Two-factor regression model of the strength of composite mortar with nano-additives

For the technological reliability of underground structures the method of obtaining composite mortars using alumin-containing nanotubes as structuring additives has been proposed It was found that in this case the duration of the loss of fluidity of the composite mortar in relation to the control sample is reduced by about three times. In order to ensure the industrial safety of underground structures the method of obtaining composite mortars using alumina-containing nanotubes as structuring additives has been proposed. The structural formation in the initial period in the composite mortars with different contents of boehmite and aluminous nanotubes in time has been studied. Optimal concentrations of additives are revealed, at which the rate of structure formation reaches maximum values. It was found that the introduction of aluminous nanotubes with the optimal concentration of 0.125% to the mass of cement accelerates the curing time of composite mortar in 1.3 times compared with the addition of boehmite. It was found that at the same time the duration of loss of fluidity of the composite mortar decreases relative to the control sample by about three times. Also, a two-factor regression analysis of strength for different concentrations of two materials: boehmite and aluminum nanotubes was carried out. Two models were built, for which we obtained: a type of function with a high coefficient of determination and determined the optimal material concentrations, at which the strength takes the maximum value.