INFLUENCE OF NANOMODIFIER TYPE ON CONCRETE STRENGTH

Abstract

Under certain conditions, an increase in the rate of hydration of the cement increases the strength of concrete at compression.  We studied the effect of surface-active substances, capable of forming micelles, on the rate of formation and the resulting magnitude of strength at compression of the concrete. A particular feature of our research was studying the simultaneous action of surface-active substance that forms micelles and polymer on the change in the strength of concrete. It was found that the specified micellar solutions polymer and surfactants without additives of other substances change the character of formation of strength of the concrete. The rate of strength formation over the early stages increases due to the micellar catalysis of hydration of cement, while their enhanced compressive strength is maintained at the late stages of hardening. Strength of the concrete, when adding the surface-active substances that form micelles, reaches 280 % of the strength of such concretes without any additives. It was proved that the micellar catalysis could be used to control the hardening processes of a concrete and to form the strength of the resulting artificial stone. That shortens the time required for concrete to achieve the designed strength and improves the absolute magnitude of the compressive strength of such concretes at the age of 28 days or more. It is established that the influence of surfactants on the strength of concrete exceeds the influence of solid nanomodifiers, in particular carbon nanotubes, micro silica, and others. When using aliphatic hydrophobic surfactants, which are capable of forming micelles, as separate modifiers of concrete, their costs are 10-4 ... 10-6 % by weight of cement. The increase in the strength of concrete at an early age reaches 90%, and at the age of 28 days - 40%. The mechanism of action of modifiers of this type and application is to structure the water due to hydrophobic hydration and the "low dose effect".