metakaolin

This paper presents the properties of fresh and hardened self-compacting concrete (SCC) containing supplementary cementitious materials, such as complex sulphoaluminosilicate additive based on the metakaolin and gypsum, fly-ash and limestone microfiller. If sufficient gypsum is present the main hydration products in unclinker part is a thin crystals of ettringite. Ettringite is formed by a topochemical reaction in a closed space at the beginning of the formation of the cement matrix, which ensures the compaction of SCC.

The development of high-performance materials, which are characterized by high compressive and flexural strength, durability and performance properties, is an urgent problem of modern construction. Engineered cementitious composites are one such material. Improving of properties of composites is achieved by partial replacement of cement with supplementary cementitious materials. The ratio of binder and filler components and superplasticizer consumption were selected.

The paper presents the results of research concerning the peculiarities of modern High Performance Concretes based on cementitious systems "Portland cement – active mineral additives – micro fillers – superplasticizers – accelerators of hardening". Physico-chemical regularities of structure formation of super plasticized cementitious systems are established.

In the article the features of reinforced concrete hardening at different temperature conditions and the current issues of preparation technology of Self-Сompacting Сoncretes (SCC) on the basis of superplasticized cementitious systems, combining knowledge of structure and modifying Portland cement compositions "Portland cement – active mineral additives – microfiller – superplasticizer – accelerator of hardening" to search for rational making provision of technical and building properties of concrete in the changing factors of its composition, technology and exploitation are shown.

One of the leaders of wall materials in the modern market, which combines high constructional and thermal insulation properties, is cellular concrete, in particular non-autoclave hardening. Improving efficiency of cellular concrete as a heat insulating material is, above all, in the maximum possible decrease in average density, while providing a certain level of physical and mechanical indicators necessary for the manufacture of products in the form of slabs.

One of the actual problems of the further sustainable development of construction industry is solution of energy and resource saving problems during production and reduction of harmful emissions. Building materials based on gypsum raw compared to cement materials of analogical purpose are characterized by low energy consumption, as well as better ecological indicators. However, gypsum materials without modifying additives have low strength and water resistance which limits their application to the area of internal processing of rooms with a relative humidity of up to 60 %.

The development of the technology of new binders and concrete involves the following stages: the selection and preparation of materials, designing the composition in accordance with requirements, preparation of the mixture and the formation of products, initial curing and setting, further hardening. All these stages are united in a single complex, in which each stage has its own special significance and simultaneously affects the efficiency of the entire technological complex.

A study of the rheological properties of self-compacting fiber reinforced concrete mixtures with additives of modifiers and microfillers and performance characteristics of concrete based on these mixtures has been carried out.

Investigations concerning the processes of plugging stone structure formation, using X-ray diffraction, electronic microscopy and differential thermal analyses, were implemented. Influence of active mineral additives of metakaolin and zeolite on the properties of plugging mortar and their interaction with Portland cement minerals with the aid of the model systems were established.