Statistical methods for determining rheological parameters of mortars modified with multi-walled carbon nanotubes

This paper investigates the influence of composition in the presence of multi-walled carbon nanotubes (MWCNT) on the rheological properties of mortars over the time. A rheometer Viskomat NT was used to assess rheological parameters, yield stress and plastic viscosity. On the basis of rheological results, a statistical model of composition variability on the rheological parameters of mortars in the presence of MWCNT was determined by the multiple regression method. The significance of the influence of variable factors and their interactions on parameter of yield stress and plastic viscosity was presented by means of ANOVA. It was found that w/c ratio has the most significant influence on rheological properties mortar modified with MWCNT, for both yield stress and plastic viscosity. For the yield stress parameter, immediately after mixing the ingredients, apart from the largest influence of w/c ratio, the impact is also shown by: amount of superplasticizer (SP), a combination of w/c ratio and SP, amount of MWCNT.