities. Finishing is not required for this material: its external beauty is already unconditional. Elements from Ductal^® produced at the factory, this guarantees the high quality of installation and construction work. To improve structural properties and eliminate reinforcement in Ductal^® fiber is used. It can be of three types: steel, polymer and glass-plastic. Steel fiber is used to create and strengthen various engineering structures.

Ductal^® produced in two premixes: gray and white. When we apply a white premix (for example, in facade panels), the use of metal fibers can lead to the formation of rust spots on the surface. Therefore, stainless steel fiber is used for white facades. Glass-plastic fiber is used in the production of panels by spraying onto the formwork.

- There are many types of fiber-reinforced concrete on the market - what is the difference between Ductal^®?

- Good question. Fiber-reinforced concrete is not the same as UHPC (Ultra High Performance Concrete). These types of concrete are fundamentally different. The concrete matrix is completely different. It's all about the packing density of the matrix, which in Ductal^® very high, and in ordinary concrete there are rather large pores. Thanks to this, Ductal^® has a very high water resistance, strength and surface smoothness. The maximum strength class of general concrete is B80. Architectural Ductal^® has a minimum strength of B100, and Ductal^® for engineering structures reaches strength B150 and higher. This is colossal strength, comparable to metal. Over time, the surfaces of ordinary fiber-reinforced concrete lose their properties and appearance, and Ductal^® this does not apply.

- How durable are Ductal buildings?^®?

- First building from Ductal^® appeared in Madrid in the 1990s. The material was invented a long time ago, but it began to be actively used only 10 years ago. When the material was invented, it had phenomenal strength under laboratory conditions - up to 500 MPa. Now it is 130-250 MPa, which is significantly higher than the strength of ordinary concrete, that is, Ductal^® much more durable material.

- As far as I understand, Ductal^® opened up new expressive possibilities for architects. Let's talk about specific buildings.

- Yes this is true. And we ourselves do not fully know all the options for how elements from Ductal might look like.^®, therefore, are interested in working together with architects. But what has already been built is promising. The most famous of the implemented projects: Mucem - Museum of Civilizations in Marseille, Jean Bouin Stadium - Jean Bouin stadium in Paris by architect Rudy Richotti. Currently under construction a TGV railway station in Montpellier with prefabricated roof elements in white Ductal^®… Designed by Jean Nouvel, a tower with Ductal façade elements is being erected in Marseille^®… Ductal building coming soon in New York^® designed by Renzo Piano.

- The lace façade of Mucem, the Museum of Civilizations in Marseille, is something unique. I've never seen concrete look like women's underwear. Is that to consider the predecessor of the house of Andrey Burov on Tverskaya Art Deco style … How the lace from Ductal is arranged^®?

- The facade mesh with a "thread" thickness of 10 cm consists of 6 x 3 m panels. They have not only decorative, but also constructive value. The panel rests on the foundation slab and the second panel rests on the first. There is a space between them and the internal façade made of columns (also from UHPC). And in this space, two pedestrian bridges made of our material are suspended on reinforcing ropes. Thus Ductal^® at Mucem provides both an aesthetic and a constructive solution.

These façade panels and their top level fittings were manufactured at the factory. In the assembly of the structure, everything is mechanized, quickly and conveniently. There are four types of Ductal panels used on site^®… According to the project, each panel was rotated 180 degrees vertically and horizontally, so we got 16 different combinations of patterns. The design of the panels was created by Rudy Richotti, and the options for their joining were selected by the designer, so that the edges of one pattern coincide with the edges of another in a universal way. It turned out to be a kind of engineering and art game.

The same designer helped to draw the pattern and connecting elements for the Jean Bouin stadium. If Mucem was created as a new object, where Ductal^® was originally laid down in the project in the form of an architectural and engineering solution, then it was different with the stadium. Ductal architectural shell^® at the Jean Bouin Stadium looks like a new elegant façade on an old building. This rugby stadium built in 2012 was covered with rather rough metal trusses, and the shell appeared later.

We used thin panels 3-5 centimeters thick and 9 meters long with glass inserts: three types of panels for the roof and two for the facade. The connections of the parts are thought out in such a way as to ensure the drainage of water from the roof. We didn't need to drain water from the side facades, so we made the lines more streamlined and smoother. The pattern looks like tree branches. Please note: the famous football stadium from the 1970s, the Parc des Princes stadium, is located nearby. At one time, it became necessary to protect the stands from precipitation and actually build a building on the building, which was both difficult and time-consuming, and the roof would still require maintenance later. No additional waterproofing is required for UHPC roofing: no aluminum cladding, bituminous coatings or other solutions.

Development of the Ductal application theme^® for civil engineering objects, the station at Monpellier can be considered. The roof of the Montpellier TGV station is made of concrete elements 18 m long and only 4 cm thick (only the stiffener reaches 30 cm). This lightweight Ductal dome^® is both a structure and a decoration. If the architectural panels of the Jean Bouin stadium were based on trusses, then the roof of the Montpellier station is self-supporting. And the decorative holes in the dome of the roof are filled with glass, which was molded into parts at the factory. These elements use a white premix and stainless steel fiber. Thus, UHPC roofing elements can be self-supporting. Due to its resistance to various media, Ductal^® can be used as a roofing material, it does not require additional protection.

- To create the architectural facade of the Ductal building^® irreplaceable. What else can Ductal do^®?

- I would like to tell you about the building of the Louis Vuitton Foundation in Paris - the Louis Vuitton Foundation by architect Frank Gehry. All exterior walls of the foundation are made of architectural white panels with unique geometry. When it came to their production, we used a special 3D vacuum formwork, the technology of which was patented. The program independently set the radii and form of the formwork, geometry, after the formwork was filled with Ductal^®… This is how the unique curved shapes of the finished product turned out. These white flexible walls carry the famous glass sails of the Louis Vuitton foundation.

- Ductal^® only suitable for unique objects?

“Many people in France and Europe say," Well, your innovative material is suitable for museums and theaters. " But this is absolutely not the case. For example, Jean Nouvel's tower in Marseille - Jean Nouvel Marseillaise tower - the office of a real estate company. Ductal^® suitable not only for "aristocratic buildings", but can also be a very democratic material. We have standard panels of the same shape and thickness (15 mm), suitable for standard designs.

- Tell us more about the Jean Nouvel Tower. This is the first use of Ductal^® in high-rise construction?

- The height of the building is about 140 meters. For France, this is a skyscraper. The building needs protection from rain, wind and sun. The various façade elements of this skyscraper are made of Ductal^®, the use of which is justified by protection from the sun and moisture. Jean Nouvel designed the façade to be multicolored, and although Ductal^® can be painted in bulk, in this case, for the sake of the architect's plan, only surfaces were painted. The details of the facade are very thin and at the same time dimensional. It is hard to believe that they are cast in concrete.

- How easy is it to mount elements from Ductal^®? Does the qualification of the workers matter when installing them? On Russian construction sites, it is often not very high.

- Oh, the workers in France are the same. In order to minimize the influence of the human factor on the construction site, we pay special attention to the development of high-precision formwork. During the production of concrete elements at the factory, all fasteners are molded into the product with high precision, which eliminates installation errors. We spend more time and money on metal molds, but we get the perfect result during installation.

For example, a kindergarten in Paris - La crèche Pierre Budin. All architectural panels are made of Ductal^®… All elements are unique, while they fit very precisely, as they are made at the factory. Panel joints are practically invisible. Each element has embedded fasteners, including rubber seals and insulation. This significantly speeds up the installation work.

By the way, I noticed that construction work in Russia is carried out at a high level.

- Tell us about the structural properties of Ductal^®: Is it worth using it in all parts of the structure, or can you do without it somewhere?

- Bridge of the Republic in Montpellier - Monpellier Republic bridge, demonstrates the structural properties of Ductal^®: bridge T-beams with a length of 23 meters are made of it. The bridge supports are also made from UHPC. At the same time, the bridge deck slab is made of ordinary concrete, since there is no technical need to make all the elements from our ultra-high-strength dispersion-reinforced concrete. Ductal^® it makes sense to use only where it gives an advantage.

Comparing the cost of Ductal^® with ordinary concrete, it is more expensive, but you need five times less material to achieve structural strength. Due to the use of factory-made elements, installation is typically five times faster. The quality of construction is much higher. Optimizing the construction process with Ductal^® obvious.