DAMAGE OF CONCRETE STRUCTURES DURING PERIODIC WETTING AND DRYING

Abstract

Material structures resist the destructive effects of the external environment by compensating transformations of the structure of the material from which they are made. This necessitates the analysis of structural elements of concrete, capable of responding in a timely manner to external influences, taking into account the multivariability of its structure at the macrolevel. Self-support of structural stability of concrete under the influence of external factors is determined by the possibility of redistribution of responses of its structure, which, in turn, depends on a set of macrostructural parameters. The originality of the approach to setting and achieving the goal of research is to present the macrostructure of concrete as an interconnected set of structural cells formed by fillers in the matrix material. It is assumed that real concretes include the entire possible set of macrostructural forms. The parameters of each cartridge determine their own conditions for the processes of structure formation and implementation of the properties of the matrix material. This is confirmed by the difference in quantitative values ​ ​ of volumetric deformations and the duration of hardening of solidifying systems in models of structural cells. Technological damage, water absorption and compressive strength of models of concrete samples also change, on average up to 2 times. After cyclic moistening and drying, the damage of the samples with various methods of laying and orienting the aggregates changed up to 24%, and with a change in the state of the surface of the aggregates - up to 19%. The influence of structural differences on the behavior of the material is preserved at each cycle of interaction of the structure with the operating environment. Therefore, when assigning concrete compositions, it is necessary to take into account the diversity of the structure of the material of the structures to improve the safety of their service.