Experimental characterization of italian adobe bricks reinforced with straw fibres

Recent reports have estimated that a large amount of the world’s population lives in earthen constructions, including adobe masonry (AM) buildings. The latter are located in both least developed and industrialised countries, where adobe construction techniques are also used for new dwellings. This is motivated by the need of ensuring comfort to occupants, architectural compatibility with historical built environments, and sustainability. In Italy, AM buildings are present in many regions with low-to-medium seismicity. This paper presents the experimental characterization of straw fibre reinforced adobe bricks typically used in Sardinia, the second biggest island (besides Sicily) in the Mediterranean Sea. First of all, both diameter and length of straw fibres were statistically characterised. Displacement-controlled compression and three-point bending tests were then carried out on cubic and prismatic specimens, respectively. In both cases, stress–strain models and statistics of the main mechanical properties were derived for design/assessment purposes. Processing compression test results allowed the authors to derive the correlation between compressive Young’s modulus and peak compressive strength. Linear and non-linear regression models were fitted to experimental data to allow the prediction of compressive fracture energy as a function of peak compressive strength. Finally, bending tests led to estimate the tensile Young’s modulus through a homogenised beam theory approach based on the assumption of bi-modulus earthen material