Investigation of the effects of alkaline activators and sand type on the properties of calcined zeolite-based geopolymer

Abstract This study examines the effects of sand type on the properties of the calcined zeolite-based geopolymer mortars. The geopolymer mortars were prepared using different sand types, standard and crushed, in different ratios. The zeolite calcined at 600 o C was used for the alumina silicate resource. The sodium hydroxide at 4 M, 8 M, and 12 M and sodium silicate solutions with 2Ms and 3Ms were used for the alkaline activation process. Using a vibrating table, the prepared geopolymer mortar samples were placed in a 40 × 40 × 160 mm metallic mold. The samples were then cured in the oven at 90 o C for 6 h. According to the results, the geopolymer mortars’ apparent porosity and water absorption values varied depending on the NaOH molarity and the sand used in the mixtures. The apparent porosity and water absorption rates varied in between 11.85 − 25.54% and 7.02 − 16.51%, respectively. Considering the data obtained from the geopolymer mortars activated with different NaOH molarities and SS solutions, the flexural strengths are between 0.93 MPa − 4.0 MPa, and compressive strength values are 3.39 MPa − 12.54 MPa. The highest flexural (4 MPa) and compressive strength (12.54 MPa) were obtained in the CS40 samples. As a result, the increased amount of crushed sand content increases the strength values.