Life cycle assessment of a hemp concrete wall: Impact of thickness and coating

Abstract

In a context of sustainable development and energy sparing, a life cycle assessment (LCA) may be useful to make good choices. Thus, this study concerns the LCA of an environmentally friendly material used for building construction, hemp concrete. The functional unit is first defined per square such that the wall may provide the function of bearing wall meter and its thermal performance is described by a thermal resistance of 2.78 m².K/W. The results then showed that the production phase of raw materials is mainly responsible for the environmental impact of the wall, mostly due to the binder production. It was also shown that, compared to traditional construction materials, hemp concrete has a low impact on environment. Moreover, hemp concrete contributes to reduce climate change as photosynthesis-mediated carbon sequestration and carbonation serve to reduce atmospheric carbon dioxide. A sensitivity analysis is performed on three criteria: wall thickness, renewal of coatings and compounds of the indoor coating.Our results show that environmental indicators evolve with wall thickness, except for the climate change indicator. It improves with thickness due to carbon sequestration and carbonation. Moreover the increase in the wall's thermal resistance with wall thickness is not taken into account in such an LCA performed at the material level. The renewal of coating slightly impacts the environmental indicator for small numbers of renewals but it leads to negative effects if they are too numerous. It appears that hemp-lime coating has a greater impact than sand-lime coating as it embeds more binder.

Moisture buffer potential of experimental wall assemblies incorporating formulated hemp-lime

“…The aim of the present study is to compare the moisture buffer values of vapour-open wall assemblies containing hemplime and inner linings and surface treatments with that of the exposed hemp-lime. The Nordtest [9] protocol is followed to determine the moisture buffer values of the assembly. The experiments described in this article are part of the experiments being carried out in the EPSRC-funded HIVE building situated in the Building Research Park at Wroughton, UK.…”

“…Hemp shiv comes from renewable sources and lime is a flexible, reusable and breathable material with significantly lower embodied energy than conventional masonry materials [4]. Because of its low compressive strength [5e8], hemplime is typically used as an insulating infill material between structural framework [9].…”

Physical and mechanical properties of composites based on hemp shives and lime

“…According to Rahim's research [5] composites porosity was comparable -hemp composite with apparent density of 478 kg/m 3 indicated total porosity equal to 76.4% and rape straw composite with apparent density of 487 kg/m 3 indicated total porosity equal to 75.1% . Other research [8] has presented that composite revealed total porosity of 79% with the apparent densities of 430-460 kg/m 3 .…”

Towards regenerative and positive impact architecture: A comparison of two net zero energy buildings

“…With respect to Cole who stated the scarcity to find similar built projects can show the capability of expanding our environmental performance targets (Cole, 2012;Waldron, Cayuela, & Miller, 2013;Wolpensinger & nachhaltiges Bauen, 2016). This study is in line environmental assessments made for plant based construction materials (Van der Lugt, 2008;Prétot, Collet, & Garnier, 2014;Ip & Miller, 2012;Wolpensinger & nachhaltiges Bauen, 2016;Waugh, Wells, & Lindegar, 2010). Despite the small sample of case studies, the author tried to go into buildings with a well-defined focus and to collect specific building performance data systematically.…”