Repair technology features of main elements of road-building machines’ hydraulic system with use of polymer composite materials

Features of the operation and typical damages of standard hydraulic systems’ elements of road-building machines have been analyzed. The occurrence reasons of defects and the elimination ways of them were determined. Methods for eliminating the defects were analyzed, and it is shown that one of the most promising methods for eliminating the defects in liners of hydraulic cylinders and hydraulic lines is the use of polymer composite materials with a fibrous or dispersed filler for the repair.

INFLUENCE OF SULFUR MODIFICATION ON THE PROPERTIES OF SULFUR CONCRETE

The purpose of this study is the synthesis and study of modified sulfur concrete for use in industrial construction. To achieve this goal, sulfur concrete based on gossypol resin and pyrolysis distillate was modified and studied. The strength properties of sulfur-based concrete obtained from sulfur modified with gossypol resin and pyrolysis distillate were investigated. For the addition to sulfur concrete, industrial waste was used as a finely dispersed filler - fly ash from the Angren TPP and phosphogypsum generated at Ammophos-Maxam JSC. It was found that the best strength results correspond to sulfur-based concrete modified with gossypol resin using an additive in the form of phosphogypsum. The prototype characterized by low water absorption, high frost resistance in an aggressive environment (3% NaCl solution).

Investigation of the properties of composite materials based on epoxy resins with microsilica additives

The outcomes of studying epoxy-based composite materials supplemented with microsilica are provided in the article. Microsilica was used as a filler. The samples were produced on the epoxy ED-20 basis supplemented with 2, 5 and 10 mas. % of microsilica. The structure and size of finely dispersed filler particles were defined. The obtained composites were tested for resistance to the effect of variable temperatures, corrosive, and abrasion. The study outcomes proved that samples supplemented with 2% of microsilica are more resistant to acid and alkali as well as to petrol than those ones supplemented with 25% of microsilica. Besides the amount of the filler from 2 to 10% doesn’t sufficiently affect the resistance to variable temperatures. When microsilica is added to epoxy resin, it causes scuff resistance increase. The conducted testing proved that the developed composite materials are resistant to the effect of variable temperatures, corrosive, and abrasion. This enables to use these materials as coatings and anti-corrosion protection during machine maintenance.

Physical and Chemical Fundamentals of Building the Structure of Dispersed Filled Polymer Composite Materials and Nanocomposites

Questions of the construction of dispersed structures of polymer composite materials using a generalized model of dispersed filled polymer composite materials (DFPCM) are studied. Using the parameter of maximum proportion of filler (φm) allows you to take into account the size, shape, and distribution of part of the dispersed filler at the same time. The transition to generalized and specified parameters when describing the structure of the DFPCM leads to the possibility of highlighting the optimal criteria for obtaining systems with the highest strength characteristics. The transition to generalized and reduced parameters when describing the structure of DFPCM leads to the possibility of selecting optimal criteria that ensure obtaining systems with the necessary level of rheological, electrochemical, physico-mechanical and other characteristics.

SPECIFIC FEATURES OF THE FORMATION OF THE MICROSTRUCTURE OF GRANULAR AGGREGATES ON DIFFERENT BINDING COMPOSITIONS (PART 2)

This article is a continuation of the previous research. It includes analysis of the formation of the structure of granular aggregates during the hydration of the binder composition of BC-2 (PC 500-D0-N + 20 % quartz sand), prepared in a jet vortex mill. The study reveals the features of the dispersion of the quartz mineral filler (fractions ≤0.16; ≤0.315; ≤0.63 mm) and the main patterns of influence on structure formation at hydration of binders, differing in the composition and dispersion of particles. The paper analyzes physical and mechanical tests of the samples with the best strength characteristics and studies the features of their microstructures. The study of the microstructures of the samples reveals regularities, consisting in the formation of crystalline phases of different densities. It is noted that the introduction of 20 % mineral finely dispersed filler into PC 500-D0-N, in the form of quartz sand, ensures the formation of dense sub-microcrystalline hydrate phases when using a filler fraction ≤0.63 mm, which contributes to an increase in the additional strength of the samples by more than 20 %. It has been found that the mineral filler plays the role of crystallization centers, binding individual grains of fillers and sealing general structure of the composite. More compact healing of the pore space has been established for the composite with small crystalline new formations of hydrated calcium silicate

Design of compositions and types of structures of injection molded dispersed filled thermoplastics with good processability and high strength

The issues on the assessment of rheological properties of dispersed filled polymer composite materials (DFPCM) in terms of generalized parameters of disperse structure are considered. The dependences of pressure loss during injection molding of thin-walled DFPСM products with different types of disperse structure: dilute, low-filled, medium-filled and high-filled systems are given for the first time. It has been established that to obtain DFPCM based on thermoplastics with good processing properties and products with high strength, it is necessary to create materials having medium-filled type of structure and the generalized parameter Θ ≈ 0.5-0.6 vol/vol. The algorithm for calculating the dispersed filler content with known basic properties to provide a given type of DFPCM structure is proposed.

FEATURES OF THE FORMATION OF THE MICROSTRUCTURE OF GRANULAR AGGREGATES ON DIFFERENT BINDING COMPOSITIONS

This work includes a study of the microstructure of granular aggregates prepared on various binding compositions. The presented work includes three parts devoted to the analysis of the microstructures of granular aggregates taking into account the change in the percentage of the mineral filler in binding compositions. The article deals with the main aspects of the formation of the structure of granular aggregates during the hydration of Portland cement (PC 500-D0-N) and a binder composition (PC 500-D0-N + 10 % quartz sand) prepared in a vortex jet mill. The main regularities of the influence and dispersion of quartz mineral filler (fractions ≤0.16; ≤0.315; ≤0.63 mm) on structure formation during the hydration of binding components differing in the composition and particle dispersion are revealed. The paper analyzes physical and mechanical tests of the most promising samples with a study of their microstructure features. The study of the sample microstructures reveals the general regularities of the growth of crystalline phases of different densities. It is established that the introduction of 1 0% mineral fine-dispersed filler, in the form of quartz sand, contributes to the formation of sub-microcrystalline hydrate phases, which are centers of hydration, additionally binding individual grains of granular aggregates and compacting the structure of the overall system. In all samples, the formation of a block-rhythmic structure is observed, with the presence of individual block-aggregates. There is an overgrowth of microscopic pores with small crystalline neoplasms of calcium hydrosilicates. It is revealed that the structure of granular aggregates prepared on the basis of binder composition No. 1 (BK-1) has higher density than on Portland cement PC 500-D0-N.

Method of Metallurgical Production Waste Processing

The modern development of the construction industry needs to find ways to create new competitive materials. Such materials are polymer composites, since the range of their application can be wide, due to the possibility of regulating their technical properties. This work presents a research on the development and production of polymer composites and products from them with the improved mechanical properties by adding finely dispersed techno-genic mineral raw materials as a functional filler. As a dispersed filler of the polyvinyl chloride composition, waste from the production of refined silicon was used, which is dust from the entrainment of furnaces captured by an electrostatic precipitator. To predict the characteristics of the materials obtained, the applicability criteria of techno-genic raw materials in the polyvinyl chloride composition are studied. Studies of the mechanical and operational properties of the obtained composites have confirmed the possibility of using techno-genic raw materials as functional fillers that affect the mechanics, durability, and also significantly reduce the cost of finished products.

The molecular mobility of the epoxy binder in a modified composites by electric-hammer

In this work, the study of molecular mobility in the surface layers by the method of determining the dielectric characteristics of materials modified by electrospark hydraulic shock, determined the optimal content of the dispersed filler. Comparative data of the tangent of the dielectric loss angle of treated and untreated composite materials are presented.