Anikanova T.V.

Candidate of Engineering Sciences (Ph.D.), Associate Professor, Belgorod State Technological University named after V.G. Shukhov, Russia

THE USE OF SEMI-AQUATIC CALCIUM SULFATE TO INTENSIFY THE PROCESSES OF HARDENING OF STRUCTURAL HEAT-INSULATING FOAMED CONCRETE

https://doi.org/10.34031/2618-7183-2018-1-3-25-32
Abstract
Construction of energy- and resource-saving housing of increased comfort involves the creation of more efficient building materials in comparison with traditional and new designs of fencing buildings with im-proved thermal properties. The problem of energy saving in construction has determined the direction of creation and production of effective cheap materials with high thermal properties. One of the most promising materials of this type is environmentally friendly, non-combustible cellular foam concrete.
The problem of accelerating the setting and hardening of foam concrete mixtures, as it allows to accelerate the turnover of forms and reduce the time from manufacturing to sending the finished product to the consumer is of great practical interest.
However, in most cases, domestic foaming agents are produced and used without additional input of setting and hardening regulators. This is due to the fact that the compatibility of the latter with the main additive – foaming agents is not sufficiently investigated. This problem is quite complex, as some setting accelerators can cause defoaming, worsen the structure of the foam matrix, reduce the mechanical strength of the stone and have other negative effects. At the same time, properly selected setting accelerators enhance the action of foaming agents
In the work the questions of application of semi-aqueous calcium sulphate (SCS) for intensification of hardening of foam concrete are considered. The change in physical and mechanical characteristics of foam concrete prepared on anionic and cationic blowing agents with an additional content of 1, 2 and 3% semi-aqueous calcium sulphate is shown. It is established that the SCC allows accelerating the hardening processes, and the formation of ettringite does not cause strong internal stresses, which is related to the porous structure of the material.
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THE EFFECT OF LONG-TERM STORAGE OF ELECTRIC STEEL SMELTING SLAGS IN DUMPS ON THEIR PROPERTIES

https://doi.org/10.34031/2618-7183-2018-1-1-32-39
Abstract
Сonstruction, repair and reconstruction of roads require high costs of mineral raw materials in the form of sand, gravel, mineral powder. However, its reserves on the territory of our country are distributed unevenly, which causes significant transportation costs for the delivery of mineral resources to construction sites. In addition, mineral resources are inevitably reduced over time, which requires extensive involvement in the construction of roads of non-traditional types of raw materials, as well as industrial waste.
The paper presents the results of studies of the properties of electric steel slag, the current output and stored in the dumps for several years. The main component of electric steel-smelting slags, both fresh and dumped, lying in dumps for about 20 years, is shannonite or γ-modification of calcium orthosilicate C2S. It has been established that the mineralogical composition of the Oskol Electrometallurgical Combine's slag is represented by hematite, wuistite, calcite, periclase, and also portlandite, formed during quenching of lime. Analysis of diffractograms of slags of different shelf life shows that in the initial periods of slag storage in the dumps there is a final quenching of lime and its carbonization with the formation of calcite. The results of the determination of the granulometric composition of the slag of different storage periods showed a decrease with time of the number of fine fractions and an increase in large fractions. It is established that when using electric steel-smelting slags in the construction and repair of highways, it is necessary to take into account changes in the physical and mechanical properties of materials. The processes that take place during the maintenance of slags in dumps determine the suitability of the use of slag mineral materials in road con-struction.
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