This paper is devoted to the study of the hardening process and the mechanical properties of composite cements. There were three mineral additions and two polymer ones, namely fly ash, limestone meal and marble powder, polymer dispersion and redispersible polymer powder used. The principal possibility of combining mineral fillers in the design of composite cements is shown. It has been established that the samples of cement stone based on binders modified with redispersible polymer powder have higher compressive and flexural strength, regardless of the type of filler.
Abstract. The peculiarities of the composition formation and hydraulic activity of high calcium fly ash got by burning of Kansk-Achinsk brown coals have been described. Fly ashes selected in dry state can be used as peculiar (specific) binding agents (minerals) on condition of their preliminary handling reducing nonuniform volume change of the ash stone during hydration and also the expansion range of their application in green building. The cavitation technologies, the organization of the fly ash granulation at heat power plants instead of hydraulic ash removal systems and enrichment by various means to extract rare-earth metals are considered to be the most perspective methods of fly ash conditioning.
An analysis of dense cements, such as polymer cement concrete, is made to produce original innovative components for different types of constructing materials. These materials present good functional properties (ageing resistance, crack formation resistance, hardness, and stability of mechanical modules) and can be used for various applications. In this paper, experimental tests on Portland cement with added γ-Al 2 O 3 and redispersible dry polymer performed using small angle neutron scattering are reported. The objective of the investigation was to assess the key parameters of the material (e.g., porosity, fractal dimensions, and size distribution) at the nanoscale level as well as to obtain useful structural information for expanding the possibility of applications. The results obtained can contribute to the optimisation of the consistency of the material, the design of operating conditions of elements of structures and facilities, and the design of the procedures that support ecological criteria and enhance quality and safety levels.
Study of dense cements, ceramics and related materials such as cement stones, is significant to create novel advanced components for various types of buildings and structures. These materials can possess high functional properties and they can be adopted for various purposes, for instance as corrosion resistive coatings for cement constructions. In this paper, the investigability of polymer cement concretes by neutron beam techniques (NBT) and, in particular, the nano-scale characterization by small angle neutron scattering (SANS) of polymer cement concrete (PCC) samples made of Portland or aluminous cement with added γAl 2 O 3 and redispersible dry polymer, are discussed. The main aims are to assess key parameters (e.g., porosity, fractal dimensions, size distribution, presence of cracks or open and closed pores) responsible of the materials' performance at the scale from 1 Å to 100 Å, as well as to expand the possibility of applications. NBT, among the other non-destructive diagnostics, are particularly unique in the complete analysis of industrial materials when supplying essential information. The results obtained by means of a neutron-based investigation can translate into the optimization of consistency and the design of operating conditions and procedures that support and enhance quality and safety levels. Various examples concerning the examinations of different kinds of cements are reported. This state-of-the-art stage indeed confirms the industrial applicability of NBT in completing the characterization of the considered materials.
The technology of power generation from nuclear power is accompanied by the formation of radioactive waste, which has significant potential environmental hazards. This paper proposes new methods of decontamination of NPP equipment with fluids that immediately after use can be converted into an environmentally safe condition -curing methods of decontamination solutions. A characteristic feature of curable solutions decontamination methods is that the composition of the decontamination solution, and also processes in the solution during deactivation, affect the subsequent transfer of this solution to a solid state, as well as on the properties of the matrix, which will be "sealed" removed radionuclides. The main factor determining the course of the process of decontamination methods can be divided into contact, acid-abrasive, ultrasound and combined. Concerning the main component of the decontamination solution (slurry) methods can be subdivided into solutions with hydraulic binders, clay slurry (with conventional clay and a clay with a high alumina content) suspension of diatomite and combined. The means of transfer of the solutions used in the solid state methods are divided into "self-curing" heat treatable and cemented. Application of methods of the curing solution allows us to reduce the number of operations to deactivate air conditioning that provides economic benefits and allows us to create a whole class of portable equipment and to reduce the amount ongoing to dump 4-6 times in comparison with cemented.
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