Environmental Engineering Reference
In-Depth Information
Table 1. Results from tests made on Madeira, azores
and canary islands samples.
in the first case, they are finer, with slightly bigger
specific weights as well as maximum dry density.
cBR values presents a wider range than the
azorean ones.
Though it's possible to take some conclusions
with the existing data, it's necessary to proceed
the investigation with the execution of more tests
to understand better the geotechnical behavior of
these materials in order to improve their applica-
tions in civil engineering works.
Tests
Units
Madeira
azores
canarias*
specific Weight
kn/m
3
25-29
20-22
23-25
In situ
Dry
Density
kn/m
3
12-14
-
8-15
Maximum Dry
Density
kn/m
3
14-17
12-14
-
cBR
%
40-96
42-73
-
Friction angle
º
29-50
-
30-45
cohesion
MPa
0-0.1
-
0-0.1
aknoWleDGeMenTs
* Gonzalez Vallejo et al., 2007.
Most of the tests presented in this paper were made
in lRec Madeira and lRec azores to whom
we are grateful. We also would like to thank Prof.
Maria de lurdes lopes, Prof. castorina Vieira and
Master Rui silvano, from Faculty of engineering
of the University of Porto, for the support given in
the execution of tests in big dimension shear box.
4
soMe aPPlicaTions oF BasalTic
PYRoclasTic Rocks on ciVil
enGineeRinG WoRks
as volcanic scoria are plentiful in the azores,
specially in s. Miguel island, and due to its geo-
technical characteristics, they assume particular
importance because of its use in different kinds of
civil engineering works.
one of the uses of this material is in the execu-
tion of landfill (improvement of the soil founda-
tions, landfills on roads, etc), and they can be used
in any part of these.
Because scoria is very hard and porous, it makes
a good base for roads.
They have been used traditionally as a material
for pavement layers of roads, as well as used
in pavement beds, and for the improvement of
excavation areas. in most cases it is used only as sub-
base layer, but sometimes as base and wear coarse
layer in roads with little traffic (Fraga 1988).
in both these applications, once its grain size
distribution suffers changes by particles breakage
and crush, particularly when compacted, the control
of this material in civil engineering works should
only be executed considering the grain size distribu-
tion that the materials shows after compaction.
The industry of making masonry bricks also
uses volcanic scoria as row material.
crushed and screened to specific sizes, the
open structure and excellent drainage properties
of volcanic scoria creates a truly versatile product
for both landscaping purposes and as a bedding
material for under soil drainage applications, and
behind retaining walls.
ReFeRences
asTM D2487-06e1 standard Practice for classification of
soils for engineering Purposes (Unified soil classification
system), in
Book of Standards Volume: 04.08, Soil and
Rock
, asTM international, W. conshohochen, Pa. asTM
international.
cas, R. & Wright, J. 1987.
Volcanic Succes
sions. london:
ed. allen & Unwin.
Fraga, c. 1988.
Caracterização Geotécnica de Escórias
Vulcânicas
. Master Thesis. Univ. nova de lisboa,
146 p.
Fraga, c. 2009. especificações Técnicas para aplicação de
Bagacinas em sub-bases de Pavimentos Rodoviários.
nT 88/2009, 17 p, lRec, P. Delgada.
lnec e 237 1970. agregados. ensaio de Desgaste pela
Máquina de los angeles. lisboa: lnec.
MacDonald, G. 1972.
Volcanoes
. new Jersey: Prentice-
hall.
scmincke, h. 2006. Volcanism, Berlin: springer.
serrano, a., olalla, c., Perucho, a. & hernandez-Gutierrez,
l. 2007.
Strength and deformability of low density
pyroclasts
. in a. Malheiro & J.nunes (eds),
Volcanic
Rocks
: 35-43. london, Taylor & Francis/Balkema.
Vallejo, l., hijazo, T., Ferrer, M. & seisdedos, J. 2006.
Caracterización geomecánica de los materiales
volcánicos de Tenerife
—Madrid. ed. Vallejo e Ferrer,
instituto Geológico y Minero de españa.
Vallejo, l., hijazo, T., Ferrer, M. & seisdedos, J. 2007.
Geomechnical characterization of volcanic materials in
Tenerife
. in a. Malheiro & J. nunes (eds),
Volcanic
Rocks
: 21-28. london, Taylor & Francis/Balkema.
5
conclUsiVe ReMaRks
as it was possible to see by the results presented in
this chapter, there are several similarities between
the Madeira and the azores basaltic pyroclasts.
