Poured Earth as concrete

International audienceIn order to pour an earthen material in a liquid state, as a concrete, technologies used by concrete and ceramic industries can be transferred to the field of earthen construction. Two different methods should be employed simultaneously. The first relates to theories of grain packing that have led to models of Apollonian packing and spaced packing, commonly used for the development of cement concrete (ultra high performance concrete and self-leveling concrete). It concerns the optimization of the granular skeleton of natural materials. The second relates to the dispersion of the colloidal fraction of earthen materials. In natural soils, clays are organized as porous aggregates composed of several tens of particles. These aggregates trap water that is not used to liquefy the mixture. The dispersion of these aggregates, releasing this interstitial water, liquefies the earthen material without adding water. This dispersion is obtained by adding a small proportion (on the order of a few tenths of a percent by mass relative to the dry material) of deflocculating agents such as those commonly used for the development of industrial ceramics. The combined action of these two methods leads to a solid material that does not crack while drying, and can easily be implemented at a viscosity comparable to that of vibrated concrete with the same tools than those employed by the concrete industry (cement mixer, shuttering, vibrating needle). This new technique is particularly suited for the implementation of slabs and other horizontal surfaces, and also for vertical walls

Poured Earth as concrete

International audienceIn order to pour an earthen material in a liquid state, as a concrete, technologies used by concrete and ceramic industries can be transferred to the field of earthen construction. Two different methods should be employed simultaneously. The first relates to theories of grain packing that have led to models of Apollonian packing and spaced packing, commonly used for the development of cement concrete (ultra high performance concrete and self-leveling concrete). It concerns the optimization of the granular skeleton of natural materials. The second relates to the dispersion of the colloidal fraction of earthen materials. In natural soils, clays are organized as porous aggregates composed of several tens of particles. These aggregates trap water that is not used to liquefy the mixture. The dispersion of these aggregates, releasing this interstitial water, liquefies the earthen material without adding water. This dispersion is obtained by adding a small proportion (on the order of a few tenths of a percent by mass relative to the dry material) of deflocculating agents such as those commonly used for the development of industrial ceramics. The combined action of these two methods leads to a solid material that does not crack while drying, and can easily be implemented at a viscosity comparable to that of vibrated concrete with the same tools than those employed by the concrete industry (cement mixer, shuttering, vibrating needle). This new technique is particularly suited for the implementation of slabs and other horizontal surfaces, and also for vertical walls

Terres de Paris: de la matière au matériau

International audienceChaque année, plus d’une vingtaine de millions de tonnes de terres sont extraites en Île-de-France, auxquelles s’ajouteront jusqu’en 2030 une quarantaine de millions de tonnes excavées pour permettre l’aménagement du Grand Paris Express. Particulièrement encombrantes à stocker, importunes et polluantes à déplacer, complexes à traiter et parfois toxiques, ces excavations souterraines généralement entassées à l’air libre interpellent. « Terres de Paris » analyse le parcours de cette matière, rend compte de l’état des connaissances sur nos sous-sols et révèle un potentiel jusqu’alors inexploré pour imaginer un nouveau cycle plus vertueux, non plus de la terre aux déblais, mais de la ressource au matériau

Vidéo de documentation des essais aux chocs mous sur maçonnerie en terre crue

Cette vidéo documente les essais aux chocs mous réalisés sur deux murs en maçonnerie de Blocs de Terre Comprimée (BTC) et mortier terre.Le mur A est monté dans une configuration de cloison. Il est testé sous choc d’usages (3 chocs de 120J), puis sous choc de sécurité (900J).La validation de ces essais permet de proposer cette cloison en logements, en parties communes et en remplissage de façade.Ces essais ont été réalisés le 2 septembre 2020 aux Grands Ateliers Innovation Architecture par l’association CRAterre, l’unité de recherche Architecture, Environnement & Cultures Constructives de l’École d’Architecture de Grenoble et amàco

Environmental-Clay-based Concrete

International audienceThe C2D2-Environmental-Clay-based Concrete research program, funded by the French Ministry of Ecology for three years, brought together eight partners: research laboratories , material producers, constructors, technical center and educational experimentation center. The challenge was to propose innovative solutions to transform raw earth, a complex and highly variable raw material, into genuine environmental clay-based concretes whose implementation and final properties are controlled. Research has focused on cement concrete and industrial ceramics technology transfer towards a clay-based concrete: the control of granulometry, the use of dispersants and superplasticizers, coagulation techniques to harden the material and enable a rapid removal of the formwork. Exciting developments have been made, like the understanding of the impact of dispersants on the microstructure and final properties of the material. The economic partners had the ambition to commercialize innovative products. A fluid clay-based concrete was formulated from argilo-calcareous fines derived from aggregate washing; an abundant resource so far unused. This clay-based concrete was recently implemented on two construction sites, produced in a batching plant, transported in a mixer truck, poured and vibrated like a cement concrete. This is one of the pioneer experiences in France for an earth-based concrete

Environmental-Clay-based Concrete

International audienceThe C2D2-Environmental-Clay-based Concrete research program, funded by the French Ministry of Ecology for three years, brought together eight partners: research laboratories , material producers, constructors, technical center and educational experimentation center. The challenge was to propose innovative solutions to transform raw earth, a complex and highly variable raw material, into genuine environmental clay-based concretes whose implementation and final properties are controlled. Research has focused on cement concrete and industrial ceramics technology transfer towards a clay-based concrete: the control of granulometry, the use of dispersants and superplasticizers, coagulation techniques to harden the material and enable a rapid removal of the formwork. Exciting developments have been made, like the understanding of the impact of dispersants on the microstructure and final properties of the material. The economic partners had the ambition to commercialize innovative products. A fluid clay-based concrete was formulated from argilo-calcareous fines derived from aggregate washing; an abundant resource so far unused. This clay-based concrete was recently implemented on two construction sites, produced in a batching plant, transported in a mixer truck, poured and vibrated like a cement concrete. This is one of the pioneer experiences in France for an earth-based concrete