Civil Engineering Reference
In-Depth Information
Table 4.6 Compressive strength behaviour of concrete after accelerated ageing
Concrete type
Compressive strength (MPa)
Before ageing
After 32 days curing at 70 C
After curing at 70 C for
32 days plus moist curing
for 90 day
Pellegrino and Gaddo (
2009
)
Control
30.4
33.1
32.9
EAF-slag
44.4
41.9
43.4
Manso et al. (
2006
)
Control
38.5
39.6
EAF-slag-1
33.7
35.9
EAF-slag-2
35.3
39.4
EAF-slag-3
30.2
33.5
EAF-slag-4
30.7
34.1
Table 4.7 Compressive strength before and after autoclave ageing followed by weathering
(Manso et al.
2006
)
Concrete type
Compressive strength (MPa)
Before ageing
After ageing
Appearance
Control
38.5
18.4
Superficial cracking
EAF-slag-1
33.7
20.9
Slight superficial cracking
EAF-slag-2
35.3
23.8
Slight superficial cracking
aggregates exhibited poorer compressive strength than concrete with EAF-slag
aggregates due to the difference in shape of these two aggregates. Their results are
presented in Table
4.7
.
Manso et al. (
2004
) evaluated the soundness of cement mortar with EAF-slag as
partial substitution of fine aggregates in concrete according to ASTM C1012, in
which cement mortar were subjected to ten cycles of repeated immersion in a
saturated Na
2
SO
4
solution followed by drying in an oven. They observed larger
deterioration in mortar with EAF-slag than in conventional mortar.
4.3.3.3 Freeze-Thaw Resistance
Manso et al. (
2006
) reported that concrete with steel slag aggregates exhibited
poorer performance than conventional concrete after 25 cycles of freezing and
thawing. Their results are presented in Table
4.8
. Out of four concrete mixes with
steel slag aggregates, the authors observed better performance for concrete with
EAF-slag-2, which exhibited slightly higher compressive strength as well as lower
porosity. The addition of an air-entraining admixture improved the freeze-thaw
resistance of concrete with steel slag aggregates. Pellegrino and Gaddo (
2009
)
observed about 7 % reduction in compressive strength for concrete with EAF-slag,
