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73
IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 1
V. CECCONELLO | B. TUTIKIAN
from day 14, with the concrete cured at lower temperatures and
showing better results than those cured at higher temperatures.
At 28 days the ratio of resistance with the previous age followed the
trend of higher growth for lower temperatures. The variation of resis-
tance at this age was 21.7 MPa for a temperature of 15 °C, 38.6 MPa
for a temperature of 0 ºC, considering a 43% reduction in the range
of 15 °C, for the total range of 25 °C the reduction was 30%, similar
to the results in the referenced bibliography. For the age of 91 days
the ratio between the resistance of the concretes maintained the ten-
dency, with the cured at zero and 5 °C with higher rates of resistance
to compression. It is presented in Table 7 with all values grouped.
Figure 3 shows the behavior in graph form, where it was observed
the highest resistance to compression for concretes cured under
high temperatures at early ages, with the inversion occurring at 14
days, showing that the slow hydration is an advantage over time
for the concrete structure.
Such behavior is evidenced in Figure 4, which correlates the
compressive strength in MPa, in the ‘y’ axis, with the curing
temperature, in °C, in the axis ‘x’ to the ages of the tests of
the samples. It is observed the behavior of the outcomes at 1
Figure 2 – Evolution of resistance to
compression in air-conditioned room (20º C)
Table 7 – Evolution of compressive strength at 91 days
Resistência à compressão
°C
1 day
7 days
14 days
28 days
91 days
MPa
MPa
MPa
MPa
MPa
25
11,4
21,5
24,3
26,9
29,2
20
11
23,4
27,5
31
31,4
15
8,3
24,4
28,7
21,7
27,8
10
6,5
21,7
27,3
31,8
28,7
5
3,5
18
20,9
35,6
37,6
0
1,2
18,8
30,3
38,6
38,8
Figure 3 – Evolution of compressive strength
Figure 4 – Evolution of compressive
strength as a function of curing temperature
Evolution of compressive strength as a function of
curing temperature
0
10
20
30
40
50
0
5
10
15
20
25
30
t (°C)
fc (MPa)
1d
7d
14d
28d
91d
Linear (1d)
Linear (7d)
Linear (14d)
Linear (28d)
Linear (91d)