strength

This article examines the effects of the simultaneous action of sodium chloride and cyclic freezing and thawing on the strength of monolithic road concrete of varying strength classes. There are two methods for protecting concrete and ensuring its durability. Primary concrete protection involves the proper selection of materials and ensuring their optimal ratio. Secondary protection involves treating concrete with special impregnating compounds based on organomineral compounds.

The influence of the nature of the fillers based on polyvinylpyrrolidone and precipitated sodium liquid glass on the morphology and properties of polypropylene has been established. The modification of polypropylene with polymer-silicate fillers contributes to a change in the morphology of the composites, in particular, an increase in the degree of crystallinity and a decrease in the average size of crystallites are noted.

Problem statement and research purpose. The improvement of the pressure plate drive mechanism of a flat die- cutting press, which ensures strictly vertical movement of the pressure plate during the working and return strokes. Methodology. The material chosen for the research was of a flat die-cutting press, namely its pressure plate drive mechanism.

The article describes the development of rapid-hardening, high-strength fiber-reinforced concrete with increased impact resistance for protective structures. Fiber-reinforced concretes with the addition of Portland cement CEM II/A-LL 42.5 R (C = 390 kg/m3) with polymer structural fiber PMS 1/60 with the addition of PCE were studied. The addition of PMS 1/60 fiber to concrete increases impact strength by 2.8-3.7 times and achieves a strength class of C 40/50. Fiber-reinforced concretes with the addition of Portland cement CEM II/A-S 52.5 R were studied.

The article examines the problem of strengthening reinforced concrete floor slabs with insufficient load-bearing capacity during reconstruction or increased loads. A method is proposed involving partial integration of additional monolithic reinforced concrete beams through pre-formed openings in the slab. Various approaches are analyzed to ensure composite action between the slab and beams. The study aims to theoretically and experimentally determine slab deflection and develop optimal implementation methods.

The paper substantiates the selection of a polymer and filler based on aromatic polyamide to create a material of friction pairs that operate in heavy-duty friction and sealing units of up-to-date vehicles and machinery. The effect of load and sliding speed on the tribological behavior of the initial aromatic polyamide and filled 15%-aramid fiber was studied. As a result of tribological studies, the terminal operating conditions of products made of initial aromatic polyamide and a composite based thereon, filled with aramid fiber, have been determined.

A study on the influence of polycarboxylate-type superplasticizers on the physical and technical properties of fine-grained concrete was conducted. The proposed concept involves creating high-quality, high-strength concretes based on modified cementing systems characterized by improved construction and technical properties.

The production of shredding shafts for industrial shredders presents significant challenges due to the high mechanical loads and exposure to abrasive materials these components must endure. Traditional designs involve the complex and labour-intensive process of welding sprockets to the main shaft, which increases manufacturing, labour, and maintenance costs. This study explores a novel approach to manufacturing shredding shafts by implementing cast sprockets, significantly reducing the complexity and expense associated with traditional designs.