Characterization of Barley Straw, Hemp Shiv and Corn Cob as Resources for Bioaggregate Based Building Materials

Aurélie Laborel-Préneron (1) , Camille Magniont (1) , Jean-Emmanuel Aubert (1)

1 LMDC - Laboratoire Matériaux et Durabilité des constructions

12 Expanding the use of low-environmental impact materials in the field of building materials is a 13 major aim in a context of sustainable development. These alternative materials should be 14 non-polluting, eventually recycled, and locally available. Bioresources are already used in 15 some building materials but few studies have investigated their relevance in such 16 applications. The aim of this paper is to evaluate the suitability of three kinds of vegetal 17 aggregates: barley straw, hemp shiv and corn cob. The availability of these bioresources, 18 extracted from a French database, is discussed, as are their physical properties and 19 chemical compositions. Their microstructure is described with SEM images and their particle 20 size distributions are provided through image analysis. Sorption-desorption isotherms are 21 measured by a Dynamic Vapour Sorption system. Bulk density, thermal conductivity and 22 water absorption are also quantified. The results highlight a tubular structure for the three 23 different aggregates, with low bulk density and thermal conductivity (0.044, 0.051 and 0.096 24 W.m-1 .K-1 respectively for straw, hemp shiv and corn cob) and high water absorption, 25 especially for barley straw and hemp shiv (414 and 380% vs. 123% for corn cob). Their 26 hygric regulation capacity is also sufficiently good, with a water sorption of between 20 and 27 26% at 95% of relative humidity. These plant aggregates could therefore be used as 28 additions in an earth matrix, or a hydraulic, pozzolanic, air lime or gypsum binder, or just as 29 loose-fill insulation material. However, future research should focus on their resistance to fire 30 and bacterial growth to validate this approach. 31 32

Mots clés: Barley straw; hemp shiv; corn cob; bio-based building material; avalability; properties

Domaines: Génie civil

Aurélie Laborel-Préneron, Camille Magniont, Jean-Emmanuel Aubert. Characterization of Barley Straw, Hemp Shiv and Corn Cob as Resources for Bioaggregate Based Building Materials. Waste and Biomass Valorization, 2018, 9 (7), pp.1095 - 1112. ⟨10.1007/s12649-017-9895-z⟩. ⟨hal-01876843⟩