Thesis (MSc) - Cyprus International University. Institute of Graduate Studies and Research Environmental Sciences Department

Includes bibliography (sheets 52- 58)

ABSTRACT
Geopolymerization has become a modern method of transforming materials into suitable
products for different purposes. Generation and disposal of waste materials into
environment has become a prevailing situation resulting in vast environmental pollution.
The overall purpose of this study is to produce environmentally friendly construction
materials from waste through geopolymerization technique. In this work, bricks were
produced using coal ash (CA) and waste plastics (WP) in coarse and fine particle form.
For optimization experiments, several parameters and mixing ratios for coal ash to
activation ratios of 3:1, 3.5:1, and 4:1 were investigated. Activation liquid (NaOH:
Na2SiO3) ratio of 1:2 was used for all the experimental tests. The plastics were added
using two different measurement methods: mass/mass and volume/volume. The fine
plastic particles were added to the coal ash directly in the mechanical mixer at different
percentages (0, 5, 10, 12.2 and 15%). The manufactured bricks were analysed for density
and compressive strength after a curing period of 7, 14 and 28 days. Water absorption test
was also conducted on the manufactured bricks after 28 days of curing. Microstructural
analysis was carried out on the manufactured bricks specimens. According to findings
obtained on the 28th day after curing at room temperature indicates that bricks specimens
produced with coal ash to activation ratio of 3.5:1 and 15% fine plastic had a density value
of 1.53g/cm3
and a compressive strength value of 12.53 MPA. Bricks specimen produced
with coal ash to activator ratio of 4:1 and 5% fine plastic produced compressive strength
of 13.8 MPA with a density value of 1.65g/cm3
. The test result for both 3.5:1 and 4:1 brick
sample show density and compressive strength values that complies with ASTM C62 and
TS EN 771-1 acceptable standards and can be used for construction purpose. For both
3.5:1 and 4:1 brick specimen made with fine plastic, lower water absorption (%) values
were obtained. Microstructural analysis: XRF, XRD, FTIR and SEM were also carried
out and the results were discussed in detail. In general, use of fine plastic improves the
characteristics of the brick and therefore should be considered as an alternative in the
production of geopolymer bricks with a view of achieving a lighter weight construction
material.
Keywords: Coal ash, Eco-friendly bricks, Geo-polymerization, Waste plastic, Waste
materials