The search for technological solutions for the organization of lean production at precast concrete enterprises was carried out. Options for rational use of rock crushing screenings as a filler and filler for self-compacting fine-grained concrete are considered. The optimal dosage of limestone crushing screenings in the composition of fine aggregate for the preparation of self-compacting mixtures has been determined. It was found that the enrichment of very fine Sands with large fractions of Sandstone crushing screening in an optimal amount reduces the intergranular voidness and reduces the water demand of the fine-grained mixture.
Keywords: lean production, rock crushing screenings, optimization of grain composition of aggregate, self-compacting fine-grained concretes, superplasticizer based on polyaryl and polycarboxylate esters
" The analysis of the influence of superplasticizers based on polycarboxylates on the formation of physical and mechanical properties of concrete under thermal influence. It is established that the high efficiency of the steamed self-compacting concrete with polycarboxylate-based superplasticizers is achieved at low-temperature modes of heat treatment. Rational mode of heat treatment of concrete should be assigned to the quality parameter established by the results of experimental studies. Article is published within implementation of the program of the International Forum «Victorious May, 1945»."
Keywords: construction materials producing industry, unburnt synthanite, apparatus with vortex layer, innovation, commercial soundness of investments, investment prospects, method of variation of parameters, uncertainty
Some approaches to assessment of soundness of investments necessary for implementation of results of research engineering are described. It is proposed to use the method of variation of parameters with the establishment of some restrictions. The results of the application of the proposed methodology are given on the example of evaluating the soundness of investments in the technology of unburnt synthanite from natural raw materials in the apparatus with vortex layer and the production of wall stones based on it. It is rational to use the proposed methodology in the formation of an investment plan, the development of business plans, and the implementation of graduate qualification work. Article is published within implementation of the program of the International Forum «Victorious May, 1945».
Keywords: construction materials producing industry, unburnt synthanite, apparatus with vortex layer, innovation, commercial soundness of investments, investment prospects, method of variation of parameters, uncertainty
The parameters of the thermal effect on the physical and mechanical characteristics of self-compacting concrete with the addition of fly ash Novocherkassk GRES. It was found that a higher level of quality SСС with the addition of fly ash is achieved at low temperature heat treatment. The duration of the thermal effect, which depends on the required Stripping strength of the concrete, should be assigned based on the specific production conditions. The effectiveness of fly ash in self-compacting concrete mixtures is manifested in reducing the water demand of the mixture and increasing the strength of concrete after heat treatment under the condition of rational dosage of hyperplasticizer and mineral additives. The optimum mode of heat treatment of SСС should be set by the coefficient of efficiency of heat treatment.
Keywords: self-compacting concrete, hyperplasticizer, mineral additive, concrete strength, heat treatment mode, heat treatment efficiency coefficient
The influence of polycarboxylate-based superplasticizers on the water-holding capacity of cements and the properties of highly mobile and self-compacting concretes has been studied. In the course of studies it was found that the water-holding capacity of cement in the presence of a specific additive reflects its potential activity and is a very important characteristic when choosing a pair of "cement-superplasticizer". Rheological activity of superplasticizer with cement concrete were estimated according to the value of the maximum shear stress of cement slurries. To assess the composition of self-compacting concrete should be used cement utilization factor in concrete, reflecting its technical and economic efficiency. Concretes with a rationally selected grain composition and dosage of polycarboxylate-based superplasticizers can achieve high strength with a minimum specific consumption of cement.
Keywords: water-holding capacity of cement, rheological activity of superplasticizer, self-compacting concrete, concrete strength, cement utilization factor
Provides a method of representation of the scheme of control and evaluation of concrete strength at the factory. The method does not require detailed text-th maintenance, differs with visibility and convenient for workers of the construction laboratories.
Keywords: Сontrol of the selling of concrete strength, the party of commodity concrete mixture, the party of the precast concrete and reinforced concrete, the required concrete strength