Life cycle analysis of environmental impacts of earthen materials in the Portuguese context: Rammed earth and compressed earth blocks

Abstract

Keywords:Vernacular architecture Life-cycle assessment Environmental impacts Rammed earth Compressed earth block (CEB) Earthen architecture a b s t r a c tIn the Portuguese context, the life cycle assessment of building materials is still in its infancy. So far, there is only a small number of Environmental Product Declarations (EPDs) available, all target for industriallybased materials. Although vernacular earthen materials are seen as ecological materials, with low potential environmental impacts, there are no studies that allow to quantitatively compare these materials with conventional ones, according to the applicable standards. In the case of Portugal, there are no EPDs or studies for these materials and the studies available worldwide are hard to compare, since they not follow the same life-cycle assessment methodology. This paper aims at contributing to a better understanding about the environmental performance of earthen materials by presenting results from the life cycle assessment of Compressed Earth Blocks (CEBs) and Rammed earth, based on specific life cycle inventory values obtained from a producer company, following the guidance provided by the standard EN15804. Among other conclusions, results show that CEB and Rammed earth have a total Embodied Energy of 3.94 MJ/block and 596 MJ/1 m 3 and a Global Warming Potential of 0.39 kg CO 2 eq/block and 47.5 kg CO 2 eq./1 m 3 , respectively. In a cradle-to-gate analysis of different walls, the use of earthen building elements can result in reducing the potential environmental impacts in about 50%, when compared to the use of conventional ones. Additionally, the advantages of using earthen materials are also discussed for the different building life-cycle stages, focusing on the possibility to recycle these materials in a closed-loop approach.

The Potential of CEB Reinforced Masonry Technology for (Re)construction in the Context of Disasters

“…However, Fernandes et al [ 56 ] highlight the lack of studies that allow the precise quantification of the environmental impacts associated with the earth use at the expense of conventional materials, according to the applicable rules in force. This fact can be justified by the heterogeneity of the soil properties according to the extraction site, its small-scale production and the consequent difficulty in normalizing its use.…”

Rammed Earth Construction: A Proposal for a Statistical Quality Control in the Execution Process

“…In cases dealing with prismatic molds, a 15 cm cube (sample A) should be obtained for computing the variable CS and one of at least 5 cm high (sample B) for determining some physical properties (like real and D, and P). Note: 1 Carry out the test if the origin or nature has changed with respect to tests done before the execution process. 2 Keep the stockpile isolated from moisture variations.…”

“…Heritage values, bioconstruction, and sustainability are three factors closely related to rammed earth buildings, which make it an advantageous construction technique that should be preserved and adapted to modern times. Moreover, the low environmental impact of its life cycle assessment makes this technique useful for the development of a more sustainable building sector [1][2][3]. In spite of this, there are some important obstacles to achieving the full potential of building with rammed earth.…”

Mechanical and Thermal Performance Characterisation of Compressed Earth Blocks

“…Earth has been used as a building material since ancient times in several different ways around the world [1][2][3][4]. Industrialised building systems and the dissemination of materials, like concrete [5], have replaced earthen construction.…”

“…Industrialised building systems and the dissemination of materials, like concrete [5], have replaced earthen construction. Today, earthen construction is associated with poverty [2], and most of this type of construction is located in developing countries. The continuous increase in the energy cost of some building materials (cement and ceramic bricks) and environmental issues are promoting the use of sustainable materials, such as the earthen materials known by their abundance and low-cost production [5][6][7].…”