CONCRETE CRACK RESISTANCE CONSIDERING DESTRUCTION MECHANICS (REVIEW)

This paper presents the generalized results of the analysis and synthesis of scientific and technical sources of investigation the heavy concrete on the basis of fracture mechanics for the last 25-30 years. New criteria and models for heavy concrete, which were obtained during this period have been described and generalized, in particular, a new deformation model of concrete crack resistance on the basis of fracture mechanics. The analysis of results of experimental and theoretical researches of heavy concrete crack resistance on disk-shaped samples at eccentric stretching by concentrated forces has been presented.  A number of methods have been elaborated i.e. a method for experimental determination of the concrete crack resistance characteristics under static loads, a method for determining the length of the fracture zone in the crack, the relationship between the mechanical characteristics of heavy concrete and the parameters of acoustic emission measurement. The method of concrete cracking resistance with the addition of basalt fiber was also developed and the influence of basalt fiber on crack resistance and crack opening was studied in field tests. The generalized results have been presented. It has been stated about the significant development over the last three decades of methods for determining the strength, crack resistance and deformation of concrete in reinforced concrete elements from the standpoint of reinforced concrete mechanics and mechanics of concrete destruction. The conclusions about the expediency of using the Leonov-Panasyuk deformation model for concrete and the prospects for fictitious crack model have been made. On the basis of the generalized data given in the specified publications the technique of technical diagnostics and a technique of repair and restoration works at strengthening with use of modern technologies and materials has been developed that gives the chance to increase considerably a resource and reliability of reinforced concrete buildings and constructions.