Work

On the determination of characteristic compressive strength of unstabilised earth masonry using Eurocode-based methods

Year: 2026

Type: article

Abstract: Unstabilised earth masonry offers major environmental advantages due to its very low embodied energy, full recyclability, and minimal processing requirements. However, current structural design codes, such as Eurocode 6, were developed for fired clay or concrete masonry and cannot be directly applied to raw earth construction. This study investigates whether the Eurocode 6 empirical formulation for the characteristic compressive strength f k can be meaningfully adapted to unstabilised earth masonry. An experimental programme was conducted on four types of earth blocks: extruded earth blocks, artisanal and industrial compressed earth blocks, and hand-moulded adobes. Tests were performed on mortars, individual blocks, masonry couplets, and wallets, in compliance with the relevant standards. The results show that the compressive behaviour of unstabilised earth masonry is strongly governed by the block-mortar interface. Significant variability was observed between masonry types, with compressive strength differences exceeding 50% between references manufactured using different earth materials and production techniques. Attempts to adapt the Eurocode 6 empirical formulation to the four masonry references demonstrate that no single set of coefficients can consistently represent all configurations, as each calibration favours some block types while misrepresenting others. This highlights the intrinsic variability of block-mortar interactions and the limitations of a unified empirical formulation. Two alternative pathways for determining f k are identified: adapting Eurocode 6 using block-specific coefficients, or applying the Eurocode 0 statistical fractile method directly to test data. While the former requires extensive harmonised testing, the latter follows a performance-based approach and could be made more practical if masonry couplets are confirmed as reliable predictors of wallet strength.

Source: Construction and Building Materials

DOI: 10.1016/j.conbuildmat.2026.145439

Authors: Mathias Favier, Florent Vieux-Champagne, Pascal Maillard, Eugénie Crété, Ines Touzard

Institutions: Sols, Solides, Structures, Risques, Université Grenoble Alpes, École Nationale Supérieure d'Architecture de Grenoble

Language: English

Topic: Hygrothermal properties of building materials

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,540

Funder: Agence de la transition écologique