Characteristic properties of fly ash-based self-compacting geopolymer mortars with synthetic wollastonite microfiber produced from silica and calcite

This study investigated the fresh, physical, and mechanical properties of self-compacting geopolymer mortars (SCGs) with synthetic wollastonite microfiber (SWM). SCGs were designed with Class F fly ash (FA) as a binder by activating it with Na2SiO3 and NaOH solutions. First, SWM was produced in the laboratory. Alkali ratios were determined as 1.5, 2.0, and 2.5, whereas SWM percentages were utilized as 0%, 4%, 8%, and 12% by weight of the binder. After geopolymer mortars were cured at 80 oC and 100 oC for 24 hours, respectively, they were kept at room temperature until testing age. The compressive strength, flexural strength, ultrasonic pulse velocity, dynamic modulus of elasticity, water sorptivity coefficient values, and physical characteristics of SCGs were tested at the end of the 28th day. The highest compressive strength value was obtained as 28.9 MPa for SCG-1.5-8 cured at 100 oC, while 6.5 MPa was measured as the highest flexural strength for SCG-2-12 cured at 80 oC.