The results of optimizing the composition of concrete based on aggregates from crushed concrete are presented. With the help of mathematical and natural modeling matched the composition of the expanding agents sulfoaluminate type, the optimal percentage of components of the modified cement required for producing a material with improved performance characteristics, the mathematical model construction and technical properties of the concrete and the kinetics of their changes to take into account the time factor and strength and weathering.
Keywords: mathematical modeling, expanding additive, factor experiment, influencing factors, level of variation, experiment planning matrix
The article presents a program of comprehensive construction and technical expertise of the structures of an industrial building. The features of the construction and technical expertise of the structures of the agricultural warehouse of mineral fertilizers are described. An algorithm of the sequence of actions for the technical expertise of the structures of the object is developed. Measures have been developed to repair and restore the working condition of damaged structures
Keywords: construction and technical expertise, defects, bearing capacity, structural repair, property management
The task of identifying the properties of concrete and the location of damage in the layout structures of the beam type based on the application of experimental vibration analysis is considered. As a simple analysis model, beam constructions are defect-free and with defects. Based on the experimental approach, the model oscillations with shock and vibration excitation are analyzed. Based on analytical modeling, the dynamic modulus of elasticity, the speed of sound in the beam, the location of the defect are calculated. A technique and an example of determining the location of a defect in beam-type structures is presented. The article was published as part of the implementation of the program of the International Forum "Victorious May 1945"
Keywords: vibration diagnostics, identification, beam type construction, defect, experimental approach, analytical modeling, vibration excitation
The results of the investigation of the structure of the concrete, modified by the additive expanding, on the combined aggregate, which is a natural crushed stone mixed with crushed concrete, are presented. The study of the properties and regularities of the formation of the concrete structure is simultaneously a method of controlling their production. Regularities and reasons for the change (decrease) in the quality indices of concretes with a combined aggregate are established. Investigation and normalization of the properties of concretes on combined aggregates will allow using them along with traditional structural concrete.
Keywords: recycling, combined filler, contact area, structure, defects, durability
The results of a patent search in the direction of improving the design of crushing equipment are presented and a modernization option is proposed. Optimization of the parameters of the jaw crusher will prolong the service life, simplify the maintenance and repair processes, improve the quality of the secondary aggregate
Keywords: crushing, jaw crusher, aggregate of crushed concrete, modernization, optimization, lining, service life, reliability
The article presents the quality assessment of repair work for electricity pilons of transmission line performed by the method of vibration diagnostics. The suggested criterion for assessing the quality of the repair is relative adhesion of repair layers to the base of the stand. Modeling of structural oscillations strut mount, transmission lines and calculations in the finite-element complex Ansys. The dependence of the parameters own frequency of fluctuations of the value of damage at different values of the space adhesion. The resulting equations based on changes in natural frequencies on the magnitude of adhesion. The calculation of the relative adhesion of the repair composition to the concrete model of the design. The material presented can be used for assessing the quality of repair work of different structures of the core type reinforced concrete structures.
Keywords: vibration diagnostics, quality, repair of structures, defect, adhesion, natural frequencies
The article presents the algorithm of repair work for electricity pilons of transmission line.The technical diagnostics based on complex method includes a visual inspection, instrumental and vibration diagnostics for electricity pilons of transmission lines. Pilons has defects: inclined cracked faces with a length of 25-30 cm , with a crack width of 0,4-0,7 mm . Were selected effective repair compositions for restoring reinforced concrete structures rack transmission towers:modified fine-grained concrete, polymer concrete. The article presents an example of analytical modeling of natural vibrations of a reinforced concrete pilons of transmission lines with defects in the base. This article contains a list of repair works. The material presented can be used in the development of methods of diagnostics and monitoring of technical condition of different structures of the core type.
Keywords: Algorithm, repair, category of defects, non-destructive testing methods, pilons of transmission lines, vibrodiagnostics
The article presents the vibration diagnostics method for pilons of transmission lines. Pilons has defects: inclined cracked faces with a length of 25-30 cm , with a crack width of 0,4-0,7 mm . The article presents an example of analytical modeling of natural vibrations of a reinforced concrete pilons of transmission lines with defects in the base. Analytical modeling was based on the hypotheses of Euler-Bernoulli. Built an equivalent model of the pilons with defect in the form of an elastic element, simulating the damage in the area of trapping. The calculation of natural frequencies of first five modes of transverse oscillations for different values of stiffness of the defect. The result of this work is to obtain the dependencies of the relative frequencies from the stiffness of the defect and establishment of sufficiently informative criterion for predicting the alarm state of structures. The material presented can be used in the development of methods of diagnostics and monitoring of technical condition of different structures of the core type.
Keywords: vibration analysis, pilons of transmission lines, the defect, analytic modeling, transverse vibrations, natural vibrations, natural frequencies
Тhe analysis of methods and means of evaluation of technical condition of building structures under construction. The developed algorithm of a complex estimation of state of reinforced concrete structures with expired period of preservation. The algorithm of complex diagnostics of a condition of constructions involving complementation of known techniques of estimation of parameters of safety of structures with joint processing of the results, is an effective tool for assessing the actual condition of structures and end-of-life.
Keywords: safe operation, defect, nondestructive control methods, dynamic loading, vibration diagnostics, vibration sensors