Environmental Engineering Reference
In-Depth Information
natural stone from the azores archipelago: Relationship between
lithology and physical-mechanical behaviour
João B.P. silva
Research Unit Geobiotec, FCT, Universidade de Aveiro, Aveiro, Portugal
cristina carvalho
LNEG (National Laboratory for Energy and Geology), U.C.T.M. - Lab, Infesta de Mamede, Portugal
sérgio Diogo caetano
ARENA (Regional Agency for Energy and Environment of the Azores Autonomous Region),
São Miguel, Portugal
celso Gomes
Research Unit Geobiotec, FCT, Universidade de Aveiro, Aveiro, Portugal
aBsTRacT: since the early days of the settlement in the azores archipelago, in the 15th century, natural
stone has been used in the construction of residences, religious monuments and public buildings, because
of its local abundance. The purpose of this study was the characterization of the main commercial types
of natural stone of the archipelago of azores, in terms of their petrographic, mineralogical, chemical
and physico-mechanical properties. This characterization allowed the appraisal of their suitability for
the different types of applications. in a preliminary stage, the study comprised seven varieties of natural
stones exploited in severals quarries and processing plants of são Miguel island and santa Maria
island—two of the nine islands that form the azores archipelago. Petrographic studies and chemical
analysis were performed in all the selected varieties as well as the following physical-mechanical tests
(carried out according to european standards): uniaxial compressive strength, flexural strength under
concentrated load, apparent density, water absorption at atmospheric pressure, open porosity (or appar-
ent porosity), linear thermal expansion coefficient, abrasion resistance (with capon machine) and rupture
energy (commonly known as impact resistance). Finally, relationships were established between the main
physical-mechanical properties of the natural stones under study, and their main lithological and textural
characteristics.
1
inTRoDUcTion
the construction industry, putting in perspective
the establishment of quality criteria, both in the
resource exploitation and in the resource use.
since the beginning of the azores archipelago
settlement in the 15th century, lavic and pyroclastic
volcanic stones, both common in this archipelago,
are important mineral resources used for the
construction of houses, monuments and public
works, among other applications.
on this work seven rock types of natural stone
were studied. The selection criteria were based upon
its representativeness, and also on the fact of being
widely used, both in quality and in quantity on the
islands of são Miguel (5) and santa Maria (2). in
azores arquipelago there is a trade and popular
nomenclature used to characterize natural stone
which comprises hardness, cohesion, mechanical
on a national range, natural stone is a resource
whose current importance, in economical terms,
has been accompanied by growing scientific and
technological knowledge (Moura, 1991, costa
et al
., 1995).
on a regional scale, regarding azores archi-
pelago, extracting, manufacturing and trading
natural stone industries on são Miguel island,
and to a lesser extent on santa Maria island, have
great social, cultural and economical interest for
their communities, whose demand for local raw
materials has grown in recent years.
The study of the main physical, chemical
and technological properties of natural stone is
designed to optimize the use of this resource in
