Building decarbonization by means of ancient techniques. Assessment of environmental impact, energy performance and mechanical safety

Abstract

The construction sector seeks for more environmentally friendly construction materials. Henceforth, materials such as earth-based materials (EBM) or straw bales (SB) are lately becoming more popular for architectural designs. Notwithstanding, their technical aptitudes are major concerns since few studies have assessed them from an integral perspective. Thus, this article aims to assess their performance by considering different approaches such as energy consumption, thermal comfort, mechanical response, and environmental impact. Results were compared to those provided by conventional materials such as fired bricks and concrete blocks. A typical detached house was modelled by following Chilean building codes. The energy assessment was determined by dynamic calculations while mechanical aptitude was assessed by means of push-over analysis. Finally, the environmental impact in a cradle-to-grave perspective was determined through the ReCiPe methodology. Results show that EBMs and SB significantly reduce the environmental impact when compared with traditional materials. Thus, for human health, resource depletion and ecosystem quality an average of 40, 30 and 20%, respectively, were obtained by choosing SB or EBM. Since all cases did accomplish thermal insulation requirements, no significant differences were found in energy consumption. However, the higher thermal capacity of EBMs and the higher thermal resistance of SB, certainly led to savings (approx. 5%). Finally, for a medium intensity earthquake, negligible damage may be expected, and immediate occupancy levels are showed from capacity curves. It is concluded that EBMs and SB significantly reduce the environmental impact of the building and lead to satisfactory results in terms of energy performance and mechanical aptitude.