Civil Engineering Reference
In-Depth Information
2.0
Control
Green
Amber
Flint
Blue
1.8
26-week test period
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
Limit for non-expansive
0.0
0
5
10
15
20
25
30
35
40
45
50
55
Time (weeks)
11.15
Effects of glass colour on ASR expansion (ASTM C 227
condition) (Zhu et al., 2009).
Idir et al.
(2010) found that the magnitude of expansion increases in the
sequence flint-amber-green, and the expansion behaviour of prisms containing
flint glass was similar to that of the control. Jin et al. (2000) also observed
concrete with flint glass aggregate producing the largest dimensional change.
One possibility is that differences in the ASR behaviour of the different
coloured glass samples reflect variations in manufacturing processes used
for different glass products, which would influence levels of internal stress
and consequently rates of leaching dissolution of the glass.
Last but not at least, the size of glass aggregate exerts evident influences on
the expansion rate and value, with finer glass particles displaying considerably
lower expansion.
As shown in Fig. 11.16, the ASR expansion increased with
the increase of glass aggregate size (Zhu et al., 2009). When the size of glass
particle is smaller than one particular level, the glass particles themselves
will not generate deleterious expansion (Meyer and Baxter, 1997; Shi et al.,
2004). however, glass powder has a very high content of alkalis, and the
alkalis in glass powders can be leached out, resulting in alkali-aggregate
reaction (AAR) expansion when the aggregate is alkali-reactive. This particular
size varies in a large range according to different observations, because it is
also related to composition, colour and thermal history of glass. Therefore,
it is necessary to find the maximum size that does not generate deleterious
expansion by experiments for different sources of waste glass. There are also
