Construction with local ressources – CoLoRe

The setting up of the CoLoRe joint laboratory, associating the Institut de Rrecherche Dupuy de Lome (IRDL) of the University of Southern Brittany and the company Laboratoire CBTP, a subsidiary of the Pigeon Group, is fully in line with the strategic axes of the Pigeon Group with the objective of reducing the company's overall environmental footprint by optimising the use of currently unexploited natural resources and by developing innovative materials with lower impacts based on local resources from the mineral, plant and/or marine world. This initiative aims to amplify the active collaboration between the two entities, which have been interacting effectively for the past three years. The acquired skills of the IRDL Joint Research Unit in these scientific fields and especially the experience of partnership research are indisputable assets in the success of such a joint public/private research structure.
The ambition of the Pigeon group for the coming years is to begin its transformation in order to optimise the natural resources extracted, particularly those currently not exploited and considered as co-products or even waste from the extractive industries, and to offer the construction and public works sectors less impactful materials.
Three lines of research are more specifically targeted. The first concerns the development of raw earth-based construction products. Indeed, one of the solutions that is gaining ground in order to limit the impact of human construction on climate change is to use natural materials that have been little transformed. Thus, there is a strong revival of interest in the use of raw earth in the construction sector. Through its activities, the Pigeon Group generates large volumes of excavated materials that could be integrated into this recovery process. Currently, the development of the use of these materials in the field of construction comes up against the difficulty of producing standardised construction elements with guaranteed target performances. With regard to its activities, the Pigeon group has the industrial know-how to prepare this type of material (extraction, sorting) and to shape it (prefabrication factory for blocks in the short term, or for massive and complete structural elements in the longer term). The LabCom should make it possible to identify the mechanisms at work at the scale of the structure of the material, in order to propose the best material/process pairing for the industrial development of these solutions.
The second line of research concerns construction products based on hydraulic binders. Concrete is currently an essential material for the construction of civil engineering infrastructures. However, its environmental impact is significant, both through the mobilisation of non-renewable natural resources (alluvial sands) and through the significant carbon impact of the manufacture of the Portland type binders currently most widely used. For this axis, two development paths are planned. The first aims to optimise the introduction of natural crushed resources extracted on the Pigeon group's sites as a substitute for alluvial resources. The second is to develop new binders that are lower in carbon than the traditional binders (Portland cement) currently used. In particular, it is planned to develop new binders incorporating the washing fines from the group's extraction sites, which are currently considered as co-products.
Finally, the third line of research will focus on materials with bituminous binders. For these materials, the objective is to develop solutions that limit the use of carbon-based binders. The objective is to develop plant-based (or seaweed-based) binder solutions to replace bituminous binders.