Civil Engineering Reference
In-Depth Information
it is known that
C
3
A binds chloride. Even though opC is supposed to bind
more chloride ions and to decrease chloride penetration due to having C
3
A
more than slag cement, the studies prove the contrary. In the analysis done
by cement with GGBFS, it is observed that the penetration of chloride ions
in opC is reduced, because the gels of C-S-H bind more chloride. owing
to the fact that the C-S-H occurring after the hydration of slag cement is
more than opC, due to binding chloride ions, the chloride permeability of
slag concrete mainly decreases. Sato et al. (1998) examined the effects of
different cure conditions (natural environment cure and wet cure) on chloride
permeability of concrete with 70% GGBFS. At the end of their study, they
observed that the use of GGBFS at a rate of 70% decreases the chloride
ion permeability.
Güneyisi and Gesoğlu (2008) mentioned that the chloride permeability
decreases considerably in concretes that include more than 50% of GGBFS,
as shown in Fig. 10.5. For example, permeability value of 70 and 80% of
GGBFS concretes at the age of 90 day is 1000 coulombs and this value is
qualified as wonderful in accordance with ASTM 1202.
Corrosion resistance
Song et al. (2003) observed the free chloride permeability of the concrete
with GGBFS and found that the higher the amount of GGBFS, the lower
the values of free chloride permeability. Additionally, they found that the
free chloride permeability of the concrete with 70% GGBFS is 43.8% less
than of the control concrete. Yeau and Kim (2005) examined the corrosion
6000
Dry cured 28 days
Dry cured 90 days
Wet cured 28 days
Wet cured 90 days
5000
4000
3000
2000
1000
0
0
10
20
30
40
50
60
70
80
90
100
Replacement levels of slag, %
10.5
Effects of slag replacement and curing conditions on 28- and 90-
day chloride permeability of concretes (Güneyisi and Geso
ğ
lu, 2008).
