An overview of the remaining challenges of the RILEM TC 274-TCE, testing and characterisation of earth-based building materials and elements

Abstract

Based on the RILEM Technical Committee 274-TCE work, this paper is a discussion of the remaining engineering challenges faced by earthen architecture. The assessment of earth material performances requires the development of appropriate procedures and standards. This is discussed in particular for the characterisation, hygrothermal behaviour, mechanical behaviour, and durability of earth materials. One other important challenge, since one of the main advantages classically put forward, is its ecological performance, is a proper assessment of life cycle assessment of earth materials, elements and buildings. Moreover, the paper develops why the approach to earthen construction must be different compared to the dominant construction materials, to preserve its ability to contribute to the ecological transition in the construction sector. In particular, the needs of using local soils, with an architectural approach coping with the limits of the materials, and developing an architectural optimisation to preserve the earthen materials multifunctionality rather than selecting a sole property to be maximised. Lastly, the findings of the paper can be used to develop a holistic approach to earthen construction to foster the development of new earthen architecture projects.

Experimental Characterization of Raw Earth Properties for Modeling Their Hygrothermal Behavior

“…To the best of our knowledge, except for the few studies presented above, cob building is not well described in the literature [18]. This leads to its low use in current construction.…”

Recyclable and Efficient Construction using Mineral Landfill Materials and Demolition Wastes

“…The earthen building materials not yet covered by DIN standards are regulated in the Lehmbau Regeln [30]. At the international level, similar standards are under development [31][32][33][34][35][36]. However, although structures made of CMM are built worldwide [37], there is still a considerable lack of uniform specifications and regulations both for the suitability testing of the materials used and for quality monitoring [38,39].…”

Challenges to upscale earth block masonry in Western Europe from a life cycle perspective

“…Most scientific articles related to earth construction and earth block masonry address its technical barriers [13,20]. From a life cycle perspective, these occur mainly during the extraction, production, construction and use phases.…”

“…Since the end of last century, the development of normative documents for different earthen construction techniques has emerged worldwide. Nevertheless, the lack of standards is generally cited as the primary technical barrier [8,12]. According to the RILEM on the standardisation of earth construction on a European scale, creating new codes and standards is essential to encourage designers to build with earth and to persuade regulatory bodies [12].…”

“…Regarding the design, construction and use phases of earth block masonry infill walls (EBMIWs), the lack of standards is considered an urgent challenge by all manufacturers. Indeed, a lack of coherence among standards forces designers to fend for themselves in obtaining building approvals [12]. Additionally, technical data on technical performance, such as hygrothermal behaviour, is lacking to support the manufacturer's claims of reduced energy demands for HVAC.…”