![]() ![]() ![]() Please click here to view License Agreement for Educational Institutions. If you do not agree to the terms of this License Agreement, promptly exit this page This License Agreement, that you understand it and that you agree to be bound by its IMPORTANT-READ THESE TERMS CAREFULLY BEFORE DOWNLOADING THIS DOCUMENT.īy downloading the ASTM Document you are entering into a contract, and acknowledge that With further study and refinement, it offers promise of providing a reliable estimate of the cement content of hardened concrete within the precision of construction and sampling. It is concluded that the microscope analysis is at least as precise as the chemical methods, and that it requires less time and equipment. The precision of each method is estimated, and the advantages and limitations are discussed. Comparisons are also made with results of chemical analysis according to ASTM Method C 85-54 and two other chemical methods developed during the investigation. Results of microscope analysis of various laboratory-mixed concretes are compared with original mix proportions. The voids and aggregate content are estimated by direct observation the cement content is then determined by difference, with correction for non-evaporable water in the cement paste. This paper describes a “point-count” method of determining the cement content of hardened portland-cement concrete by analysis of a cut section with a traveling microscope. Existing methods of chemical analysis depend heavily on knowledge of the chemical composition of the aggregates, which is seldom available. This should be manifested in checking the equation of absolute volumes for the original and compacted (dewatered) concrete.Determination of the proportions of materials in hardened concrete in structures becomes desirable when question arises as to the quality of the concrete actually placed. The previously developed technological conditions for forming concrete pipes, in addition to the above, require, when assigning the composition of concrete, to take into account the observance of the balance of masses in the concrete mixture and compacted, modified concrete. Obviously, the listed volume of initial information comprehensively characterizes the materials used and the conditions for forming the product. For the experimental study, a total of six independent information streams of initial data are used: 1-physical and mechanical properties of the constituents of concrete ( R c, ρ c, ρ c°,, р с, γ 3, ρ shch, γ sh, γ shch°) 2-laboratory data of tests of raw materials in concrete mix and concrete (a, b, c, Ku, A, B) 3-design characteristics of concrete mix and concrete ( R b, F, W, OK, Z h) 4-characteristics of the product to be concreted ( V, h, l, μ) 5-technological characteristics of equipment, mechanisms, and devices ( th, tb, TO, t0) 6-the cost per unit volume of raw materials ( Sc, Cn, Ssh, Se, Sg). The necessary data for the assignment of concrete compositions are determined according to the data of preliminary laboratory experiments, the given technological parameters of mechanisms and equipment, and the design characteristics of concrete and the structure to be formed. Distinctive features of the method are the use of a large amount of information and the absence of arbitrary coefficients, technological constants, or parameters. The accepted conditions are necessary and sufficient when using the physical-analytical method of designing concrete composition. * Corresponding author: choice of the concrete composition following the set research tasks must satisfy the following requirements: 1-the maximum achievable strength on the given starting materials 2-the required formability, corresponding to the accepted vibration-impact-peristaltic pressing 3-a given level of dehydration of the concrete mixture, providing a residual W/C, close to the normal density of the cement paste. Petersburg, Russiaģ Academic Lyceum "International House Tashkent", Tashkent Institute of Irrigation and Agricultural Mechanization Engineers, Tashkent, UzbekistanĤ YEOJU Technical Institute in Tashkent, Tashkent, Uzbekistan Bakhridin Khasanov 1 *, Ruzimurot Choriev 1, Nikolai Vatin 2, Zukhra Ismailova 1, Alisher Tillaev 3 and Timur Mirzaev 4ġ Tashkent Institute of Irrigation and Agricultural Mechanization Engineers, Tashkent, UzbekistanĢ Peter the Great St.Petersburg polytechnic university, St. ![]()
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