On the Determination of the Influence of Low Negative Temperatures on Deformability and the Development of the Microcracks Forming Process in Concrete Elements under Axial Compression

Abstract

Diagrams of axial, lateral and volumetric strains of concrete elements under axial compression in the conditions of low negative temperatures (in the frozen state) are built. It has been established that concrete specimens in the frozen state have increased strength and increased limits of axial, lateral and volumetric strains under axial compression. The diagrams of lateral strains coefficient are built. The dependencies connecting the changes in the values of coefficient of lateral strains of the concrete with variable parameters of its stress-strain state under negative temperatures action are investigated. Based on the analysis of change patterns in lateral, axial and volumetric strains, patterns of microcracks forming in concrete elements in a frozen state are established. The influence of low negative temperatures on the change of parametric points (levels) of stress-strain state of concrete, characterizing the lower and upper boundaries of microcracks forming regions is established. The results of these investigations are used for the development for the diagram method calculating of reinforced concrete structures, designed for use in conditions of low negative temperatures.

The Construction of the Diagrammatic Deformation Model for Calculating the Core Reinforced-Concrete Structures in Finite Increments under Joint Action of Load Increments and Variable by Cross Sections Low and Ultra Low Subzero Temperatures

“…Diagram methods of automated calculation and design" [5]. In [6,7,8] the development of the diagrammatic model and its diagrams is given in relation to the calculation of structures under the combined action of loads and low subzero temperatures.…”

“…We will multiply and simultaneously divide in the right part (10) the first curvature differences by In the overall relations (7), the pair of side coefficients is observed. It must also be observed in increments.…”