Presence of asbestiform minerals in lightweight concretes. Their environmental impact
View/ Open
Date
2015Author
Lescano, Leticia
Marfil, Silvina A.
Maiza, Pedro J.
Sfragulla, Jorge A.
Bonalumi, Aldo A.
Metadata
Show full item recordAbstract
Lightweight concrete has a lower unit weight than conventional concrete and a high
thermal insulation capacity. It is manufactured with either natural or artificial lightweight
aggregates. Vermiculite, one of the natural lightweight aggregates used, is a micaceous
material that when heated increases its original volume due to an exfoliation process, so its
incorporation in concrete or mortar imparts very low density. These natural materials usually
contain impurities such as asbestiform minerals that can be released during the expansion
process, causing a harmful environmental effect. Commercial asbestos-containing materials
are currently banned due to the asbestos-related lung diseases they cause.
In the province of Córdoba, Argentina, there are vermiculite mines where impurities such
as asbestos group minerals have been identified. Studies using stereomicroscope, petrographic
microscope, XRD, SEM, DTA and chemical analyses were conducted to characterize the
different types of asbestos present and determine their particle size to assess whether they
could be harmful to human health. Mica group minerals, abundant quartz and amphiboles
were identified. The latter occur as isolated green crystals and their average length is 900 µm.
Tremolite was determined by XRD.
The aim of the present work is to reveal the presence of these minerals and warn about
their use and disposal at the end of the useful service life of the work.