Investigating durability potentials of selected kaolin clays in Edo state, south–south region of Nigeria

The production of cementious material as a result of inorganic binders (geopolymer) being produced from aluminosilicate involving synthesized reaction with strong alkali solutions such as sodium silicates admixture by a poly-condensation reaction (geopolymerisation) between alumina and silica materials had greatly contributed to its use as alternative material and reduction in overdependence of Portland cement in Nigeria. The study aimed at the importance of reducing pressure on mining of non-renewable clay by concentrating on the qualities and grades of geopolymer produced using kaolin clays from Afor-okpella, Aforwa, Ossiomo and Ugbine kaolin clays in Edo state after subjecting each of them to optimal calcination process parameter (temperature): Afor-okpella: 600 °C,700 °C,800 °C,Aforwa: 600 °C,700 °C,800 °C, Ossiomo: 600 °C, 700 °C, 800 °C and Ugbine:600 °C, 700 °C,800 °C for which nearly complete dehydroxylation of the material and the durability properties the local material (kaolin clays) from Edo State geopolymer concrete will exhibit than normal concrete. By grounding Edo kaolin clays used, sieved to 212 μm and calcined at a temperature of 600 °C, 700 °C and 800 °C for six (6) hours. The geopolymers were synthesized using sodium silicate was (Na2SiO3) as the activating solution. The setting time, compressive strength (for 7 and 28 days), bulk density, water absorption capacity and apparent porosity test at the 28 day of curing was determined. The results for compressive strength of synthesized geopolymers for 7 days of curing were between 10.0N/mm2 to 19.0 N/mm2 and 13.8 N/mm2 to 25.6 N/mm2 for 28 days of curing high enough to be a useful Portland cement alternative. Meanwhile, the results of water absorption capacity was as low as 10.0% for 28 days of curing.Comparing the values with ASTM standards C6918-12, C216, C902 and C90 confirmed their suitability and durability for use as geopolymer materials and applicability to making geopolymer bricks and load bearing concrete masonry units.