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Recycling of waste glass in construction materials 163
Figure 6.8 Use of Eco-sand product for laying course material in block pavements (Glass
Tech Recycling Ltd.).
as natural sand and meet the grading requirement of the standard (BS 7533-
3:2005).
A novel polymer concrete (PC) was synthesised by the authors by mixing epoxy
resins and waste glass as aggregates (Kou and Poon, 2013). This glass-based PC
had acceptable physical properties, good mechanical integrity and enhanced chemi-
cal resistance that make it attractive for a number of applications, especially for
decorative industrial applications.
Recently, Lu and Poon (2018) prepared an alkali activated cement (AAC) mortar
using waste soda-lime-silica glass. The waste glass was used simultaneously as
a precursor and fine aggregates in the AAC mortar. Similarly to the case of OPC-
based mortar or concrete, the increased replacement of natural sand by GC
gradually improved the workability of the AAC mortar due to the smooth surface,
non-absorption and larger particle sizes of the glass. Also, the compressive strength
of AAC mortar slowly decreased as the GC content increased. An encouraging result
was that the use of waste glass in AAC mortar did not cause severe deterioration in
strength after being subjected to a high temperature (800 C). On the contrary, the
introduction of GC could mitigate the strength loss after exposure to high tempera-
tures. The reason may be that the replacement of river sand by GC alleviated the ther-
mal expansion mismatch between the AAC paste and the expanding aggregates.
6.7 Conclusion
Hong Kong generates about 100,000 t of waste glass every year. As glass is chemi-
cally inert and has high intrinsic strength, it is feasible to turn to waste glass as a
valuable resource for construction materials rather than disposing it with general
refuse ending up in landfills. Since 2015, the Hong Kong Environmental Protection
Department has started to expedite the work on expanding the glass bottle recycling
