“The rules of the art are non-existent for these new materials”.
Interview with Stéphanie Bondoux, Director of Certification and Assessment at Hoffmann Green.
So-called breakthrough technologies such as Hoffmann cements must undergo a thorough evaluation before they can be guaranteed and marketed. Evaluation of the material and its performance, its durability and resistance to deterioration, its environmental and health performance: everything is measured.
Focus on the Spinetta law
In France, the Spinetta law of 7 January 1978 provides a framework for liability and requires insurance throughout the construction chain. For both the client (damage-ouvrage insurance) and the contractor (ten-year insurance), insurance is an essential part of marketing a construction product. The second aspect of the Spinetta law is the requirement for technical inspection by an independent third party in the event of damage that could affect the solidity and durability of the structure or the safety of people. This regulatory context generates high standards, which are often perceived as major obstacles to innovation.
Certification or assessment?
If a product falls within an existing standard, it must be certified in order to be listed as a ‘common’ technique by insurance companies (see box opposite). For Hoffmann, only one product, H-IONA, Europe’s first carbon-free cement, falls into the category of oversulphated cements. Since it complies with an existing standard – NF EN 206/CN – it has been able to obtain CE marking in 2021. For its other products, the Vendée-based manufacturer has created new technologies, doing away entirely with clinker, the traditional basic material that sets concrete. The rules of the art are therefore non-existent for these new materials. They have to go through the assessment stage before they can be insured and marketed.
What does material assessment involve?
The first stage of the assessment is to qualify the material. Here we talk about chemistry, composition, etc. What emerges is a veritable identity card for the material. For example, the mechanical performance of the cement (strength, compression, etc.) and its propensity for immediate and long-term deformation are assessed. The assessment then focuses on its durability over time: fifty years for a building, one hundred years for an engineering structure such as a bridge or tunnel. The tests cover damage caused by freezing, thawing, exposure to chlorides from seawater, polluted soils, etc., as well as resistance to loads depending on use, whether for housing or industrial buildings, and to damage caused by earthquakes or fire. H-UKR is the only breakthrough technology to have proven a level of durability lasting a hundred years!
How is concrete assessed?
For these new decarbonated cements, a partnership with the CSTB was necessary as soon as the company was created in 2014. The concretes are assessed on the basis of studies, university research, analyses, expert appraisals and numerous tests. The team, made up of technical representatives from Hoffmann, the CSTB, researchers and academics, and the inspection office, define the test methods and assess the results. An ATEx (experimental technical assessment), an essential passport to marketability, is then issued by an independent third party, certifying the laboratory tests. The concrete is then recognised by insurance companies and can be used in construction.
Is this prescriptive stage a brake on innovation?
Evaluation is an integral part of the innovation process. “It takes several million euros and several years to bring a breakthrough innovation to market”. At this rate, gradual optimisation is necessary, and evaluations are carried out on an ongoing basis, financed by initial marketing and fund-raising. For example, since the beginning of 2022, Hoffmann has been increasing the number of ATEx assessments, and its H-UKR cement has gone from an agreement for R+3 buildings to IGH buildings, from internal walls to columns. Currently, spiral staircases are in the process of being validated by the CSTB.
The essential carbon assessment
The subject would not be complete without the environmental and health assessment of products. The carbon impact of cements throughout their life cycle, from the extraction of raw materials to the recycling of concrete at the end of its life, is also measured with the utmost transparency. H-UKR contains not a single gram of clinker and has a carbon footprint 3.5 times smaller than traditional cement. –
This interview is taken from pages 22 and 23 of our magazine ForHum, which is currently available for free consultation on our website.