Patent ID: 8865107

Claim:
A method for producing reinforced cement-based materials comprising a concentrated suspension of multiwall carbon nanotubes (MWCNTs), comprising the steps of: (a) providing a first solution, said first solution comprising water and surfactant; (b) creating a second solution by dispersing said MWCNTs in said first solution, wherein said second solution has a first UV-vis-NIR absorbance value, and wherein the concentration of MWCNTs in said second solution is less than or equal to 0.16 weight %; (c) creating a third solution by ultracentrifuging said second solution, wherein said third solution comprises a concentrated portion and a non-concentrated portion, wherein said concentrated portion has a second UV-vis-NIR absorbance value, and said second UV-Vis-NIR absorbance value is between 3.13 and 4.87 times said first UV-vis-NIR absorbance value; and (d) removing said non-concentrated portion from said third solution to create said concentrated suspension of MWCNTs.