Towards an identity card for green concrete

NG2B was selected during the third edition of the Ademe Seed Call for projects "Managing, Producing, Valuing Biomasses". The fruit of a collaboration between Cerema, Guilde Sable Vert, BioBuild Concept, PAREX GROUP, VICAT, AKTA, UniLaSalle and ENTPE, it started on April 1, 2021 for a period of 30 months.

In order to reduce the impact of private buildings during construction, the RE2020 in particular will encourage more frequent use of wood and biobased materials. They indeed present quite remarkable environmental performances: renewable annually, they are carbon sinks, available locally and often by-products of agriculture not valued today.

France has positioned itself as a pioneer for twenty years in plant-based concretes, obtained from plant particles (hemp, miscanthus, flax, rice husk, etc.). The expertise and technical solutions that exist in France now make it possible to massify the market, especially since the development potential is very important with agricultural co-products (rapeseed, sunflower, corn, etc. .), waste recycling (bagasse, wooden pallets, etc.) or the rational mobilization of natural ecosystems (reeds, alpha, water palm, etc.). However, despite the many works carried out, the characterization of plant-based concrete is not framed by any standard. This deficiency constitutes a major obstacle to the essential conditions for market development.

The objective of the NG2B collaborative project is to establish a general framework for characterizing and classifying plant aggregates according to their origins and the characteristics that impact their performance. This framework will also take into account environmental performance in order to facilitate the establishment of the profile of aggregates and concrete and the possibilities of substitution. NG2B is also part of a sector and territory logic: its ambition is to allow local supplies.

The project is based on the many R&D work already carried out in France but also at the international level. NG2B will aim to:

• to identify the relevant characteristics to qualify and discriminate these plant aggregates,
• to identify and specify the various existing characterization methods in order to identify the relevant elements and the ranges of limit variations.

This work aims to establish an "identity card" for these aggregates, compiling the specifications likely to influence the technical and environmental characteristics of green concrete.

The approach will take care of:

• not to slow down the potential for innovation which is one of the assets of the field,
• not to exclude any solution, whatever the size of the target market.

Cerema is involved at different levels and more specifically deals with the steering of the scientific and technical committee and the coordination of the batch dedicated to the validation of procedures and characterization.

All the players in the plant-based concrete sector, from agricultural upstream to end users, will be consulted and involved in the decision-making process. In this context, the constitution of the consortium is based on strong complementarity between partners from Research & Development, agricultural sectors, manufacturers and even applicators.