Chiara Turco (a) https://orcid.org/0000-0003-4686-0578
Elisabete Teixeira (a) https://orcid.org/0000-0003-1435-0733
Ricardo Mateus (a) https://orcid.org/0000-0003-2973-8175

a University of Minho, ISISE, ARISE, Department of Civil Engineering, Guimarães, Portugal

ABSTRACT

Compressed earth blocks (CEBs) are increasingly regarded as a low-impact alternative to masonry construction, given their local availability, low processing energy and favourable hygrothermal behaviour. To meet contemporary structural and durability requirements, hydraulic binders such as lime or cement are often used to stabilise the earth. However, the implications of such stabilisation extend beyond functional performance and remain insufficiently addressed from an environmental and circularity perspective. This paper presents the functional characteristics and an assessment of the environmental performance of CEBs stabilised with natural hydraulic lime (NHL), with the aim of establishing a benchmark for modern earth masonry. Mechanical strength, thermophysical behaviour and durability-related properties are synthesised from previously published experimental studies, whilst environmental performance is assessed through a life cycle analysis. The results indicate that the performance benefits associated with stabilisation using NHL are accompanied by a non-negligible increase in embodied environmental impacts. Moreover, further experimental evidence shows that NHL-stabilisation significantly compromises the reusability of earth by inhibiting clay activity, thereby limiting its potential for circular reuse. The findings highlight that, while technically effective, CEBs stabilisation with NHL constitutes a trade-off solution whose use should be contextualised and carefully justified. The paper concludes by discussing the implications of such a trade-off for sustainable masonry design and outlines future research directions towards alternative stabilisation strategies, including bio-based binders, that may reconcile performance requirements with circularity objectives.

Keywords: earthen construction; stabilisation; life cycle assessment; environmental impacts; circular economy; reusability; sustainable masonry.