Open AccessPHENOMENOLOGICAL ANALYSIS OF THE ROLE OF GEOMETRIC FEATURES IN THE FORMATION OF THE STRUCTURE AND PROPERTIES OF THE MATERIAL
Author(s) -
Александр Викторович Колесников,
S.V. Semenova,
G.A. Kirilenko
Publication year - 2021
Publication title -
vìsnik odesʹkoï deržavnoï akademìï budìvnictva ta arhìtekturi
Language(s) - English
Resource type - Journals
ISSN - 2415-377X
DOI - 10.31650/2415-377x-2021-82-73-81
Subject(s) - materials science , phase (matter) , structure formation , mechanism (biology) , phenomenological model , composite number , stress (linguistics) , pattern formation , composite material , chemical physics , mechanics , chemistry , physics , condensed matter physics , linguistics , philosophy , organic chemistry , quantum mechanics , galaxy , biology , genetics
Abstract. The paper discusses the reasons for the decrease in the strength of the composite material in relation to the theoretical. A hypothesis is put forward according to which, along with the known reasons; in particular, the presence of internal interfaces, and together with them, the processes near the forming geometric features that arise during the structure formation of the binder paste can act as reasons for the decrease in strength. To simulate the occurrence of features in composite binder paste, the concept of the local formation of new growth on the nuclei of a new phase present in the binder paste ‒ layers of a hydrated binder on the surface of its grains ‒ is used. According to the proposed model, the growth of a new phase occurs according to the mechanism associated with the formation of a wave front. The wave front also undergoes metamorphosis, as a result of which its features are formed, near which structural defects are concentrated. Another type of geometric features is hidden interfaces, which are formed as a result of opposite growth of wave fronts and their contact. The proposed mechanism is confirmed by the data of a microscopic study of the processes of structure formation of a gypsum binder ‒ the formation of contact surfaces of the crystalline phase with different geometric and structural properties is observed on a model sample. As one of the main reasons for the occurrence of high concentrations of microcracks and other stress concentrators near hidden interfaces of the two types, the coexistence of solid phases with different structural characteristics in these regions is considered (there is a mismatch of the structural order parameters near the forming interfaces), as a result of which the strength decreases. This fact also explains the observed decrease in the ordering of the structure of the material in these areas. On the basis of the considered mechanisms of the formation of structural features leading to the destruction of the sample, methods are proposed for controlling the formation of the structure of the material, in particular, the targeted local introduction of solid phase nuclei into the binder paste.