Influence of particle grading on the hygromechanical properties of hypercompacted earth

Abstract

Civil engineering research is increasingly focusing on the development of sustainable and energy-efficient building materials. Among these materials, raw (unfired) earth constitutes a promising option for reducing the environmental impact of buildings over their entire service life from construction to demolition. Raw earth has been used since old times but only recently has acquired prominence in mainstream building practice. This is mainly because of the development of novel methods to enhance the mechanical, hygroscopic and durability properties of compacted earth without increasing carbon and energy footprints. In this context, the present paper studies the dependency of the strength, stiffness, moisture capacity and water durability of compacted earth on particle grading. Results indicate that the particle size distribution is a key variable in defining the hygromechanical characteristics of compacted earth. The effect of the particle size distribution on the hygromechanical properties of compacted earth may be as important as that of dry density or stabilisation. This study suggests that a fine and well-graded earth mix exhibits higher levels of strength, stiffness, moisture capacity and water durability than a coarse and poorly-graded one.

Experimental study on the capillary absorption characteristics of rammed earth

“…The bulk density of the materials is determined by means of 70 °C convection oven drying for the dry mass and immersion in mercury for the volume, since water is destructive [19]. This is performed as part of the mercury intrusion porosimetry test procedure and hence small samples are used.…”

Influence of Particle Size on Compressed Earth Blocks Properties and Strategies for Enhanced Performance

“…Regarding mechanical and durability properties, the results in the current literature are not confirmed. Blocks made from finer soil particles are not stronger or more durable [8][9][10]. However, results are not fully comparable as the mentioned studies either add sand or reconstitute the soil, leading to a substantial change in the natural state of the soil.…”

Hydromechanical behaviour of two unsaturated silts: laboratory data and model predictions

“…A thorough understanding of coarser soils is, however, important as these materials are commonly encountered in geotechnical works (e.g. dams, embankments) and widely used in earth building (Bruno et al, 2017;Cuccurullo et al, 2018). This paper contributes to the investigation of the unsaturated behaviour of coarser soils by testing two different silts under isotropic conditions inside triaxial cells along a variety of stress paths that include: a) increase/decrease of mean net stress at constant suction, b) increase/decrease of suction at constant mean net stress and c) increase of mean net stress at constant water content with the simultaneous measurement of suction.…”