Mechanical Properties of Ultra-High Performance Geopolymer Concrete: Effects of Quartz Powder and Silica Fume

This study investigates the mechanical properties of silica fume and

quartz powder ultra-high performance geopolymer concrete.In the

designed geopolymer concrete mixtures, ground blast furnace slag

(GGBFS) as binding material, silica fume (SF) for rapid strength gain

of geopolymer concrete, quartz powder of 0-0.05 mm and 1-3 mm diameters

as aggregate, and sodium hydroxide (NaOH) and sodium silicate (Na2SiO3)

as alkali solutions were used. In the mixtures, a constant volume ratio

of 29.9% and 14.9%, 0-0.05 mm and 1-3 mm diameters of quartz were

used, respectively. In addition, a total of three different geopolymer

mixture designs were made as 2.1%, 4.2% and 6.4% silica fume.

Geopolymer mixtures were kept in curing environments at 60℃ for 4, 6

and 8 hours. Physical, mechanical and capillary water absorption

properties of geopolymer samples with different mixing ratios were

determined experimentally. The test results showed that the highest

compressive strength was 97.9 MPa and flexural strength was 9.4 MPa

in the mixture with the lowest silica fume and kept in the curing

environment for 8 hours. In addition, it was determined that the lowest

capillary water absorption value was 0.43 kg/m2 and the lowest dry

unit volume weight value was 2203 kg/m3 in the same mixture.