Civil Engineering Reference
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self-compacting concretes with good compressive strength at an early age which
could be poured without vibration, in line with precast prestressed beam production
demands.
The materials used were: cement CEM I 52.5R and calcareous crushed aggre-
gates based on
bers
(RC65/40BN) were low carbon with hooked-ends (40 mm long, 0.62 mm diameter
and a nominal aspect ratio (length/diameter) equal to 65) and a tensile strength of
1,225 MPa.
The water/cement ratio and superplasticizer dosage were determined to reach the
required strength and slump
ller, sand and 7/12 mm size coarse aggregates. The steel
ow, respectively.
SCC mix design criteria [
1
], most of which are based on laboratory tests, suggest
an increase in
fl
nes content. The
nal application needs experimental veri
cation
under working conditions, as when SCC contains
bers the
nes content must be
higher.
Based on the authors
previous research work [
2
], the concrete mix design was
determined by adapting solid grading (including cement) to the theoretical Bolomey
particle size distribution curve [
3
], de
'
ned as:
p
¼
a
þ
ð
100
a
Þ
ð
d
=
D
Þ
1
=
2
ð
4
:
1
Þ
where
“
p
”
is the percentage passed through a
“
d
”
sieve,
“
D
”
is the concrete
'
s
maximum aggregate size and
is the Bolomey parameter [
3
], which depends on
the desired workability of the concrete and aggregates properties.
For the concretes in this study, the
“
a
”
“
”
a
values used were: a = 16 for SCC and
“
”
a = 20 for SCFRC. The relatively low
a
parameter was due to the inclusion of
well graded sand.
Table
4.1
shows the mix design for both concretes. The theoretical and actual
particle size distribution curves are plotted in Fig.
4.1
.
Table 4.1 Mix design
adaptation (kg/m
3
)
(kg/m
3
)
SCC
SCFRC
7/12 aggregate
846
721
Sand
924
985
Filler
41
50
Cement
440
460
Water
198
205
Fibers (RC65/40BN)
0
60
Superplasticizer
11.1
12.8
W/C ratio
0.45
0.45
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