Introduction of vegetal particles into an insulating mineral foam for building application

Abstract Building insulation is currently one of the biggest challenges to reduce energy consumption and by extension the human impact on Environment. In order to reduce this impact, the manufacturing of the building materials is of importance. This paper investigates the feasibility of incorporating vegetal particles into a low carbon mineral foam and evaluates their influence on the fresh and hardened properties relevant for building insulation applications. The insulating foam, made of lime, sulfo aluminous cement, and limestone clay fine, is produced by a direct foaming method and aims at having a thermal conductivity lower 0.065 W/m/K combined with a compressive strength higher than 0.2 MPa. Therefore, in this research, vegetal particles of hemp, flax and miscanthus were added in order to evaluate the feasibility of such a mixture and determine their impacts on the mineral foam. Plant-based particles, as in vegetal concretes, tend to decrease mechanical strength but allow similar foamability. In addition, mineral foam with vegetal particles exhibits better hygroscopic properties (+ 28% of moisture buffer value and between 35% and 74% of water permeability). The main benefit of the inclusion of vegetal particles is environmental, in fact, incorporating hemp shives reduced the carbon footprint by more than 35%. Hightlights. • Thermal conductivity of the studied foams reaches until 0.053 W/m/K; • An excellent moisture buffer value is achieved (average: 2.07 g/(m²·%RH)); • A foam was designed with a carbon footprint of 10.63 KgCO 2 eq/m 3 .