Mechanical Properties of Hardened Geopolymer Concrete Mixes Including Nano Particles: A Comprehensive Review

The increase in global warming due to CO2 emissions from cement production is a critical problem, considering climate change these days. The alternative binder, instead of cement in the production of concrete, is to find a material that has the same chemical properties, is cost-effective, and is more sustainable than ordinary Portland cement, to mitigate the harmful CO2 impact on the environment and human beings. The primary objective of this research is to investigate the mechanical properties of various sustainable precursor-based geopolymer concrete (GPC) mixes, including those incorporating nanoparticles, in comparison to GPC without nanoparticles. This study aims to demonstrate a significant enhancement in the mechanical properties and durability of GPC, based on research conducted in this field. Different precursors were used in the production of GPC, including fly ash, metakaolin (MK), ground granulated blast furnace slag, and silica fume, which are the primary sources of alumina and silica. The nanoparticles used in GPC mixes are silica nanoparticles, carbon nanotubes, clay nanoparticles, alumina nanoparticles, and graphene oxide nanoparticles, each separately, to enhance the mechanical properties in different precursor-based GPC mixes. Moreover, the mechanical properties of hardened GPC, including nanoparticles, will provide compressive strength, tensile strength, and splitting tensile strength, among others. An optimum percentage of 0.35% nano graphene oxide and 2% carbon nanotubes, separately added to FA-based GPC, enhances the mechanical properties of GPC. The maximum limit for nano alumina is up to 3% for FA-based GPC, after which the mechanical strength will decline significantly. Furthermore, the maximum limit of carbon nanotubes is 2% in FA-based GPC, and then the strength will be reduced.