The relevance of this study is conditioned by the high degree of importance of creating the latest modifications of the polymer–bitumen binder for the manufacture of high-quality asphalt concrete, for its subsequent use in the construction of motorways and concrete pavements of airfields. In this context, the purpose of the study is to obtain new, scientifically substantiated technological solutions for the development and practical application of effective nanomodified polymer-bitumen binders (PBBs) that can improve the operational characteristics and duration of practical use of asphalt. The study results clearly demonstrate the fact that carbon nanotubes (CNTs) are a stabiliser and an ageing inhibitor of polymer–bitumen binders (PBBs), while contributing to a decrease in the intensity of its operational destruction over time by more than 10 times relative to the compositions of PBB with structuring additives, which is essential in the preparation and practical use of asphalt concrete for the construction of motorways and airfields. The results obtained are of significant importance for developers of modern technologies for manufacturing asphalt concrete for road construction, and road maintenance workers who professionally solve the problems of road maintenance, applying the latest practical developments in the field of road construction and repair in their activities.
The recycling methods used in the construction and repairing of asphalt concrete pavements are being constantly improved, and the improvements mostly fall under one of the following common avenues of innovation: developing new binders based on bitumen and cement; developing new varieties of asphalt concrete and other materials having an equivalent utility and function; and developing additives that can be used in the production of new types of binders that can enhance the performance properties of the pavements. This article aims to develop the composition and determine the physical-mechanical and structural-rheological properties of asphalt concrete reclaimed by the hot recycling method and reinforced by fiber of fly ash from thermal power plants (TPP). The author of this article developed a mechanism for the interaction between fiber and bitumen in asphalt binder and acquired an optimum composition of hot granular asphalt concrete. During the research, the author evaluated the utility of fiber used as an additive in reclaimed asphalt concrete, studied its effect on the properties of hot reclaimed asphalt concrete, and examined the technological and performance properties and durability of the material obtained. The fiber of fly ash used in the hot recycling method made it possible to reduce the cost and ensure the high quality and durability of the structural layer of road pavement. Our experiments with analyses of the obtained composition indicated that employing it in the construction of the structural layer of road payment would result in superior structural integrity. Hot recycling made it possible to obtain thick bound layers characterized by the homogeneity of the material. For the first time, the author studied the effect of using fiber of fly ash from Chinese TPP in hot reclaimed asphalt concrete, and the results have proved the rationality of using this composition.
18 September 2023 in International Journal of Concrete Structures and Materials
The use of complex modifiers for plain cement concrete mixtures and concrete is becoming increasingly popular in modern materials science. The article presents studies of the influence of a polymer additive structured by carbon nanomaterials on physical and mechanical characteristics of plain cement concrete mixtures. IR spectroscopy and thermogravimetry have shown that the use of carbon nanomaterials significantly altered the structure of plain cement concrete mixtures. As a result of the fact that the high-strength nanomaterial is the center of crystallization of cement rock newly formed structures, a denser reinforced microstructure is formed, which significantly increases the strength properties of plain cement concrete mixtures. The inclusion of a polymer complex additive in plain cement concrete mixtures leads to higher and longer plasticizing, which plays an important role in the production of monolithic products. It was determined that, in the presence of a complex modifier (polymer additive structured by carbon nanotubes), the crystalline structure of calcium hydrosilicates is compacted, which causes high physical and mechanical characteristics of modified plain cement concrete mixtures. It has been experimentally shown that the additive Ethacryl HF (France) from the class of polycarboxylates, chosen for research, acts as an accelerator for setting and curing cement paste, and also increases its strength characteristics. In general, in this study, there is a water-reducing effect from the application of the additive for all plain cement concrete mixtures. Water requirements are reduced by 5 mas. %, while the strength is increased by 19%. The formulation of plain cement concrete mixtures modified by polymer additives, structured by carbon nanotubes, with high performance were developed.
1 January 2022 in Science and Engineering of Composite Materials
Modern materials science has faced the problem of reducing the cost of raw materials and labor costs while obtaining basic construction materials (cement concrete) with increased performance properties. The article aims to substantiate the use of carbon nanotubes of fly ash as a cement concrete modifier to be reasonable for solving the above problem. Experimental studies are carried out using standard and special methods. The technological properties of cement concrete mixtures are determined in accordance with the European and American standards. The study investigates the impact of carbon nanotubes of fly ash on the structure and properties of the mineral Portland cement binder. The article provides the examination of structural and rheological characteristics of nano-modified cement concrete mixtures. The effect of a carbon nano-modifier on the strength, deformation, and performance properties of cement concrete mixtures is defined. As a result, the optimal composition of nano-modified cement concrete mixture has been developed that meets the criteria of concrete compressive strength and flowability. Positive research results allow determining the areas of application of the obtained compositions in civil engineering.
11 August 2022 in European Journal of Environmental and Civil Engineering
Slowly curingepoxy asphalt concrete has high physical properties and low sensitivity to temperature changes, which allows ituse as a road surface on a rigid base. However, a negative property of epoxy asphalt concrete is the ability to gain strength over a long period of operation. The epoxy-asphalt concrete really gains its initial strength in a relatively short time, but the feature of classic epoxy asphalt concrete is their subsequent set of strength, which in winter at negative temperatures can lead to the destruction of the matrix during movement and negatively affect the performance of both the road and the cars. To solve this problem, optimum types of modifying additives for changing bitumen properties and their possible use in epoxy asphalt concrete were considered. Changes in the structure of bitumen with fibre were investigated by the IR spectroscopy method; the dependence of bitumen penetration on temperature, as well as the mide and the amount of additives, influencing the bitumen plasticity were studied. Adhesive characteristics of bitumen at different temperatures were also determined. A directed change in the properties of bitumen in asphalt concrete is the most effective way to increase the performance and durability of road surfaces.