Civil Engineering Reference
In-Depth Information
Table 4.14 Carbonation depth of cement mortar specimens (Akcaozoglu et al.
2010
)
Amount in mortar (%)
Depth of carbonation (mm) in
Cement
Slag
PET-
aggregate
Normal aggregate
Water
7 days
28 days
90 days
180 days
51.28
0
25.64
0
23.08
0.3
1.2
4.3
5.0
25.64
25.64
25.64
0
23.08
0.3
1.7
5.5
7.6
33.90
0
16.95
33.90
15.25
0.0
1.4
4.8
5.9
16.95
16.95
16.95
33.90
15.25
0.6
2.5
6.8
8.5
for the mortar with PET aggregates only. According to the authors, PET and sand
aggregates used together did not combine sufficiently and the resulting mortar
became porous. On the other hand, the depth of carbonation for concrete with slag
is significantly higher than for the mortar prepared by using cement as the only
binder.
4.6.3.3 Shrinkage
Frigione (
2010
) found an increase in drying shrinkage due to the incorporation of
5 % PET-aggregates in concrete at different experimental conditions due to the
lower modulus of elasticity of concrete with plastic aggregates than that of con-
ventional concrete. However, the shrinkage of concrete with PET-aggregates was
acceptable for various uses as structural concrete.
From their experiments on the use of PVC waste granules as a partial volu-
metric replacement of natural sand in concrete, Kou et al. (
2009
) found decreasing
drying shrinkage with increasing content of plastic aggregates (Fig.
4.42
).
According to the authors, PVC granules are impermeable and do not absorb water
when compared to sand and do not shrink either, and hence are able to reduce the
overall shrinkage of concrete.
Fig. 4.42 Drying shrinkage
of concrete with fine PVC
aggregates (Kou et al.
2009
)
