Precaster
Jean-Yves Jousselin runs Jousselin Préfabrication, and is one of the French specialists on the subject of Ductal®. He has invested time in using and understanding Ductal®. Jousselin has worked on jobsites such as the sunshades at the Doua campus, strengthening his technological expertise on both conventional and fiber-reinforced concretes.
“Ductal® has added to our global level of skills and performance”
How did you discover Ductal®?
Jean-Yves Jousselin – We have always followed new building materials with great interest, and have been partners with Lafarge on development projects.
We started working with the CERT Structure engineering office on the construction work at the Félix Landreau School in Angers.
There we made the floor reinforcement columns and then went on to making the sunshades for the Doua campus in Lyon.
Is the material easy to use?
Ductal® is a high-performance material which requires challenging technological control and great accuracy. The production procedures are also exacting with respect to weights and we had to develop specific tooling and set up a tailor-made concrete plant and a specific workshop.
You have to scrupulously follow the exact timing for the production and mixing plus you must use polyurethane or silicone molds which can be relatively expensive.
However, use is relatively simple, because Ductal® is a self-leveling concrete. The constraint comes from the need to have perfectly impermeable formwork (to avoid leaks) and to work carefully with the shrinkage phenomena that can cause micro cracks if they are stopped.
Does that mean that not every precast producer can work with Ductal®?
Not at all, everyone can work with Ductal®. The material requires a real investment effort in equipment – we have invested some 500,000 euros in our production plant and 150,000 euros in our workshop including equipmentand staff that has to be trained. But the stakes involved are more than worth it .
Is Ductal® leading to new contracts?
Ductal® beautifully meets the demands emanating from today’s architects who like the mineral appearance of rough concrete and who can make very thin shapes, that are superb to see.
This use, however, remains a niche market such as the sunshade blades, where the cost price remains quite high. However, Ductal® has added to our expertise and enhanced our technological mastery over high-performance concrete materials, thus opening new perspectives for bigger markets for conventional concretes where we can apply the expertise we have acquired.
Pierre Pallot is in charge of research and development at Bonna Sabla, a concrete precaster with acquired, solid experience using of Ductal®; particularly in construction, structural work, foot bridges and interior layouts. Mr. Pallot, in partnership with Lafarge, has studied industrial applications such as raised flooring slabs.
“Ductal® is opening new markets for us”
How long have you been using Ductal® ?
Pierre Pallot – We have used Ductal® for over four years, first in collaboration with Bouygues to study the construction of technical flooring in the “Cœur Défense” building, then in partnership with Lafarge, for feasibility studies including the development of industrial products such as manhole covers to replace traditional cast iron covers.
Why Ductal® ?
This fiber-reinforced concrete material provides several advantages to withstand the oxidation and premature wear shown by these products.
Ductal® is full of potential for design and color, for better integration into the urban environment.
What projects are you currently working on that include Ductal® products ?
The foot bridge at the Chryso plant in Sermaises; consolidation of the clinker silo at the cement plant in la Couronne; and the Arsenal Pavilion in Paris.
In each case, Ductal® was chosen for its mechanical strength, aesthetic qualities, fire resistance and, of course, the advantages it presents with respect to light weight design and prestressing.
Is Ductal® easy to use ?
It is a demanding material. You do have to meticulously respect the protocol for use and be able to invest in the production tools, mixers or molds.
You must have good control over the casting process and know how to use molds adapted for Ductal® , particularly with respect to impermeability. You must also be able to do specific heat treatments at relatively high temperatures.
What are its advantages from the commercial standpoint ?
With Ductal®, you can make extremely thin structures with absolutely perfect finishes. The material can be cast in molds made of glass, silicone or stainless steel, providing highly original surface textures.
Ductal® throws the door wide open to new markets, particularly to architects who appreciate the finish and the thin, lightweight elements that the material can produce.
Mechanical strength can compete with materials such as steel, cast iron and other metal alloys for the manufacture of industrial products such as manhole covers and grates.
Ductal®’s outstanding fire resistance, impermeability and finesse make it the ideal material for technical flooring, particularly in the rehabilitation of old buildings.
Dominique Nowak is a commercial engineer with Betsinor, the composites maker who works with Lafarge using Ductal® on several construction sites, such as the sunshades on the Plateau d’Arbois TGV station, or the partial renovation of the façade at the National Dance Center in Pantin.
“Ductal® is a material which is still in the development phase”
What Betsinor job site used Ductal® for the first time ?
Dominique Nowak – It was in 2001, on the partial renovation of the façade at the National Dance Center in Pantin. We had a development contract with Lafarge which provided us access to Ductal®. The characteristics of this new material enabled us to reconcile the aesthetics of a thirty-year old building with the latest demanding requirements, particularly with respect to standards for strength.
Which of Ductal®‘s qualities do you value the most ?
The structural qualities, which allow for building very large, very thin elements, yet which have high coefficients of resistance.
Is Ductal® easy to use ?
It is demanding material which, to a certain extent, in my opinion, is still in the development phase. You have to know how to adapt to its particular characteristics, such as the fast setting and the need to use extremely high quality molds which are totally impermeable. And you have to be ready to invest in upgrading your facilities in order to be able to work with it.
What expectations do you have ?
Improvement in the use of the material as a sprayable product for use with complicated shapes. And, we hope that the developments which are currently underway to find semi-industrial applications which will make Ductal® more competitive, will lead to new, more affordable contracts implementing this type of new and promising material.
