Study of dry mixes with aluminate cements for self-leveling floors

Abstract

In this article the results of the research of structure, shrinkage and physical and mechanical properties of concrete obtained from dry mixes based on aluminate cements for self-leveling floors are presented. The significant part of the cost of finishing works is the cost of mounting of the floors, as the quality of the floors determines not only the aesthetic comfort, but also the functionality of the room. The floors (especially, the floors of industrial, sports and so on buildings) must have the different properties: high strength and abrasion resistance, absolute resistance to cracking, dustless, hygienic etc. The main question of possibility of obtaining non-shrinking aluminate concrete is connected with the creation of ettringite using aluminate cement, gypsum and modern superplasticizers. Studies of free shrinkage of complex binder showed that binder could be classified as binder with compensated shrinkage. Cracking resistance of the composition is provided by the fact that the vast expansion in the initial stage of curing and shrinkage of the final stage is in 5...10 times lower than these values for gypsum and Portland cement. The problem of cracking resistance of thin-film coatings of cement compositions can be solved by binders with controlled shrinkage (expandable binders, whose shrinkage is compensated by the expansion). Resistance to cracking would be higher in the case when expansion and shrinkage are close not only in size, but also in the development time. The composition of dry mix for non-shrinking aluminate concrete consists of aluminate cement, gypsum, polycarboxylate superplasticizer and fractioned fine fillers. For experimental verification of the component composition of binder and the type of gypsum studies were conducted in a wide range of ratio of the components at a fixed value of the plasticity of the mixture. The structure of examined concrete is dense and has compensated shrinkage. Physical and mechanical properties of concrete are high enough and suited to the requirements of Russian construction norms (GOST).