Development of nanomodifiedrapid hardening fiber-reinforced concretes for special-purpose facilities
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2018, Vol 2, Issue 6
Abstract
<p>Experimental studies confirmed that the development of rapid-hardening concretes with high resistance to a high-velocity impact for special-purpose facilities is achieved through the multilevel modification of the structure. The introduction of dispersed fibers ensures optimization of a structure at the macro- and mesolevel. At the micro- and nano-leves ‒ by energetically active ultra- and nanofine mineral additives and a high-reducing polycarboxylate superplasticizer. We established high efficiency of the influence of an organo-mineral nanomodifier containing polycarboxylate superplasticizer, micro- and nano-silica on the workability of the concrete mixture and the kinetics of concrete hardening based on it. We detected a directional formation of the structure and the preset properties of concretes of highly flowing mixtures at both early and late stages of hardening. We established that the early strength of nanomodified concretes increases by 4.8‒5.1 times, and strength after 28 days ‒ by 2.0‒2.3 times. The study showed that an increase in the number of contacts, reduction in size and the number of initial defects and increasing the homogeneity of nanomodified concrete leads to the creation of a dense, fine-porous, less defective structure. Ensuring such a structure of nanomodified fiber-reinforced concretes leads to an increase in deformation characteristics, specifically stiffness and elasticity, which make it possible to withstand greater stresses at a constant value of relative deformations. We carried out tests on resistance of nanomodified fiber-reinforced concretes under conditions of action of a high-velocity impact that indicate their increased impact viscosity. Thus, we can argue about the relevance of a mechanism for the formation of regulated properties of nanomodified fiber-reinforced concretes and about practical attractiveness of the proposed technological solutions.</p>
Authors and Affiliations
Uliana Marushchak, Myroslav Sanytsky, Sergiy Korolko, Yuriy Shabatura, Nazar Sydor
Interlaboratory comparisons of the calibration results of signal generator
<p>The data of interlaboratory comparisons of calibration results of signal generators at three calibration points are presented. The choice of methodology for processing the results of interlaboratory comparisons is mad...
Establishing rational structural-technological parameters of the milking machine collector
<p>A collector of the milking machine is the nodal element in the system of accumulation and transportation of the received milk to a milk pipeline. It was established that the structural-technological parameters of the...
Application of systems approach at early stages of designinng unmanned towed underwater systems for shallow water areas
<p>Typical configuration of an unmanned towed underwater system (UTUS) was described and advantages of using this type of marine equipment for shallow depth works were outlined.</p><p>A list of basic operating modes of t...
Modeling a rheological anomaly in the system Na2O – SiO2 – NH3 – ZnO – H2O
<p>A universal calculation model for theoretical description of structural and physicochemical properties of aqueous solutions of modified silicates with the involvement of complexing agents is offered. The model takes...
Analysis of interaction between a configurable stone and a water flow
<p class="a">Erosion and destruction of riverbeds, foundations of flooded engineering structures are accelerated during natural phenomena, accompanied by a significant increase in the rate and wetted perimeter of river f...