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XXX IAHS
World Congress on Housing
Housing Construction – An Interdisciplinary Task
September 9-13, 2002, Coimbra, Portugal
Eds.: Oktay Ural, Vitor Abrantes, António Tadeu
Experimental Study of Concrete Durability Parameters produced
with Different Types of Aggregates
F. Pacheco-Torgal
Department of Civil Engineering
Polytechnic Institute of Castelo Branco, 6000-001 Castelo Branco, Portugal
e-mail: fernandotorgal@est.ipcb.pt
J.P. Castro-Gomes
Department of Civil Engineering
University of Beira Interior, 6201-001 Covilhã, Portugal
e-mail: castro.gomes@ubi.pt
S.M.R. Lopes
Department of Civil Engineering
University of Coimbra, Polo II, 3030 Coimbra, Portugal
e-mail: sergio@dec.uc.pt
Key words: aggregates, water absorption, permeability, concrete durability
Abstract
This paper presents an experimental study to evaluate the influence of physical properties of
aggregates on the durability of concrete. Different granite and limestone materials from various
locations in Portugal were characterized and used as aggregates to produce several concrete mixes,
with the same workability and volume proportions. The durability properties of these concrete mixes,
produced with different aggregates, were determined. Test procedures and results obtained are
discussed. The influence of aggregate types on concrete durability parameters is discussed.
1 Introduction
Concrete structures life time is usually shorted than expected. Rehabilitation of such structures is
usually expensive, which justifies continuing research on the domain of concrete durability. Although
F. Pacheco-Torgal, J.P. Castro-Gomes, S.M.R. Lopes
knowledge to improve concrete durability is already significant and there is a very large number of
research works produced, its reflection on practice is far to be significant. Compressive strength is, in
practice, still the main parameter to design concrete, adopted by major construction companies. Is in
fact the only parameter required to be tested. The existing recent regulations, ENV206 and others, are
quite incomplete in what respects designing durable concrete for a predictable life. Furthermore, there
is not a common test, or methodology, that can be consider unanimously by all as the most
representative to predict concrete durability, and as universal as the compressive strength test.
Apart from these issues, there is still the need to study more about concrete durability, in particularly,
regarding the roll of aggregates. Aggregates can be of different types and its quality surely influences
concrete quality. Aggregates occupy, in volume, the larger proportion of concrete constituents, which
really justifies a greater afford to research on this field.
This work presents partial results of a research project that has as main objective the study of
aggregates influence on concrete durability parameters. For this research, aggregates of different types
were obtained from four Portuguese districts, namely, Castelo Branco, Coimbra, Portalegre and Évora.
These aggregates were collected from granite and calcareous rocks and also presented different
textures. Physical and mechanical properties of these aggregates were quantify, such as, abrasion,
surface hardness, uniaxial compressive strength, ultrasonic pulse velocity, capillarity water absorption,
vacuum water absorption and oxygen permeability. The concrete permeability parameters, like
capillarity water absorption, vacuum water absorption, oxygen and water permeability, produced with
these aggregates, are in accordance to their physical and mechanical properties, as is presented.
2 Properties of rocks and aggregates used in this study
2.1 Rocks texture and macroscopic characteristics
The aggregates were obtained from centre region of Portugal. The range of aggregates study included
three types of granites, three types of calcareous and one gabbro. Fig.1 and fig.2 presents samples of
all different materials used in this study.
Figure 1: Samples of different granite and gabbro materials used in this study
(From left to right: G1,G2,G3,G4)
Granites were designated as G1, G2 and G3; calcareous designated as C1, and C3 and grabbro
designated as G4. The aggregates texture and macroscopic characteristics are described, as follows:
G1-Granite of Capinha; medium/fine granulated; G2-Granite of Alpalhão; fine granulated and of
homogeneous grey colour;; G3-Granite of Évora; medium/fine granulated; C1-Calcareous of
Cantanhede-Portunhos; light colour, white-yellowish, very fine granulated, compact and
homogeneous; C2-Calcareous of Condeixa-a-Velha; beige-brownish, very fine and compact
granulated; C3-calcareous of Vila-Viçosa; cristaline calcaroues, very fine granulated, compact and
XXX IAHS, September 9-12, 2002, Coimbra, Portugal
homogeneous; G4-Gabrodiorite (gabbro) of Crato-Alter Pedroso; granular texture and very fine grain,
with very dark grey coloration.
Figure 2: Samples of different calcareous materials used in this study
(From left to right: C1,C2,C3)
2.2 Experimental methodology and tests used for rocks and aggregates characterization
The main physical and mechanical properties of these rocks were quantified, by the following tests:
ultrasonic pulse velocity, surface hardness, uniaxial compressive strength, capillarity water absorption,
vacuum water absorption, and oxygen permeability. The first four tests were performed on cylindrical
specimens with 5 cm diameter and 10 cm high, while the last two tests were done on smaller
cylindrical samples of 5cm diameter and 4 cm high. All cylindrical specimens were extracted from
rock samples, as show in fig. 2.
Figure 2: Typical cylindrical rock specimens tested (left 5:10cm; right 5:4cm)
Sieve analysis, density, water absorption, Los Angeles abrasion, and slake abrasion were also
determinate for each aggregate type, but in this case, on regular crushed aggregates.
All tests were performed according to Portuguese standards or recommendations. Vacuum water
absorption and oxygen permeability was done according to a specific method, as detailed presented
elsewhere. [1, 2, 3]
2.3 Rocks and aggregates physical and mechanical properties
Tab. 1 presents the results obtained on cylindrical specimens extracted from rocks. Tab. 2 presents the
results obtained on aggregates that were produced from each rock type. All results presented in both
tables are medium values obtained from testing of 6 to 9 specimens.
F. Pacheco-Torgal, J.P. Castro-Gomes, S.M.R. Lopes
Table 1: Results obtained on cylindrical specimens extracted from rocks.
(medium values of 6 to 9 specimens)
Granites Gabbro Calcareous
Rock
Test G1 G
2 G
3 G
4 C
1 C
2 C
3
Ultrasonic pulse
velocity (m/s) 4500 3730 5140 6380 6020 6230 5790
Surface hardness
(rebound) 40 42 52 50 45 42 46
Compressive
strength (MPa) 121 152 102 172 62 44 56
Capillary water
absorption coef. 0.0516 0.0117 0.0077 0 0.0469 0.0165 0.0071
Vacuum water
absorption (%) 0.88 0.72 0.48 0 0.084 0.0018 0.29
Oxygen
Permeability (m2) 3.0x10-18 0
0 0 0 0 0
Table 2: Results obtained on aggregates produced from rocks
Granites Gabbro Calcareous
Rock
Test G1 G
2 G
3 G
4 C
1 C
2 C
3
Density
(kg/m3) 2610 2540 2580 2670 2610 2510 2580
Water (immerse)
absorption 24h(%) 1.5 2.4 1.4 1.8 3.2 2.8 1.7
Los Angeles
abrasion (%) 27 24 22 12 17 19 37
Slake
abrasion (%) 98.2 98.9 98.9 99.2 98.1 97.9 92.2
3 Characteristics of concrete produced
3.1 Concrete mixing and curing conditions
Concrete mixes were made with Portland cement II32.5, natural sand, water, and coarse aggregates of
each rock type. Two sizes of coarse aggregates were used; 9/15 and 15/25. The Faury method was
adopted to calculate a concrete mix with S2 workability and for a C20/25 strength classe. The w/c ratio
was maintained constant, with a value of 0.53. The ratio between fine and coarse aggregate was also
constant to a value of 0.82. Concrete were cured for 90 days, immerse in water saturated with lime.
3.2 Concrete testing methodology
Concrete compressive strength was determinate at 28 days. Capillary water absorption, vacuum water
absorption, oxygen and water permeability was determinate after 90 days curing to assume that the
cement hydration would be superior to 80%. These last three properties were determinate on
XXX IAHS, September 9-12, 2002, Coimbra, Portugal
cylindrical specimens of 5 cm diameter and 4 cm high extracted from cubes and identical, in shape, to
the rock specimens. [3]
3.3 Concrete Physical and mechanical properties
Tab. 3 presents the medium results of concrete physical and mechanical properties.
Table 3: Properties obtained on different concrete mixes produced with aggregates from different
rocks. (Medium values of 3 to 9 specimens)
Granite Concrete Gabbro
Concrete Calcareous concrete
Rock
Test
G1 G
2 G
3 G
4 C
1 C
2 C
3
Compressive
strength fck(MPa) 26.7 27.3 27.4 25.2 25.2 27.2 25.6
Capillary water
absorption coef. 2.59 1.9 1.4 1.63 0.85 1.96 1.56
Vacuum water
absorption (%) 15 16 15 15 16 17 18
Oxygen
Permeability (m2) 1.1x10-16 1.7x10-16 1.4x10-16 1.4x10-16 1.6x10-16 1.5x10-16 1.6x10-16
Water Permeability
(m2) 5.9x10-18 6.7x10-18 5.2x10-18 3.5x10-18 5.5x10-18 3.9x10-18 4.1x10-18
4 Analysis of results
4.1 Rocks and aggregates properties
When comparing the results of vacuum water absorption (P) with ultrasonic pulse velocity (U),
obtained for all cylindrical rock specimens, a relatively good linear correlation was found. Other
exponential correlation was also found, for all rocks, between P and capillary water absorption (C), as
presented below:
P = 2.1 – 0.0003 U (R2 = 0.837) (1)
P = 13 C1.1 (R2 = 0.933) (2)
The water absorption results obtained for aggregate specimens and vacuum water absorption results
obtained for rock cylindrical specimens are quite different. The results show that aggregates absorb
more water than the original rock. This is obviously a result of aggregates crushing phase that makes
its texture more roughness and with more micro fissures than on the original rock.
According to other authors, the results obtained on physical and mechanical tests indicated that all type
of rocks and aggregates, used in this study, are of good quality. This is evident, according to ultrasonic
pulse velocity results, as well as surface rebound and compressive strength. Such good quality is
particularly evident on oxygen permeability results. [4]
F. Pacheco-Torgal, J.P. Castro-Gomes, S.M.R. Lopes
4.2 Concrete durability properties
The results obtained for concrete durability properties are between relative small ranges, respectively
for each property. However, concrete made with C1 aggregate has lower water capillary absorption
while concrete made with G1 aggregate has the highest value, when compared to the other results that
are between the same range values.
The results obtained for vacuum water absorption, oxygen and water permeability, of all concrete
mixes, are in the same order of magnitude. There is not a clear difference between those values.
This indicates that the quality of concrete mixes produced with the different aggregates is
approximately the same, in all cases.
A linear relationship was found between concrete values absorption (Pc) and oxygen permeability (Kc).
However, in this study the range of Pc varies little, only from 15 to 18%, thus, this linear relationship is
not adequate to represent those properties. The exponential relationship is the adequate equation to
correlate those properties, as found by others [2, 5, 6].
Values obtained for Pc and Kc are relatively high in what respects durability. However the concrete
mixes produced are the most used in current construction.
4.3 Aggregates influence on concrete durability properties
Since the durability parameters obtained, for this study, varied between small ranges, as well as the
aggregates properties, it was not possible to correlate it. This indicates that good quality aggregates,
independently of its texture, do not influence durability properties of concrete used for current
construction, like the case of C20/25 with S2 workability.
The values of Pc and Kc were also determinate for the mortar concrete phase only. The mortar phase
was produced in identical mixing conditions of concrete mixes, and parameters Pc and Kc obtained,
were of 22% and of 1.7x10-16 m2, respectively.
Concrete and mortar permeability corrected results were compared, i.e. each Kc values were divided
first by Pc2, and afterwards compared. The corrected concrete permeability results are show in tab. 4.
The corrected permeability for mortar is of 34x10-16 m2.
Table 4: Corrected oxygen permeability values
Granite Concrete Gabbro
Concrete Calcareous concrete
Rock
Test
G1 G
2 G
3 G
4 C
1 C
2 C
3
Vacuum water
absorption (%) 15 16 15 15 16 17 18
Oxygen
Permeability (m2) 1.1x10-16 1.7x10-16 1.4x10-16 1.4x10-16 1.6x10-16 1.5x10-16 1.6x10-16
Corrected oxygen
permeability (m2) 49x10-16 64x10-16 57x10-16 60x10-16 50x10-16 59x10-16 54x10-16
The results presented on tab. 4 show that all concrete mixes have higher corrected permeability results
than the corresponding results for mortar phase. This is in accordance to other authors, which have
found an effect of coarse aggregate size on concrete durability parameters. [7]
The aggregate size effect is apparently of more importance to concrete durability than the use of
aggregates of different type and with different texture.
XXX IAHS, September 9-12, 2002, Coimbra, Portugal
5 Conclusions
This experimental study shows apparently that there is not much difference on concrete durability
parameters when produced either with granite, gabbro or calcareous coarse aggregate. Obviously, this
study is valid for C20/25 quality concretes and for good quality aggregates.
The results obtained for vacuum water absorption, oxygen and water permeability, of all concrete
mixes, are in the same order of magnitude. There is not a clear difference between those values.
This indicates that the quality of concrete mixes produced with the different aggregates is
approximately the same, in all cases.
However, the coarse aggregates phases apparently contribute more to concrete permeability than
mortar phase; this has obviously relation to the aggregates-cement interface phase and should be more
investigated in future.
Acknowledgements
The authors are grateful for the financing grant given by the Foundation for the Science and
Technology (FCT), program POCTI, project 36027/99 “influence of physical properties and
morphological parameters of granites and calcareous aggregates on the permeability of concrete”.
References
[1] Castro-Gomes, J.P., Pereira de Oliveira, L.A., Gonilho Pereira, C.N. and Pacheco Torgal, F.,
Absorption and Permeability tests of Aggregates «only available in Portuguese», in 10th
Portuguese National Congress on Geotecnics, April, 2002, Lisbon, Portugal.
[2] Castro-Gomes, J.P., Pereira de Oliveira, L.A., Gonilho Pereira, C.N. and Pacheco Torgal, F.,
Discussion of Aggregate and Concrete Water Absorption and Permeability Testing Methodology,
in XXX IAHS, September 9-12, 2002, Coimbra, Portugal.
[3] Pacheco-Torgal, F., Influence of Physical Properties of Ganite and Calcareous Agregate on
Concrete Durability, «only available in Portuguese», Msc Thesis (submitted for discussion), May
2002, Department of Civil Engineering, University of Coimbra, Portugal.
[4] Saraiva, A.L. Almeida, Propriedades geotécnicas dos granitos em função do seu grau de
alteração: caso dos granitos de Santa Comba Dão, «only available in Portuguese», Museu e
Laboratório Mineralógico e Geológico, nº93, Universidade de Coimbra, Coimbra, 1982, pp 58-
70.
[5] B.A. Gaffar, The Effect of Environmental Curing Condition on the Gas and Water Permeability
of Concrete, unpublished PhD Thesis, Civil Engineering Department, the University of Leeds,
UK, 1995.
[6] J.G. Cabrera, A.R. Cusens and C.J. Lynsdale, Porosity and Permeability as Indicators of
Concrete Performance, Durability of Structures, International Association for Bridge and
Structural Engineering, IABSE Symposium, Lisbon, Sept. 1989.
[7] Mehta, P.K., Concrete in marine environment, Elsevier Science Publishers, 1991.
