Civil Engineering Reference
In-Depth Information
1.0
14 days
56 days
147 days
35 days
91 days
189 days
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Control
<0.15
0.15-0.30 0.30-0.60 0.60-1.18
1.18-3
3.6
6.12
Particle size (mm)
11.16
Effect of glass size on ASR reactivity (flint, ASTM C1260
Condition) (Zhu et al., 2009).
suggested a pessimium sizes (particle size that causes maximum expansion)
(Jin et al., 2000), the pessimium size is related to composition, colour and
thermal history of glass as well.
Different approaches have been made to reduce or eliminate the expansion
of concrete containing glass aggregates. Practically, feasible concrete
mixtures with expansion values lower than the limit that will not result in
deleterious expansion, which may vary according to different test methods,
can be produced in the laboratory or the field application. These approaches
include: (1) reducing the size of glass particle, (2) restricting the glass content,
(3)introducing air entrainment, (4) using porous lightweight aggregate or
(5) supplementary cementing materials. Some admixtures such as lithium
compounds were used as ASR suppressors as well. Even the fine ground
glass powder itself can be used as ASR suppressors.
The introduction of air entrainment or use of porous lightweight aggregate
is an effective method to reduce or eliminate the expansion. It is well
known that porous aggregate can mitigate expansion resulted from AARs
(Collins and Bareham, 1987). In that case, pores in porous aggregate permit
the expansive reaction products to permeate into or relieve the expansive
pressure, then reduce or eliminate the expansion. For example, when the
volume of expanded shale is more than 60% of the total aggregate volume, the
expansion of the specimens is greatly reduced and far below the deleterious
