Experimental Investigation on the Influence of Partial Immersion and Drying Cycles on Hemp Concrete Properties

The construction sector has a significant environmental impact, since it is the largest energy consumer and is responsible for 25% of greenhouse gas emissions. Vegetal concretes represent a good alternative to reduce the environmental footprint of building materials, because of their thermal insulation properties and the use of vegetal waste. In addition, they have the outstanding environmental quality of being carbon negative. Hemp lime concrete is the most used bio-based material in building sector and its potential as an environmental-friendly material was quickly realized. It is a relatively new building material and its use is limited by the lack of data concerning its durability and the evolution of its properties over time. This paper focuses on the influence of an accelerated aging of hemp lime concrete on its hydric and thermal properties. Samples will undergo several cycles of partial immersion and drying and will be characterized before and after the accelerated aging. Partial immersion was preferred to complete immersion, as it is more representative of the real climatic conditions. The thermal conductivity and the capillary absorption coefficient will be determined. Microscopic observations of the surface topology will also be carried on, in order to evaluate the microstructure alteration.