In the past decade, there has been an increase in the environmental performance assessment in earth construction through the life cycle assessment (LCA) methodology. A Systematic Literature Review verified LCA methodology trends of five earth construction techniques from 2016 to April 2022, resulting in 27 studies. The results have been analyzed through qualitative thematic analysis, considering LCA methodology. Considering embodied carbon (GWP) and embodied energy, transportation and binder content were the main factors that influenced environmental performance. Hence, earth-based constructions exhibit better results in different impact categories than conventional materials. Environmental guidelines and technical features that were presented in the LCA studies are discussed for Adobe, Cob, Rammed Earth (RE), Compressed Earth Block (CEB), and Light Straw Clay (LSC). This study presents environmental benchmarks at the unit, wall, and building scales aiming to encourage LCA methodology applied to earth construction techniques and fostering the discussion of earth construction sustainability.

Biomaterials and raw earth have demonstrated a promising potential for improving various thermal properties of plastering mortars used in buildings. The objective of this research was the evaluation of the thermal-energy performances and life cycle greenhouse gas (GHG) emissions of different mixtures of engineered, bio-based earth mortars composed of bamboo particles, earth, and different cementitious materials. Four mixtures were assessed: mortars without bamboo particles (matrix), and mortars containing 3%, 6%, or 9% of bamboo particles by volume. The bulk density and thermal conductivity values obtained for the matrix and mortars with the highest percentage of bamboo particles (9%) were 1704.13 and 1471.80 kg/m³, and 0.62 and 0.43 W/M·K, respectively. Based on experimental results, thermal-energy simulations were carried out using a social housing project as a case study. The simulations evaluated different climate conditions and applied life cycle GHG emissions assessment methodology. Compared with typical cement and lime plastering mortars, the proposed bio-based earth mortars presented a superior thermal-energy performance and lower GHG emissions, particularly the 9% bamboo particles mixture. GHG emissions reached a maximum decrease of 28%. The main scientific contribution of this research is the presentation of an engineered, bio-based earth mortar that can be manufactured using local raw materials available in most developing countries with significant housing demands. The method used, based on experimental research, thermal-energy analysis, and life cycle GHG emissions, may be used for evaluating other innovative materials. It was verified that even with thin plastering in buildings, it is possible to achieve energy efficiency gains and to reduce GHG emissions.

Foram avaliados os potenciais impactos ambientais associados a diferentes argamassas de terra sem e com estabilizantes químicos (cal hidratada e cimento Portland) e tais impactos foram comparados com aqueles apresentados pelas argamassas convencionais de cimento, cal e areia. Foi utilizada a metodologia de Avaliação do Ciclo de Vida (ACV), com o escopo do berço ao túmulo. Foram avaliadas quatro categorias de dano: Mudanças Climáticas, Saúde Humana, Qualidade dos Ecossistemas e Depleção de Recursos foram avaliadas. Os ligantes químicos constituíram os insumos mais impactantes para a produção de argamassas de terra estabilizada, quando a ênfase foi o desempenho ambiental. A vida útil do revestimento e o transporte da terra influenciaram significativamente as categorias de Saúde Humana e Qualidade do Ecossistema. Os revestimentos de terra, mesmo quando estabilizados, podem ter ganhos ambientais de até 80% para a categoria de Mudanças Climáticas, caso tenham a mesma vida útil que revestimentos convencionais. Portanto, esses revestimentos baseados em terra crua podem constituir uma alternativa com grande potencial ambiental para mitigação dos impactos associados aos revestimentos comumente aplicados nas edificações. Ressalta-se, entretanto, a necessidade de serem adequadamente especificados na etapa de projeto, assim como de utilizarem, sempre que possível, a terra disponível localmente.

In continental countries, building materials are often moved over long distances from factories to building sites. This is especially important when quality and performance certification systems are required for the building materials’ acquisition. In this scenario, the transportation phase tends to have a great contribution to building materials’ environmental impacts. Taking into consideration that countries such as China, India, and Brazil, i.e., continental countries, are expecting the largest future housing demand, the issue of transportation will have a crucial role in environmental impacts. Through a Brazilian case study, the present work investigates the potential environmental impacts of structural masonry made of concrete and ceramic blocks certified by the Brazilian Quality Program. A cradle-to-site Life-Cycle Assessment (LCA) is carried out while considering a country-level approach using data from the literature and Ecoinvent. The results show that ceramic blocks are preferable for most states and scenarios. Human Health and Ecosystem Quality are the two categories most affected by transportation, and they can reach more than 96% and 99%, respectively. The efficiency of the building material transportation system plays an important role in reducing greenhouse gas emissions. A shift in building components from concrete to ceramic blocks has the potential to mitigate between 154 and 229 Mt CO2-eq between 2020 and 2050. The methodological approach used in this work can be applied to other building materials and other countries, especially those of continental dimensions that are expected to have a significant future housing demand.