Geoscience Reference
In-Depth Information
Figure 8.7
Schematic diagram of CO
2
injecting system (
after
Kazemian
et al.
, 2011a).
Figure 8.8
Undrained shear strength ratio versus time of peat treated with cement and cement-slag
mixtures and cured in water containing dissolved CO
2
(
after
Kazemian
et al.
, 2011a).
that available in natural peat) was accomplished by varying the ratio of components
in the generator (yeast, sugar and water).
The depth of carbonation was determined using a solution of 1% phenolphthalein
in 70% ethyl alcohol as an indicator. If free calcium hydroxide (Ca(OH)
2
) is present, it
is coloured red or pink, whereas it remains uncoloured along the depth of carbonation.
The effect of CO
2
on cementation and pozzolanic reactions is shown in Figure 8.8.
This shows the shear strength ratio of samples (cured in water containing dissolved
CO
2
[Su
(
CO
2)
] to cured in distilled water [Su
(Dist
.
)
]) versus time, for fibrous, hemic and
sapric peats treated with cement or the cement-slag mixture.
A ratio of one indicates that there is no effect on the cementing process; greater
than one indicates an improvement and less than one indicates a negative effect. The
UCS results indicate that the shear strength of the samples cured in CO
2
dissolved
water was less than that for the samples cured in distilled water.
