ESTIMATION OF DURABILITY AND DEFORMATION PROPERTIES OF CONCRETE AND REINFORCED CONCRETE
Authors:   Sumy National Agrarian University, Rogovyi S.І. , Tsyhanenko L.A. ,   Sumy National Agrarian University, Sribniak N.M. ,   Sumy National Agrarian University, Lutskovskyi V.M. ,   Sumy National Agrarian University, Tsyhanenko H.M. ,   Sumy National Agrarian University
Published: October 2021

Abstract. The research deals with the main directions of the Reinforced Concrete Theory current improvement on the basis of its incisive analysis. As leading direction in solving such a problem, the modern, well known deformational analytic model is examined. It is implemented on the base of complete experimental diagrams of deformation of different structural materials. The offered methods for improvement of such model suggest the creation and use of the transformed diagrams of deformation of concrete, reinforced elements as well as those structural elements on their basis. The modelling of these diagrams is envisaged on the basis of experimental dependences of complete diagrams for deformation of construction materials taking into account the influence on them of different physical, technological, dynamic and other factors. The general view of the said diagram will be realized by two its branches – ascending and descending, designed by different parametric (key) points. The special interest on the modern stage in development of deformational analytic model presents the design of descending branch of complete diagram on the state of construction material that is recorded by different parametric points. One of the main tasks in designing of such points is standardization of experimental methods in determining the critical values of relative power deformations in the top of a diagram, that correspond to the limit straining of construction material, that does not exceed the board of its durability at a compression. The descending branch of complete diagrams must be designed on condition that the deformation of concrete became consistently waning. The transitional point of this state in sustained and increasing deformation it to be considered as destruction start of material at intensively increasing destructive transformations of its structure. The straining of constructional material on such on-loading area of diagram can diminish to the level of postcritical values, beyond the durability range of stability at a compression, and to correspond to relative deformations in the limit state. Further reduction in tension to the concrete is representative at its dynamic deformation in terms of more intensive development of destructive transformations. Thus the level of relative deformations can increase to the maximally possible values, beyond which a concrete, as structural material, stops to comply with the necessary operating qualities. The long-term experience in initiation, perfection and development of theory of the reinforced concrete, as well as implementation of its modern deformational model of calculation show that there is a number of important vital problems which need to be examined and solved for today. Such problems in the outlined aspect are to be examined in two directions of researches. The first is an improvement of methodology of tests and standardization of methods in obtaining the complete experimental diagrams of the state and their parametrical points which allow to design dependence sb – εb (straining – deformation) with high authenticity by the analytical function for its implementation at the calculations of different structural elements; the second is an improvement of deformational calculation model with help of the transformed diagrams of deformation, as well as more precise definition of some pre-conditions and positions accepted in different existent standards for the calculation of concrete and reinforce-concrete constructions. The essence in solving of the above-said pressing issues set forth in this research.