Complex modifier based on alumina cement and pozzolanic addition

Abstract

Introduction. The most popular binders for the concrete production are inorganic binders. Composite binding agents (CB) based on Portland cement are increasingly being used to produce high-quality concretes, improve the efficiency of cement use in concrete, as well as to solve the problem of energy and resource saving by reducing the amount of clinker inthe cement composition.
 Materials and methods. The properties of a composite binder consisting of Portland cement, alumina cement, natural gypsum and an active mineral additive, were studied. The Box – Wilson experiment design method was used. To determine the standard consistency of the cement paste, the standard test method was chosen according to GOST 310.3–76.The research was carried out in the laboratory of the Department of Building Materials Science of Moscow State University of Civil Engineering.
 Results. It was found that with the introduction of additives normal density of the cement paste increases. This is explained by the fact that the composition of the complex additive includes tripoli and alumina cement. Tripoli is a natural porous rock with a highly developed surface. Alumina cement has a great influence on the normal density and setting time as it reacts very quickly to form new hydration compounds in the first minute from the start of mixing the binder with water.The dependence of normal density on the quantitative content of additives is presented as a regression equation and surface image.
 Conclusions. Based on the results of this study, in the future the authors will continue to study the properties of binders based on a complex expanding and pozzolanic addition.