Fly ash based geopolymer concrete For marine structure application: Resistance to sulphate attack

The world becomes increasingly ocean-oriented for energy and other resources. It is
predicted that concrete sea structures will dominated construction activity for the next
century. Marine environment can be considered as harsh environment for concrete
durability. One of the most serious problems concerning the durability of concrete is
sulphate attack. Ordinary Portland Cement (OPC) has dominated the world of
construction as most used material due to its economical and durability reasons.
However, cement industry contributes 5% of global carbon dioxide emissions.
Therefore, in order to reduce CO2 emission hence slowing the global warming, an
alternative has been developed which has stronger durability, utilized industrial waste,
and environmental friendly during its production. The alternative is called fly ash
based geopolymer concrete. In this project the potential of geopolymer replacing OPC
is tested by determining its durability in marine condition. NaOH and KOH are the
activating materials used with different concentration including 4M, 6M, 8M,10M,
and 12 M. The geopolymer also cured in two different temperature 25°C and 60°C.
The specimens are exposed to 5% sodium sulphate (represent the marine environment)
for 14 days.