Civil Engineering Reference
In-Depth Information
7.2.5 The RILEM Specification
The RILEM TC 121-DRG recommendation (1994) is a specification that deals
with recycled coarse aggregates with minimum size of 4 mm for concrete. As the
properties of fine RA fraction are vastly different from those of natural sand, there
is no specification for the fine fraction in the RILEM specification. It classes the
recycled coarse aggregates and indicates the scope of application for concrete
containing these RA classes in terms of acceptable environmental exposure classes
and concrete strength classes. Recycled coarse aggregates are classed as follows:
• Type I—aggregates which are implicitly understood to originate primarily from
masonry rubble;
• Type II—aggregates which are implicitly understood to originate primarily from
concrete rubble;
• Type III—aggregates which are implicitly understood to consist of a blend of
RA and NA; the composition shall have at least 80 % NA and up to 10 % type I
aggregate.
7.2.5.1 Recommendations for RA
The RILEM specification prohibits the use of RA with more than 15 % of harmful
materials which can retard the concrete hardening process. Table
7.13
shows some
other requirements for different types of RA. Unlike most of the other specifica-
tions, this one imposes several parameters.
The specified minimum density of type III aggregates that also contains a
minimum of 80 % NA is 2,400 kg/m
3
. If it is presumed that the density of NA is
Table 7.13
Requirements of coarse RA for concrete production (RILEM 1994)
Properties
Type I
Type II
Type III
Density at saturated surface dry (SSD) condition (kg/m
3
)
C1,500
C2,000
C2,400
Water absorption (%)
B20
B10
B3
Amount of material with SSD density \2,200 kg/m
3
(%)
-
B10
B10
Amount of material with SSD density \1,800 kg/m
3
(%)
B10
B1
B1
Amount of material with SSD density \1,000 kg/m
3
(%)
B1
B0.5
B0.5
Contaminants (bitumen, glass, metals) (%)
B5
B1
B1
Metals (%)
B1
B1
B1
Organic materials (%)
B1
B0.5
B0.5
Filler, \63 lm (%)
B3
B2
B2
Sand (%)
B5
B5
B5
Water soluble sulphite (%)
B1
B1
B1
Natural aggregates (%)
-
-
C80
Type I aggregate (%)
-
-
B10
