Abstract:
The reuse of waste materials can help to solve problems relating to placing them
in landfills and can be a step towards environmental sustainability by decreasing the
production demand of cement for concrete. The use of Geopolymer concrete is one of
the possible solutions that is rapidly gaining popularity among researchers In this
study, an attempt has been made to produce fly ash based geopolymer concrete using
recycled waste materials replacement such as slag and quarry rock dust for
construction. Four geopolymer concrete composites including normal concrete mixture,
fly ash based geopolymer concrete containing 5% cement, fly ash and slag (1:1) based
geopolymer concrete and fly ash, slag, and rock quarry dust (1:0.9:0.1) based
geopolymer concrete were produced. Sodium hydroxide with molarity of 14 and sodium
silicate solutions were used as an alkaline activator in this research.
The mechanical properties of the concrete composites were evaluated by
conducting compressive strength test, tensile strength test and flexural strength test. It
was found out that 50% fly ash, 45% slag & 5% quarry rock dust based geopolymer
concrete cured at higher temperatures of 65 C showed an increase of 8% compressive
strength at 28 days when compared with that of control mix of 28 days, whereas FGPC
with 5% cement admixture showed an increase of 16% in 28 days compressive strength
form the control mix. Similarly, the 28 days flexural strength of 50% fly ash, 45% slag &
5% quarry rock dust based geopolymer concrete was slightly higher than FGPC with 5
% cement as an admixture and 4 % down in flexural strength with that of control mix at
28 days. Cost analysis for all sample, which indicates that the sample composed of 5%
Cement + GPC has the lowest cost among all the batches and almost 25% less than
OPCC. Although all batches have the same size. Moreover, the 5% QRD + 45% Slag
& 50% FA cost is 15 - 18% less than OPCC. After comparing all batches having different
composition, it becomes evident that the 50% FA + 50% Slag is 10% cheaper than
OPCC.
TA
