Civil Engineering Reference
In-Depth Information
MK (see Fig. 9.4). This increase at 90 days is about 6% for a 45% GGBFs
and 15% MK replacement combination (Güneyisi et al., 2011).
Figure 9.5 indicates the effect of MK, FA and GGBFs replacement
combinations (quaternary blends) on the compressive strength values. The
quaternary blends provide significant increases compared to the binary use of
FA replacements. While 60% FA replacement results in compressive strengths
of 48 and 65 MPa at 28 days and 90 days, respectively, the quaternary use
of 22.5% FA, 22.5% GGBFs and 15% MK replacements provides 60% and
35% compressive strength increases at 28 days and 90 days (see Fig. 9.5)
(Güneyisi et al., 2011).
The compressive strength of sCC with MK increases much faster than sCC
containing GGBFs during the initial setting time (up to 2 days). This could
be related to higher reactivity caused by the binder blended with MK. After
this period, the increase in relative strength is similar for both sCC mixes,
but sCC with MK always provides higher strength values (Vejmelková et
al., 2011).
Most sCC with FA combinations demonstrate higher splitting tensile
strength values compared with the normal vibrated concretes, due to the
high paste content, which exhibits slightly higher deformability. The splitting
tensile strength values obtained from sCC with FA combinations are about
10% of the corresponding compressive strength (Dinakar et al., 2007). The
splitting tensile strength of sCC increases with the decrease in percentage
of FA content and the water-to-cementitious materials ratio (Pathak and
siddique, 2012).
The high-volume FA content in sCC reduces the static elastic modulus
since it leads to higher paste volume and lower coarse aggregate content.
The static elastic modulus of sCC is about 8% lower than that of normal
concrete with similar compressive strength (Dinakar et al., 2007).
9.5 Durability of self-compacting concrete (SCC)
with high-volume supplementary cementitious
materials (SCMs)
The chloride diffusivity of sCC with high-volume FA replacements is much
lower than in the corresponding normal vibrated concretes. Although sCC
with high-volume FA demonstrates higher absorption and permeable voids,
it shows better performance in terms of chloride permeability. This could be
due to the chloride ion penetration, which depends on the chloride binding
capacity of the constituent materials (Dinakar et al., 2008). sCC with high
volume FA shows significantly lower chloride ion permeability than sCC
without FA and normal concrete mixes (Amrutha et al., 2011; Pathak and
siddique, 2012).
