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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
Concrete properties produced with recycled coarse aggregates
with recycled aggregates, type G1, showed lower resistances than
the reference concrete, which shows their limitation, whereas con-
crete with G2 showed superior strength to the reference concrete.
The G2 aggregate showed smaller particles than the natural aggre-
gates, which collaborates enough to provide a stronger transition
zone, but besides the difference between the superficial texture and
larger porosity of G2 in relation to the natural aggregates, allowed a
larger adherence to the paste, which helped the concrete with G2 to
overcome the strength of the reference concrete. Table 4 shows the
aspect of the rupture of the samples of the RAC.
The concretes with recycled fine aggregates showed smaller resis-
tances in relation to the concrete with natural sand. In general, the
compressive strength obtained by the concrete agrees with NBR
6118 [20] in structural concretes.
The related aspects with the rupture and detachment of the coarse
aggregate are shown in table 4. They also confirm that which was
mentioned in terms of the resistance of the concrete when the w/c
ratio is altered. For the w/c = 0.67, the rupture happened predomi-
nantly in the non-rocky aggregates (ceramic and mortars) which have
low resistance and, probably, similar strength to the paste. The rocky
aggregates, just as if detached, prove the weakness of the transition
zone. For the w/c = 0.4, there was also some rupture in the rocky
aggregates, which showed that in these cases the paste was more
resistant. The concrete of w/c = 0.5 showed an intermediate behavior.
Figure � � �ater absorption and air content of the concretes
Figure � � �ir-permeability time of the concretes