Study on the Effects of Ultrasonic Agitation on CO2 Adsorption Efficiency Improvement of Cement Paste

To realize high-efficiency CO2 absorption by fresh cement paste, ultrasonic vibration technology is introduced into the CO2 absorption test device used in this study. Influences of ultrasonic frequency on the CO2 absorption rate (CO2 AR) and the ultimate absorption amount of fresh cement paste are analyzed. Furthermore, the influencing laws of the CO2 absorption amount (CO2 AA) on the fluidity, pore distribution, and mechanical properties of cement paste under ultrasonic vibrating agitation are analyzed by measuring the variations of the CO2 AA of cement paste. Results demonstrate that ultrasonic vibrating agitation not only can increase the CO2 AR and ultimate absorption amount of fresh cement paste, but also can optimize the internal pore structure of materials and compressive strength of cement-based materials.

Self-Сompacting Сoncretes, which hardening at different temperature conditions

In the article the features of reinforced concrete hardening at different temperature conditions and the current issues of preparation technology of Self-Сompacting Сoncretes (SCC) on the basis of superplasticized cementitious systems, combining knowledge of structure and modifying Portland cement compositions "Portland cement – active mineral additives – microfiller – superplasticizer – accelerator of hardening" to search for rational making provision of technical and building properties of concrete in the changing factors of its composition, technology and exploitation are shown. The physico-chemical peculіarities of hydration and hardening processes of superplasticized cementitious systems were established. The problem of obtaining Self-Compacting mixtures and Rapid-Hardening Concretes on their basis by the direct structure formation of cementitious matrix was solves. The optimization of Self-Compacting Concretes composition on the base of superplasticized cementitious systems with high early strength was carried out. The quality parameters of developed concretes were investigated and the effectiveness of their using in different temperature conditions was shown. The results of the studies found that the use of the superplasticized cementitious systems allows to influence on technological properties and kinetics of structure formation and create concrete structure with improved construction and technical properties at a different temperature conditions. Technological solutions designing of superplasticized cementitious systems that solves the problem of obtaining the Self-Сompacting Сoncretes (SCC) on their basis with using non-vibration technology are established. This creates an opportunity allows to solve the problem of obtaining for enabling early loading, reducing the production cycle, increasing turnover and formwork acceleration of monolithic buildings and structures at different temperature conditions.

Construction of the basement of cottages in water-saturated soils using vibration technology

he paper discusses the directions of technology development using a vibration method that allows arranging basements in low-rise buildings with external waterproofing. A new technology is offered allowing arranging external waterproofing using special cement-based waterproofing compounds. To optimize the timing of construction process, the authors propose developing the ground excavation with a vibrating grab. Technological operations and design solutions for the sequence of works have been developed.

INFLUENCE OF STRENGTHENING OF PARTS ON THE RELIABILITY OF MACHINES

The paper considers the issues of increasing the reliability of agricultural machinery through the use of reinforcing processing of recovered machine parts by plastic deformation, which provides an increase in the quality of their surface layer during recovery. The operational stability of the piston fingers and the upper heads of the connecting rods restored by vibration reinforcement on the engines working in the mechanized agricultural complex was carried out: tractor - agricultural machine - car. Studies have shown that the amount of wear of piston fingers restored by the vibration deformation method is 1.23 times smaller than the traditional method of recovery, which confirms the effectiveness of vibration technology. Technological processes of restoration of discs of diggers of beet harvesters, discs of coulters of grain planers, plow blades with use of vibrating vibrations of the processing tool are developed and put into production. The results of these developments showed an increase of 1.21 times the time of beet harvester harvesting with the diggers' wheels with the vibration-strengthened method; an increase in technical use factor of 1.07 times, compared to new 65G steel wheels. To improve the reliability of the PLN-5-35, PLN-3-35 plows, the technology of restoration of working bodies - blades is developed and introduced into production, which provides for increase of their durability and durability. The coefficient of technical use of the plow units with the blades restored by the developed technology is 1.01 times higher than that of the plow units with the new blades made of 65G steel. The wear rate of the toe, width and thickness of the blade are 1.51 respectively; 1.22 and 1.27 times less than the new 65G steel blades. The results of the study of vibrating reinforcing processing of working bodies of agricultural machinery help to increase their resource, which provides increased reliability of machines.