Page 185 - New Trends in Eco efficient and Recycled Concrete

Recycling of waste glass in construction materials 157

(A) 100 Compressive strength Flexural strength 14 (B) 0.8
90 0.7 CON
12 GP20
80 10 0.6 FA20
Compressive strength (MPa) 60 8 6 Flexural strength (MPa) Rate of expansion (%) 0.5
BS20
70
MK5
0.4
50
0.3
40
30
20 4 0.2 Threshold
0.1
2
10 0.0
0 0 0 7 14 21 28
CON GP20 GP50 FA20 FA50 BS20 BS50 MK5 MK15
Age (days)
Figure 6.3 Mechanical properties and ASR of glass mortars with different SCMs (Lu et al.,
2017a). (A) Strength at 90 days of curing; (B) ASR expansion of mortars.
Note: CON, GP, FA, BS and MK mean control sample, sample prepared with glass powder
(GP), fly ash (FA), ground granulated blast-furnace slag (GGBS), metakaolin (MK). The
numbers in the mix designation correspond to the percentage of SCMs present in the binder.
ASR, Alkali silica-reaction.
improve the resistance of the glass mortars to sulphuric acid attack and this positive
effect was more pronounced when finer GP was incorporated. When the glass mor-
tars were subjected to a high temperature (800 C), the inclusion of GP into the mor-

tars was more able to mitigate the flexural and compressive strength losses
compared to the control glass mortar prepared without the use of GP. Therefore,
there is potential to produce high-performance architectural mortars with excellent
mechanical and durability properties by utilising recycled glass to fully replace nat-
ural aggregates and partially replace cement.

6.4 Application of waste glass in paving blocks

There have been studies aimed at investigating the feasibility of using waste GC to
replace natural fine aggregates for the production of concrete paving blocks.
According to the work of Ling and Poon (2014b), GC was used to replace natural
aggregates for the purpose of reducing the drying shrinkage and water absorption
due to the impermeable properties of the glass. In addition, they found that the use
of GC in concrete paving blocks improved the photocatalytic performance for
removing air pollutants when used together with nano TiO 2 . To make use of the
recycled materials to produce eco-friendly (100% recycled materials as aggregates)
concrete blocks with good quality, Poon and Lam (Poon and Lam, 2008) recom-
mended preparing blocks with 50% GC and 50% recycled crushed aggregates and
stated that the abrasion resistance and skid resistance of the blocks were increased
as the aggregates to cement ratio increased. Turgut and Yahlizade (2009) reported
that the blocks prepared with 20% fine GC as fine aggregate replacement performed
better in flexural strength, splitting tensile strength and abrasion resistance com-
pared to the control sample. However, Lee et al. (2013) showed that inclusion of