Civil Engineering Reference
In-Depth Information
recycled concrete coarse aggregate (rCCA), recycled brick coarse aggregate
(RBCA), recycled mortar coarse aggregate (RMCA), recycled concrete fine
aggregate (RCFA), recycled brick fine aggregate (RBFA) and recycled mortar
fine aggregate (RMFA) (Cabral, 2007).
Generally, recycled aggregates have a bulk density and a specific gravity
lower than those of natural aggregates. For the specific gravity, this reduction
is a function of the characteristics for the raw materials of the same type,
since they are less dense than the natural coarse aggregate. regarding the
bulk density, the reduced density of the material itself and the characteristic
of high porosity aggregates, the irregular shape of the aggregates in particles
contributes to the reduction of the same. However, these stated reductions
are also dependent on the particle size of recycled aggregates and on the
composition of recycled aggregate. Agrela et al. (2011) noticed an increment
of 2.5% and 8.3% in a specific gravity of recycled concrete aggregate when
compared with mix recycled aggregate and ceramic recycled aggregate
specific gravities, respectively.
In general, some of the other characteristics of recycled aggregates, such
as resistance to impact, to abrasion, to crushing and mass loss, among others,
are also considerably lower than those of natural aggregates (ravindrarajah
and Tam, 1985, 1987b; Hansen, 1992; Zakaria and Cabrera, 1996; Nagataki
et al., 2000; Senthamarai and Manoharan, 2005).
14.4 Characteristics of concrete with recycled
aggregates
Since the performance of concrete with the replacement of natural aggregates
by recycled aggregates is modified, it is necessary to understand the behavior
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10
0
RCCA
RMCA
RCBA
RCFA
RMFA
RFBA
0
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Time (min)
14.4
Water absorption of recycled aggregates by time (Cabral, 2007).
