The investigation of properties of metakaolin additive geopolymer material activated with NaOH

Metakaolin, produced by the calcination of kaolin clay and fly ash as one the industrial waste, which are pozzolanic materials, was used as raw material in this thesis. Alkaline activators such as sodium silicate and NaOH were used in the geopolymer production. The properties of the material were determined by carrying out chemical analysis and particle size analysis of the fly ash and metakaolin used in this study. 2.5 x 5 cm samples in the study are geopolymer pastes in which fly ash, metakaolin and alkaline activators were used. These samples will be formed in hydraulic hand press under pressure using cylinder metal molds. The samples were subjected to oven curing in a laboratory-type oven at different temperatures and times. Compressive strength values (one of the mechanical properties) of the geopolymer pastes were determined. The samples were kept in a water tank for 24 hours to determine the physical properties of all samples. Afterwards, water absorption, apparent porosity, bulk density and the apparent density values of the samples in question were determined. The data obtained from the paste samples indicates that porosity and water absorption rates decrease with an increase in curing time. The density values of the samples, on the other hand, increased depending on the curing time. The densest samples were found to be the geopolymer pastes subjected to curing for 24 hours. In conclusion, the compressive strength values of the geopolymer pastes varied between 8.4 MPa and 28.9 MPa. The apparent porosity values of the geopolymer pastes varied between 26.9% and 45.5%; the water absorption rate between 16.7% and 38.7%; the bulk density values between 1150.2 kg/m3 and 1612.4 kg/m3; the apparent density values between 2042.0 kg/m3 and 2328.6 kg/m3.