Investigation of the effect of colloid surface-active substances on the structure of building of fine-grained concretes

Abstract

Concrete is one of the most commonly used building materials, the volume of its production is quite significant. Taking into account that the monolithic method of building of buildings and structures is becoming more widespread, the demand for high-strength and especially high-strength concrete as well as concrete that can withstand rigid operating conditions is constantly increasing. In the manufacture of building structures and products, including monolithic, which operate under aggressive environments, as well as in the repair of reinforced concrete structures, the most effective use of fine-grained concrete. In order to increase the efficiency of concrete use, a great deal of attention is paid to the study of methods for improving the properties of concrete, in particular, for increasing durability, accelerating the periods of hardening, and adjusting the rheological properties of a concrete mixture. Such concrete should have certain specific properties, in particular high rate of formation of the structure, and, as a consequence, strength to shorten the construction time. The methods currently used to accelerate the hardening of concrete have significant drawbacks.  In particular, this applies to the use of surfactants. The purpose of this work is to determine the influence of aliphatic hydrophobic colloidal surfactant on the processes of hydration of cement when obtained fine-grained concrete. The results of these experiments showed that the introduction of "portland cement-water" into the disperse system of an aliphatic hydrophobic colloidal surface-active substance leads to an increase in the amount of bound water in the system. Also, a change in the structural strength of the cement paste with the addition of an aliphatic hydrophobic colloidal surfactant was investigated. As a result, it was found that the use of such a surfactant in the first hours reduces, and later increases the structural strength of the cement dough.  In addition, the change in the strength of concrete containing an aliphatic hydrophobic colloidal surfactant in time was investigated. It has been determined that the use of this surfactant is more effective than the use of other types of surfactants.