Characterization and mechanical performance of metakaolin-based geopolymer for sustainable building applications

[Display omitted] •Alkaline concentration imparts the mechanical behavior of MK-based geopolymer.•Curing temperature increases the kinetics of the geopolymerization process.•Fine aggregate may hinder the formation of more oligomers in geopolymers.•Addition of 5% Ca did not favor high compressive strength values of geopolymers.•Formation of new zeolitic crystalline phases influences geopolymer strength. Previous research has revealed geopolymer technology to be a promising alternate construction material to Portland cement. Existing data show that Portland cement material production contributes ~8% to the global CO2 emissions. This is detrimental to the environment and contribute to global warming. It is therefore pertinent to develop alternative cost-effective and environmentally friendly cement material. This study examined the performance of a Nigerian metakaolin-based geopolymer as a sustainable material alternative to Portland cement. Kaolin clay from Katsina State, Nigeria, was calcined at 700°C for 2 h prior to geopolymer processing. Different sample formulations of geopolymers were prepared in a 50 × 50 × 50 mm mold and tested in compression after curing at ambient temperature, 40 and 60 °C for 7 and 28 days. The geopolymerized specimens were characterized using XRD, FTIR and SEM techniques. Parametric study on the effects of the fractions of sodium hydroxide, sodium silicate, calcium hydroxide, fine aggregate and curing temperature on the geopolymer strength were examined. The results of the study revealed that Kankara metakaolin-based geopolymers can serve as a potential sustainable construction material for the Nigerian construction industry due to its availability, affordability, compressive strength values, and eco-friendliness.