-Theoretical foundations and the results of preliminary experimental studies related to the design of the heat insulation plastering material are considered. The main problem is to provide heat-insulating properties and strength characteristics of the appropriate level required. The solution is based on the percolation theory, allowing to determine the proportion of thermal insulating filler to interrupt most of thermal paths, and ideas of structural optimization, allowing to increase the strength of the material due to the selection of particle size of the basic components -gypsum and perlite powder, as well as by the introduction of mineral and organic additives. Methodological techniques developed in the implementation of these directions are applicable for other tasks of building materials science.

В статье рассматриваются методические приемы синтеза энергоэффективных строительных композиционных материалов на основе методов теории перколяции и структурной оптимизации.Основная проблема, возникающая при проектировании материала, заключается в обеспечении требуемых теплоизоляционных свойств и прочностных характеристик. Для ее решения используется теория протекания, позволяющая определить долю теплоизоляционного заполнителя, при которой прерываются основные пути распространения тепла, и идеи структурной оптимизации, позволяющей увеличить прочность материала за счет введения структурообразующих минеральных и органических добавок. Введение активных добавок способствует частичному разрыхлению структуры и раздвижке частиц, улучшают условия гидратации вяжущего. Методические приемы, разработанные при реализации этих направлений, применимы для других задач строительного материаловедения.

This paper presents the research method of hardening process of gypsum binders and composites, based on them, using the ultrasonic method. Modern construction composites, based on higher water resistance gupsym, contain the coarse aggregate particles, giving them heat and sound insulating properties. One of the frequent purposes, designing such composites, is the slowdown of the processes of setting, so it allows the builders to work with the material for a sufficiently long period. The use of standard control penetration methods of the setting processes for the considered composites becomes difficult because of the presence of course particles in the binder paste. The ultrasonic method is proposed to use alternatively to study the process of setting. For its implementation, the technique has been developed, based on the use of ultrasound systems for quality control of concrete products. The transit time of ultrasonic signals through the layer of hardening binder paste with the fixed thickness was measured in a regular intervals until completely setting. On the basis of the obtained data, the ultrasound velocity was calculated and the setting time was determined. For this purpose, a differential curve of the time of ultrasound transmission was plotted, and the period was considered, at which the transition to the steady-state condition was carried out, it is equivalent to the end of the setting. The initial setting was determined by the first trip of the measuring equipment, corresponding moment of the formation of the primary crystal structure of the composite, which has sound-transmission properties. To verify the values of the setting time, the simultaneous measurement of the plastic strength of the model system was used. The moments of the beginning and the end of the setting, as well as the ultrasound velocities which were typical for these moments, were determined with the plastic strength. The obtained velocity values allowed to find the setting times of other composites. The actual setting time is estimated based on the values, obtained by all the available methods. The model, based on percolation theory, has been proposed for analyzing the physicochemical phenomena during the setting.

No abstract

The paper describes the methodology of processing of the experimental data from the study of the hardening process of the binder paste, which allows to reveale information hidden in the results and objectively divide the period of structure formation into steps that differ in mechanisms and conditions. The proposed method has a universal character, is designed to study compositions of a heterogeneous structure and is implemented using experimental data on the plastic strength of gypsum binder paste as a simplified model of such a composition. It consists of two stages - the transition to normalized values and coordinate transformation to adequately display the observed processes of structure formation. To determine the type of the corresponding coordinate transformation, Erofeev and Kolmogorov equations were considered, which describe, in particular, crystallization processes. Based on the proposed equations, a physically reasonable choice of coordinate transformations of the re-logarithmic type was carried out. Processing the data on the plastic strength of the hardening gypsum binder paste as a model of the composition of an inhomogeneous structure allows us to identify the main stages of structure formation characterized by linear dependencies and transition stages in which qualitative transformations of the regime of change in plastic strength during hardening are observed. The separation of the total time of structure formation at the step is fixed on the graphs of changes in the corresponding properties, and the transition stages correspond to the points of change in the angular coefficients of the obtained dependencies. It is shown that the stationary step of structure formation corresponding to the stable maintenance of supersaturation is reflected in the general linear section on the graphs. It is shown that the time of occurrence of transition stages recorded during the measurement of plastic strength approximately corresponds to the setting time obtained by regulatory methods. A geometric interpretation of the angular coefficients of the obtained dependences which allows one to determine the structure of growing nuclei of a new phase was considered. The proposed technique can be applied to control the processes of structure formation of heterogeneous composition compositions.