ADOBE BRICK AS A STRUCTURAL MATERIAL. PERSPECTIVE APPLICATIONS TO VAULTS

1. Introduction
In the present work some results concerning uniaxial compression tests on sun-dried earth bricks are reported. The outcome of our experimental campaign, conducted in the Laboratory of Structural Mechanics of the University of Salerno, though limited to a small number of specimens, encourages to employ adobe bricks as a structural material. This conclusion is supported also by the vast experimental evidence supplied by other researchers in recent years (see Lenci [4] and references therein).
Buildings made of sun-dried earth had been in use for several thousand years and still represent a realistic and competitive option for the realization of new constructions, due to their high sustainability often coupled with the ease in the supply of the raw material. Though scarcely stiff and strong, in our tests we detected a relevant apparent ductility (due to friction) in compression. A sensible dosage of straw has shown crucial to maximise strength and ductility.
The moderate strength in compression and the very low tensile strength of the adobe bricks (a common feature also for other kinds of masonry materials, such as tuff or limestone) suggests structural applications in compressed elements under low stress, such as walls of buildings of 1-3 storeys, arches and vaults of limited span. Here we analyse the stress state in a masonry vault of small span (4-5 m), modelled as a no- tension membrane, adequately sustained at the boundary, under vertical loads. On designing accurately the geometry of the vault and the adobe brick pattern and disposition, such type of structure would allow to build up floors for housing, without the necessity of formworks or centrings. […]