Sovgira Vasilisa, Sovgira Vasiliy
https://doi.org/10.35579/2076-6033-2020-12-13
ABSTRACT
The article presents the features of the process of the intensity of the development of destruction, pseudoplastic deformation and fracture of uniformly and inhomogeneously compressed heavy concrete with strength in the range fc,10 = 23,6; 40,8; 71,0 MPa [2...5 and others] and the marked difference in the intensity of the development of destruction, deformation and fracture of uniaxially compressed heavy, fine-grained and expanded clay concrete with strength fc,10 = 50,2; 54,9 and 36,9 MPa under the “soft” and “hard” loading conditions of uniaxially compressed concrete prismatic columns of the 5th standard size.
An analysis of literary sources was carried out with studies of changes in the elastic-plastic characteristics of vc, Еc sek heavy, fine-grained and structural expanded clay concrete taking into account the influence of significant factors and their change with increasing load when describing the dependence σc-εcх. It was found that the recommended by the Building Standards vcu , and Ес uniaxially compressed concrete quantitatively and qualitatively do not reflect the nature of the change in the elastic-plastic properties of heavy, expanded clay and fine-grained concrete (cement-sand matrix) of centrally compressed concrete with increasing load level.
Proposed analytical expressions of the dependence σc-εcх, describing experimental values of deformation diagrams of uniaxially compressed heavy, fine-grained (cement-sand matrix) and expanded clay concrete of series B with prismatic strength fc,10 = 50,2; 54,9 and 36,9 MPa of the investigated concrete samples of the 5th group of standard sizes with “soft” and “hard” loading conditions.
Studies are given that indicate that the mechanism of deformation and the process of development of destructions (decompression) of the structure of cement stone, heavy, fine-grained and expanded clay concrete with increasing load level affects the nonlinear nature of the change in the elastic-plastic properties: vc - coefficient of elasticity; secant modulus of elasticity Еcsek = Еc ∙ vc , which reflect the rheological properties of cement concrete in recommended expressions (1...3).
Analytical expressions are proposed for the dependence of changes in the elastic coefficients (vc) and the coefficient of developmental rate of destruction (KD) of uniaxially compressed concrete with an increase in the load level under the “soft” and “hard” loading conditions of the investigated series of cement concrete using: εсx; εсlx ; νсu ; νс , reflecting the process of changing the elastic-plastic properties of heavy, expanded clay, fine-grained concrete and cement stone in the ascending and descending sections of the complete diagrams of deformation of cement composites under central compression with a short-term static load.
Studies have noted that the intensity of the development of destruction in the structure of uniformly loaded heavy concrete is significantly (1,17 times) lower than in uniaxially compressed fine-grained (cement-sand matrix) and expanded clay concrete and 1,52 times less in cement stone.
The experiments established a characteristic arrangement of the levels of parametric points Ѳcх; fоcrс; fνcrс of heavy concrete with an increase in the load level of the investigated types of concrete, reflecting the intensity of the development of destruction of the structure of cement concrete.
Keywords: the intensity of the development of destructions; heavy, fine-grained and expanded clay concrete; uniformly and non-uniformly compression; loading mode; full diagrams.
For citation: Sovgira Vasilisa, Sovgira Vasiliy. Vliyanie intensivnosti razvitiya destruktsiy struktury tsementnykh odnorodno szhatykh betonov s vozrastaniem nagruzki na ikh deformirovanie i razrushenie [Influence of the intensity of development of destructions structure of cements uniformly compressed concretes with increasing load on their deformation and disruption]. In: Contemporary Issues of Concrete and Reinforced Concrete: Collected Research Papers. Minsk. Institute BelNIIS. Vol. 12. 2020. pp. 209-229. https://doi.org/10.35579/2076-6033-2020-12-13 (in Russian)
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ISSN 2664-567X (Online)
ISSN 2076-6033 (Print)
ISSN 2076-6033 (Print)