The determination of the rational parameters of a vibration machine for the internal compaction of concrete mixtures. We researched the “vibration machine – concrete medium” system wherein the concrete medium is represented by a system with distributed parameters that takes into account the resilient, viscous, inertial and energy properties of the compacted concrete medium. We researched the propagation of the viscous-resilient-plastic deformation waves in the contracted concrete mixture represented in the form of a half-space. We determined the amplitudes of the oscillations and stresses occurring in the compacted mixture depending on its physical and mechanical characteristics. We determined the oscillation amplitude of the vibration machine, identified its rational parameters. We determined the regularity of the motion of the compacted mixture and the vibration machine depending on the physical and mathematical characteristics of the compacted mixture, the thickness and width of the compacted layer, the angular oscillation frequency and the amplitude of the exciting force. The presented dependences enable the substantiation of the rational parameters of the vibration machine and the modes of vibratory action.
Purpose. The creation of the compacting vibratory process theoretical basis enabling the assessment of the efficiency and the choice of rational modes of the vibration influence on the concrete mixture, based on the minimal energy input in the process of its compacting. Methodology. The paper contains the description of the mechanism of compacting under the action of external vibration forces whereat a variable tensely deformed condition occurs in the concrete mixture. In this case the primary structural links break, the links between its separate elements weaken, the final movements of mineral particles result in the creation of a more compact packing. As the basic factor determining the character of the compacting process, the authors propose to use the product of voltage and the velocity of the vibratory action, which presents the power of the vibratory action on the compacted medium. Results. The authors have obtained analytical expressions enabling the determination of the growth of the concrete mixture density in time function depending on the type of the vibratory load and the power of the applied vibratory action on the compacted medium. The paper contains the theoretical and experimental values of the specific work that provides compacting up to the values required by the technological norms depending on the consistence of the concrete mixture at vertical and horizontally directed vibrations. Conclusions. The authors have specified the existing hypothesis and proposed a more general power hypothesis of the process of vibratory compacting of concrete mixtures, applicable to the description of the vibration process and concrete media treatment by various vibratory mechanisms, tools and machines. One can use the obtained results to set the rational modes and duration of the vibratory action on the compacted medium depending on the amount and type of the specific work of compacting and also to determine the basic parameters of vibration machines of various technological purpose.
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