The article presents the analysis of the properties of local fine aggregates, their influence on the characteristics of the concrete, and also presents the impact of screening crushing when it is introduced into the mixture in various proportions on the strength of concrete
Keywords: Concrete, screenings of crushing, construction sand, experiment, grain composition, concrete strength, small aggregates
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
Due to the depletion of the natural base of non-metallic minerals used for the production of high quality aggregates for concrete, and also because of the significant damage to the environment when working sartirovochnyh crushing plants becomes relevant greater use of fine-grained concrete on local , not always of high-quality materials. Rostov region has large reserves of river small and very fine sand , not suitable for the preparation of concrete mixes. The article suggests ways to improve the quality of fine concrete local fine sands with the introduction of their composition from fine mineral filler (the TMN ), the role of which carry waste production and processing opal - carbonate- kristabolitovyh kremnizemistyh flasks Maslovskoye deposit Rostov region. Chosen route of administration mikronaponitelya and optimal dosage , to analyze the impact of THM on Water-solid, water-cement ratio and the strength of concrete .
Keywords: fine-grained concrete on fine sands, mill ground mineral fillers, mikronapolnyayuschy effect flask, gain strength