Page 190 - New Trends in Eco efficient and Recycled Concrete

162 New Trends in Eco-efficient and Recycled Concrete

blocks. Nevertheless, a single outlet cannot meet the increasing supply of waste
glass in particular when the PRS scheme is implemented. Therefore, more research
is needed to explore other potential applications of recovered glass materials with
the view to diversifying recycling outlets.
Spiesz et al. (2016) developed a translucent and air-purifying concrete containing
waste glass aggregates (see Fig. 6.7). They used two different types of TiO 2 in con-
crete to analyse the effect of glass aggregates on the photocatalytic degradation of
air pollutants. The obtained results indicate that the developed glass concrete has
satisfactory mechanical properties, durability, translucency and enhanced air purifi-
cation properties. Chen and Poon (2009) also combined the use of GC as aggregates
and nano titanium dioxide as photocatalytic materials in preparing the surface layer
of the paving blocks. The results showed a significant enhancement of the photoca-
talytic activity due to the use of GC as aggregates in the surface layers. In addition,
Gou et al. (2012) investigated the photocatalytic activities of self-compacting glass
mortars. They found that mortars prepared with transparent GC showed a slightly
higher NO removal rate than those prepared with light green GC.
Oliveira et al. (2013) found that the use of very fine glass aggregates was viable
in the production of renderings and most properties were improved with the incor-
poration of up to 20% fine glass aggregates.
Due to the relatively lower requirement for the sub-base layer of road pavement,
GC was considered as a sustainable material in pavement sub-bases and laying
courses. Arulrajah and Ali et al. (Arulrajah et al., 2013, 2014; Ali et al., 2011; Ali
and Arulrajah, 2012) investigated the geotechnical performance of sub-base layer
materials containing various percentages of WGA. The field results indicate that
the WGA blend was a potential alternative material for use in footpath sub-bases
with satisfactory engineering performance. Furthermore, Imteaz et al. (2012) con-
cluded that WGA could be safely used in pavement sub-bases without posing the
undue risk of environmental contamination.
In the United Kingdom, the Glass Tech Recycling Ltd. company has produced a
clean glass sand after washing the crushed WGA for use as a paving sand (see
Fig. 6.8). According to the company, this Eco-sand product could perform as well

Figure 6.7 Translucent concrete plates containing waste glass (Spiesz et al., 2016).