The development and research of modified ultra-high strenght fiber-reinforced multifunctional concrete
Students Name: Chapliak Denys Romanovych
Qualification Level: magister
Speciality: Building Constructions, Products and Materials Technologies
Institute: Institute of Civil Engineering and Building Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: англійська
Abstract: Chaplyak D. R., Sanytskyi M. A. (head). "Development and research of modified high-strength multi-purpose fiber concrete". Master’s qualification thesis. - Lviv Polytechnic National University, Lviv, 2022. Extended abstract. The master’s thesis is devoted to the development of ultra-high-strength fiber concrete based on Portland cement PC II/А-В-500Р-Н PrJSC "Ivano-Frankivskcement" by designing the composition using polyfraction aggregates, microfillers, basalt fiber and superplasticizer of the polycarboxylate type. An important problem is the provision of construction with ultra-high-strength concrete with a strength of more than 120 MPa. Such materials are characterized by unique properties (high plasticity, low permeability, very high compressive strength, increased viscosity) and belong to the class of ultra-high-performance concretes. At the same time, the combination of such concrete with fiber is of great importance. Such concretes are especially necessary for special purpose structures (tunnels, bridge structures, etc.). Usually, the production of ultra-high-strength concrete is associated with the need to use high-quality fine aggregates, which are characterized by high grain strength and ensure minimal water consumption and voids. One of the most important factors for obtaining high-strength concrete capable of providing both mechanical properties and structural durability is a low (within 0.20-0.25) water-cement ratio (W/C). In this case, hyperplasticizers of the polycarboxylate type, which are characterized by a water-reducing effect of 35-40%, can be particularly effective. When providing low W/C values, the creation of a dense microstructure is ensured due to the complex use of additives of highly dispersed microfillers, which allows to obtain modified ultra-high-strength dispersed-reinforced concretes of multifunctional purpose. The object of the research is modified high-strength multi-purpose fiber concrete The subject of the study is the processes of regulating the properties of ultra-high-strength dispersed-reinforced concrete based on Portland cement PC II/А-В-500Р-Н PrJSC "Ivano-Frankivskcement", microfillers, polyfractional fine aggregates using hyperplasticizers of the polycarboxylate type. The purpose of the research is to study the influence of microsilica additives, superzeolite, polycarboxylate-type modifiers and basalt fiber on the processes of structure formation of the cementing matrix and the physical and mechanical properties of fine-grained ultra-high-strength dispersed reinforced concrete using polyfraction aggregates, optimization of their compositions. Research results: A review of literature sources on the use of modified ultra-high-strength dispersed-reinforced concretes on polyfraction aggregates was carried out. The characteristic properties of ultra-high-strength concrete are considered and the relevance of using such composite materials in construction is determined. The grain composition of fine aggregate of different sizes was selected for the formation of the densest cementing matrix of modified ultra-high-strength concretes. Compositions of modified ultra-high-strength fine-grained concrete based on Portland cement of Ivano-Frankivskcement PJSC with the addition of microfiller and polycarboxylate superplasticizer were designed and studied by the method of mathematical planning of the experiment. Based on these model-diagrams, it was concluded that the most optimally effective composition is at the consumption of 150 wt.% of superzeolite and hyperplasticizer. It has been shown that modified concrete mixtures with high early strength are effective when used in construction production in combination with additives of superzeolite and superplasticizer of polycarboxylate type Master Glenium ACE 430. Key words: modified ultrahigh-strength concrete, basalt fiber, polyfraction fine aggregate, superzeolite, strength. List of used literary sources. 1. L. Y. Dworkin, E. M. Babich, V. V. Zhitkovsky, and others. High-strength fast-hardening concretes and fiber concretes. Rivne: NUVHP. 2017. 331 p. 2. Sanytskyi M.A., Kropyvnytska T.P., Hevyuk I.M. Quick-hardening clinker-effective cements and concretes. Monograph. Lviv: Prostir-M Publishing House, 2021. 215 p 3. Hots V. I., Pavlyuk V. V., Shilyuk P. S. Concretes and construction mortars: a textbook. K.: Osnova, 2016. 568 p. 4.Perry V.H. What Really is Ultra–High Performance Concrete? – Towards a Global Definition. The 2nd Int. 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