Camille Magniont

Plant aggregates and fibers in earth construction materials: A review

Abstract Earth as a building material is increasingly being studied for its low environmental impact and its availability. Plant aggregates and fibers have been incorporated into the earth matrix in the aim of enhancing performance for thousands of years but scientific studies began quite recently. The present paper reviews the state of the art of research on the influence of these various natural and renewable resources in unfired earth materials such as compressed earth blocks, plasters, and extruded and stabilized blocks. This review, based on 50 major studies, includes characterization of the particles and treatments, and recapitulative tables of the material compositions, and the physical, mechanical, hygrothermal and durability performances of earth-based materials. A lack of references on hygroscopic and durability properties was observed. Future research orientations are thus suggested to promote and develop this type of sustainable material, which provides a solution for saving energy and natural resources.

Use of plant aggregates in building ecomaterials

The aim of this paper is to compare hemp shiv and sunflower pith properties when they are used as plant aggregates incorporated into a pozzolanic matrix. Scanning electron microscope observation of these aggregates showed distinct microstructures, which could be responsible for the differences in mechanical and thermal behaviour observed between composites including these two types of plant aggregates. The long-term behaviour of composites revealed the mineralization of plant aggregates, in particular hemp shiv, by calcium compounds. L’objectif de cet article est de comparer les propriétés de la chènevotte du chanvre et de la moelle de tournesol dans le cadre de leur valorisation en tant que granulats végétaux associés à une matrice pouzzolanique. L’observation par microscopie électronique à balayage de ces granulats a permis de mettre en évidence leurs microstructures distinctes. Ceci expliquerait les écarts de comportement mécanique et thermique des composites incorporant ces granulats végétaux. Concernant le comportement a long terme des composites, les résultats mettent en évidence la minéralisation des particules et en particulier de la chènevotte par des composés de nature calcique.

Effect of Plant Aggregates On Mechanical Properties Of earth bricks

AbstractA building material is mainly characterized by its mechanical performance, which provides proof of its quality. However, the measurement of the compressive or flexural strength of an earth-...

Flax and hemp fibre reinforced pozzolanic matrix: evaluation of impact of time and natural weathering

Environmental issues have led to new research into the development of eco-friendly materials. For building materials, plant fibre reinforced matrix is one of the rising innovative solutions. In this paper, the benefits of reinforcing a pozzolanic matrix with flax and hemp fibres and the impact of time and environmental conditions are presented. The mechanical behaviour of the composites was studied in a bending test over 1 year. Two exposure conditions were studied: controlled conditions and natural outdoor weathering. SEM observation coupled with EDS analysis was used to complete the results with the physicochemical interaction between plant fibres and the mineral matrix.

Evaluation of Hemp Concrete Thermal Properties

Nowadays, the need for reducing energy consumption, environmental impacts of building highlights the benefits of bio-based building materials such as hemp concrete. Indeed, hemp is a renewable resource which stores CO2, one of the main greenhouse gas. Moreover, the porous structure of hemp concrete would lead to a typical hygrothermal behaviour allowing good thermal insulation, potential hygrothermal comfort regulation. A previous study carried out in Laboratoire Matériaux et Durabilité des Constructions de Toulouse (LMDC) laboratory led to the development of an innovative pozzolanic binder associated with hemp shiv to design a precast block for wall construction. The present work aims at measuring the thermal properties of precast hemp concrete. Heat capacity is assessed through effusivity measurement, differential scanning calorimetry method (DSC) on the separate components while thermal conductivity measurements are carried out with both guarded hot plate method, hot wire method. The assessment of the thermal conductivity of hemp concrete for increasing water contents is also performed with this latter method. These data are required inputs for numerical model developed in the second part of this project.