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INTERVIEW - Christian Cremona, Technical and R&D Director at Bouygues Construction & Bouygues Travaux Publics

News International-French

2 Dec 2019

Introduced for the first time in 2005, the notion of smart cities gives greater substance to the quest for energy efficiency, smart habitats, smart networks and soft mobility in a sustainable urban environment. The “Smart City” market is a rapidly growing one. According to a report from Grand View Research, an American business consulting firm, this market will be worth $1,400 billion by 2020. Here, the Bouygues group, a major player in the field of construction and civil engineering, presents its vision and its solutions involving composites to address this 21st century challenge.

Christian Cremona, Director, R&D Materials and Structures, BYCN Technical Director, Bridge and Materials Engineering, Bouygues Construction &; Bouygues Travaux Publics
JEC Composites Magazine: How would you define the smart city concept at Bouygues? What kind of issues does it raise for a group such as yours?
Christian Cremona: An open approach to the mobility of goods and people was initiated in 2018 in collaboration with stakeholders and users with the objective of defining an ideal vision of smart mobility by 2030. Bouygues Construction analysed the supply and demand of this sector based on the habits and expectations of individuals. Local authorities, institutions, companies, start-ups, sociologists and real estate professionals, among others, took part in the debate, sharing their own views and gauging their ideas against a sociological approach that included talks from experts and foresight workshops.

The French Observatory of Emerging Uses in Cities (OUEV) conducted a poll of 4,000 people – representative of the French population and also including 3,000 European citizens – to assess how individuals perceive their city and to identify any new habits in urban mobility.


Five topics were chosen as a basis to investigate the future of cities. These topics can be seen as the key issues pervading the current debate on smart mobility for the future:

1 - Mobility in suburban areas,
2 - Importance of data for mobility services,
3 - Emergence of autonomous vehicles,
4 - Low mobility solutions where city stakeholders can provide local services in and around built-up areas (accommodation, offices, etc.), and
5 - Mobility of goods.Evidently, mobility is a vast subject and has become one of the main concerns expressed by our customers with reference to smart cities.

JEC Composites Magazine: The term “composite material” is very broad. How does Bouygues Construction define it?
Christian Cremona: Composite materials are increasingly prevalent in the building and public works sectors. There is, however, some confusion among construction engineers who use the term “composite” to describe an assembly of materials with different properties: steel/concrete, wood/concrete, etc. We tend to forget that in other industries, it refers to materials comprising a reinforcement material and a matrix of thermoplastic or thermosetting materials. Composite materials are used in many applications, whether for structural work or interior/exterior finishings. When it comes to finishings, there is no denying that composites have invaded our homes, from floor to ceiling.

Yet composites are also a key component in the design of outdoor equipment; they will play a major role in the connected cities of tomorrow thanks to their low weight, strength and durability. This is particularly true for the deployment of 5G networks.


Self-sufficient building under construction in Grenobles, France, in which composites are used in the solar panels that generate energy

Self-sufficient building under construction in Grenobles, France, in which composites are used in the solar panels that generate energy

JEC Composites Magazine: Can you elaborate on some of your recent developments and applications in construction that use composite materials? Is the current trend set on improving existing systems or more so on implementing new materials?
Christian Cremona: There is still ample room for progress in structural materials, even if we are using composites in various fields: composite panels for façades, composite slabs for ceilings and walls, composite tiles for roofs, shutters and doors, etc.  However, their higher cost can be a disincentive in a business model with margins that are already tight. Investment in this type of material can nonetheless help us sidestep issues such as sound pollution, weight, corrosion, etc. Corrosion is an issue that often takes centre stage in the design of structural components. In fact, one of the best examples worth citing is the use of composite materials to reinforce civil engineering works by means of adhesive bonded carbon fibre  reinforcements or fabrics. However, developing materials that are transparent to radio waves, for instance, remains largely overlooked even though the advent of 5G will undoubtedly bring this issue to the forefront in any smart city of the future.

JEC Composites Magazine: How can composite materials be integrated into the smart cities of the future? What kind of advantages can they provide in smart transportation, communication and construction solutions?
Christian Cremona: To build a smart city, we need to develop new construction practices. The public works sector initiated its digital revolution by adopting new digital tools (drones, virtual reality, digital mock-ups, etc.) to manage increasingly complex projects, while focusing more on the front and backend of structural life cycles. This also means we must review how we go about building, by using more prefabrication, modular and industrialised techniques. Composite materials are well suited to such techniques.

"Composite materials will play a major role in the connected cities of tomorrow"

Thanks to their properties (sustainable, durable and lightweight), composites should be able to claim a fair share of the urban equipment market, which is set to play an increasingly important role in smart cities. Likewise, we need to take into account the increasing use of façade materials transparent to radio waves.

The population pressure in urban environments is intensifying across the globe, setting an unprecedented pace of construction and further densification of the urban fabric, infrastructures and services.

JEC Composites Magazine: How can composite materials contribute to the development of city centres?
Christian Cremona: Being lightweight, corrosion resistant and increasingly more recyclable, composite materials open the door to more diverse methods of construction (modular) that are not only sustainable but also suitable for urban regeneration projects and new structures. These materials also boast interesting properties for urban equipment in smart cities.

Reinforcement using carbon laminates – Bouygues Construction

Reinforcement using carbon laminates – Bouygues Construction

JEC Composites Magazine: Ten years ago, the use of composites in construction was following hot on the heels of that of transport in terms of volume. Do you think the development of smart cities will put your sector in pole position in the near future?
Christian Cremona: Difficult to say. For this to happen, composite materials will have to be more sustainable.