Civil Engineering Reference
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Fig. 5.64 Water absorption
capacity of concrete versus
coarse RCA content (Kwan
et al.
2012
)
Fig. 5.65 Water absorption
due to immersion of
conventional concrete and
RCAC's (Sagoe-Crentsil
et al.
2001
)
Sagoe-Crentsil et al. (
2001
) observed water absorption about 25 % higher due
to the complete replacement of coarse basalt aggregate by RCA (Fig.
5.65
). The
concrete specimens used in this research were moist cured for 6 days after de-
moulding and then cured at 23 C at 50 % room humidity before determining the
water absorption capacity. Adding slag cement or increasing 5 % OPC content did
not have any beneficial effect on the water absorption capacity of RCAC. Grdic
(
2010
) observed water absorption capacity about 0.15-0.37 % higher in self-
compacting concrete (SCC) due to a 50-100 % replacement of coarse NA by
RCA. They did not observe any water penetration for 50 and 100 % coarse RCA
based SCC; on the other hand, the control SCC (with NA only) had a penetration
of 10 mm.
Soutsos et al. (
2011
) observed increasing water absorption capacity of concrete
paving blocks as the replacement ratio of coarse and fine NA by similar sized RCA
and recycled masonry aggregates (RMA) increased. This increase was higher for
concrete with fine recycled aggregate than with coarse one. These results are
presented in Fig.
5.66
. The authors observed that the replacement of 55 or 25 % of
coarse or fine NA by coarse and fine RCA respectively in concrete paving blocks
allows maintaining the water absorption capacity below the BS EN1338 specified
maximum limit of 6 % along with reasonably good CS and STS. For recycled
masonry aggregates, these threshold replacement ratios were respectively 50 and
