Carbon fiber-reinforced metakaolin-based geopolymer composites
AssigneeNorthwestern University
InventorsAnge-Therese Akono, Jiaxin Chen
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Abstract
Methods for making carbon-fiber reinforced geopolymer composites are provided. The methods produce metakaolin-based geopolymer composites in which multiwalled carbon nanotubes and/or carbon nanofibers are well dispersed in an metakaolin-based geopolymer matrix. The mixing protocols of the methods used to produce carbon-fiber reinforced geopolymer composites produce composites with reduced porosity, high elastic moduli, high strength, and/or high fracture toughness.
Claims4
A carbon nanotube-reinforced geopolymer composite comprising:
- a potassium metakaolin-based geopolymer matrix;
- and
- multiwalled carbon nanotubes dispersed in the potassium metakaolin-based geopolymer matrix, wherein the concentration of the multiwalled carbon nanotubes is in the range from 0.55 to 1.5 weight percent, per weight of potassium metakaolin in the potassium metakaolin-based geopolymer matrix;
- the carbon nanotube-reinforced geopolymer composite having a porosity in the range from 5.5% to 7.5%, an indentation modulus in the range from 7.5 to 8.5 GPa, and a fracture toughness in the range from 0.58 Mpa·sqrt(m) to 0.65 MPa·sqrt(m),
- wherein the carbon nanotube-reinforced geopolymer composite is free of organic surfactants and organic dispersing agents and the multiwalled carbon nanotubes are not functionalized with surface carboxy groups.
A method of making a carbon nanotube reinforced geopolymer composite, the method comprising:
- forming an aqueous dispersion of multiwalled carbon nanotubes;
- ultrasonicating the aqueous dispersion;
- subsequently dissolving potassium hydroxide and silica in the aqueous dispersion to form a waterglass solution;
- adding potassium metakaolin to the waterglass solution to form a geopolymer solution;
- mixing and degassing the geopolymer solution in a centrifugal mixer;
- and
- curing the geopolymer solution with continuous mixing to form the carbon nanotube reinforced geopolymer composite,
- wherein the concentration of the multiwalled carbon nanotubes in the carbon nanotube-reinforced geopolymer composite is in the range from 0.55 to 1.5 weight percent, per weight of potassium metakaolin;
- the carbon nanotube-reinforced geopolymer composite having a porosity in the range from 5.5% to 7.5%, an indentation modulus in the range from 7.5 to 8.5 GPa, and a fracture toughness in the range from 0.58 MPa·sqrt(m) to 0.65 MPa·sqrt(m),
- wherein the carbon nanotube-reinforced geopolymer composite is free of organic surfactants and organic dispersing agents and the multiwalled carbon nanotubes are not functionalized with surface carboxy groups.
Dependencies are inferred from the claim text.