Andrzej Ubysz

• Professor
• Wrocław University of Science and Technology

Na podstawie badań doświadczalnych wykonanychna belkach w skali półnaturalnej z betonu o wysokiej wytrzymałościpokazano, jak stopień zbrojenia i średnica stalowychprętów zbrojeniowych wpływają na wartości rezydualnych ugięćbelek przy jej cyklicznych obciążeniach. Badania przeprowadzonona 4 seriach belek, w których na poszczególnych poziomachobciąże...

The utilization of powder generated during the recycling process of concrete waste is considered crucial for achieving the complete recycling of concrete waste. This study investigated the effect of thermal activation on using recycled concrete powder (RCP), produced from repeated recycling of concrete, as a supplementary cementitious material. RCP...

When processing construction and demolition waste, determining the most effective waste management, potential use and recycling method for the identified materials is a key element. To do this, it is necessary not only to determine the type of materials, but also knowledge which aspects of the quality of the original materials are relevant for recy...

This research is part of the project "Seeking true sustainability by multiple recycling of thermal-activated waste concrete powder as a partial cement replacement," funded by the National Science Centre of Poland (Grant No. 2022/45/N/ST8/01782).

The study investigated the effects of construction waste powders exposed to elevated temperatures on the properties of cement mortar. The waste powders were obtained from demolished granite and clay blocks after more than 15 years of their service life. The exposure temperatures were 200 °C, 400 °C, 600 °C, and 800 °C. The heat-treated and untreate...

This article investigates the degradation of stiffness in high and standard-strength concrete due to the influence of repeated loading and considers the non-linear behavior arising from localized or natural defects of concrete. The article also refers to the models from existing literature that evaluate the characteristics of concrete by enhancing...

The decrease in the quality of recycled aggregate due to an increase in the number of recycling is a primary factor that limits the multi-recycling of concrete. This degradation adversely affects concrete performance; thus, the characteristics of recycled aggregate should be considered during the mix design stage, but little research has taken that...

The article discusses the use of one of coatings protecting and strengthening concrete surfaces. It is polyurea coatings to strengthen waterproofing in tanks for water and other related liquids. Details of polyurea application technologies for specific tank structures and preparatory works that must be performed before the application of spray poly...

For complete utilization of construction and demolition (C&D) waste, an investigation of all size fractions of C&D waste generated during the recycling process should be conducted. In this work, the effects of three recycled concrete materials with different sizes (recycled coarse aggregate (RCA) with a size of 4.75–25 mm, recycled fine aggregate (...

Research on recycled concrete aggregates (RCAs) has been progressively advanced. Beyond replacing natural aggregates with RCA, discussions have been held on the effect of the parent concrete and repeatedly recycled aggregate concrete. Although it has been reported that RCA can be technically used for structural concrete, due to several other factor...

In the mechanics of concrete constructions, one distinguishes between residual and elastic strains. Cyclic loadings evoke changes mainly in the elastic strains; however, the total strains are decided by the sum of the residual and elastic strains. The knowledge of the ratio between the residual and total strains allows to predict the total deformat...

This article presents the issues related to using by-products and waste materials in constructionand mining industry. The current applications of selected materials in various areas are presented, with particularfocus on cases in the construction and mining industries, where waste-based composites sealed with various hydraulic binders are used to b...

The analysis of the applied development systems in the extraction of minerals is carried out. The main problems arising during the development of mineral deposits are formulated. A method is proposed that allows solving the problem of choosing a technology for developing a mineral deposit and selecting a rational composition of a filling mixture fo...

The constructive basis of a multi-story building is the spatial bearing system of buildings. In accordance with the chosen mathematical apparatus of the study, the spatial load-bearing system of a multi-storey building is a discrete vertical reinforced concrete structure formed by shear walls, and united by constant height connections with certain...

The article describes a modern approach to the technology of backfilling of working space, taking into account the sustainable development of mining. The aspects of economic efficiency, safety and ecology are considered. A detailed analysis of various backfilling methods that are used in modern enterprises is given. The advantages and disadvantages...

The analysis of the applied development systems in the extraction of minerals is carried out. The main problems arising during the development of mineral deposits are formulated. A method is proposed that allows solving the problem of choosing a technology for developing a mineral deposit and selecting a rational composition of a filling mixture fo...

Modern approach to Structural Health Monitoring of building structures demands for reliable data concerning current technical condition of analysed structure or its parts. Data are provided preferably by means of non-destructive testing or visual inspections. When the analysed object is non- or hardly accessible (like in the case of tall industrial...

Industrial concrete floors made directly on the ground are concrete slabs reinforced with structural reinforcement and often additionally reinforced with dispersed reinforcement in the form of polypropylene or steel fibers. More often than not, these floors are not separated from the reinforced concrete slab; they form a monolithic whole with it. D...

The article presents a proposal to use basalt fibers recovered from damaged basalt rods. The introductory part reveals state of the art review on application of various fibers to improve mechanical properties of concrete composites. Authors refer to applications of steel, polypropylene, glass and carbon fibers, their advantages and limitations. Bas...

The influence of an aggressive environment affects the appearance of physico-mechanical and physico-chemical corrosion processes, which in turn affects the depreciation of concrete properties, the redistribution of internal forces in sections and the depreciation of the working conditions of the reinforcement. The article discusses issues related t...

This paper presents a methodology based on the finite element method to simulate the flow of granular materials. Moreover, it allows proper estimation of dynamic pressure during silo discharge since this subject is still under discussion, especially for designing silos with an insert (an input element). A 2-D simulation of the discharge process of...

The article presents a proposal to use basalt fibers recovered from damaged basalt rods. The introductory part reveals state of the art review on application of various fibers to improve mechanical properties of concrete composites. Authors refer to applications of steel, polypropylene, glass and carbon fibers, their advantages and limitations. Bas...

Industrial concrete floors made directly on the ground are concrete slabs reinforced with structural reinforcement and often additionally reinforced with dispersed reinforcement in the form of polypropylene or steel fibers. More often than not, these floors are not separated from the reinforced concrete slab; they form a monolithic whole with it. D...

This work is devoted to the methodology for calculating the compressed reinforced concrete elements under dynamic loading, which takes into account the lack of adhesion of tensile reinforcement to concrete. As experiments have shown, the lack of adhesion between concrete and reinforcement leads not only to a decrease in the bearing capacity, but al...

Non-destructive tests of reinforced concrete chimneysare an important element in assessing their condition, making it possible to forecast their safe life. Industrial chimneys are exposed to the strong action of acidic substances e.g. of the condensation of the flue gases. Condensate affects to the inside of the thermal insulation and penetrating t...

The paper presents a statistical description of the values of random variables of pressure and temperature as the most important loads on wall of silo, in which hot materials, such as cement, clinker, fly ash, and raw meal are stored. An attempt to statistically describe the pressure and temperature and their additive share in loads are clearly pre...

A review of the current state of the issue of describing the deformation of columns confined by CFRP jackets under of dynamic loading is carried out. The insufficiency of the study of elements under the influence of axial dynamic load is indicated. The dynamic increase factors (DIF) for concrete and CFRP, which are obtained by the results of existi...

Durability becomes a very important factor in design. Concrete, and in particular reinforced concrete constructions, are sensitive to environmental impacts (actions on construction) and also have a strong environmental impact (e.g. pollution, noise, dynamic interactions etc.). The feature of concrete, which is durability, has an impact on the relia...

Cracked walls of chimneys have a serious impact on their durability. There are many reasons for chimney cracks. Among them, the most important is the impact of the environment in which the chimneys operate, the method of concrete care, the amount of reinforcement in the walls of the chimneys, the quality of concrete and the first start-up of the ch...

This paper presents an experimental investigation of the discharge flow pressure in the vertical silo and the hopper due to the use of insert (top cone with trunk cone bottom). Using the Insert inside the silos is one of the proposed solutions to avoid the problems of having funnel flow pattern, which has a significant effect on the distribution of...

Non-destructive tests of reinforced concrete chimneys, especially high ones, are an important element in assessing their condition, making it possible to forecast their safe life. Industrial chimneys are often exposed to the strong action of acidic substances, They are negatively exposed to the condensation of the flue gases. Condensate affects the...

The nondestructive testing of reinforced concrete chimneys, especially the high ones, is an important element of the assessment of their condition, making it possible to forecast their safe service lifespan. Industrial chimneys are often exposed to the strong action of acidic substances – they are adversely affected by the flue gas condensate on th...

Impact of geotechnical works related to plunging piles in the ground and modification of the condition of the soil foundation for concrete in the early stage of its bonding, and influence on adhesion of reinforcing steel to concrete can determinate the target capacity of a reinforced concrete structure. Impact of vibrations testing on bond strength...

Multilevel underground garages are often an ambitious geotechnical task in urban agglomeration. Lower levels of foundation slabs are often located below the groundwater level, which requires effective protection of the structure against groundwater invasion. The constructor’s task is to design slabs and walls so that no cracks will form to allow gr...

Multilevel underground garages are often an ambitious geotechnical task in urban agglomeration. Lower levels of foundation slabs are often located below the groundwater level, which requires effective protection of the structure against groundwater invasion. The constructor’s task is to design slabs and walls so that no cracks will form to allow gr...

This paper deals with the failure of one of the sports and entertainment halls in Poland. The facility was built in the years 1977-85. Its main load-bearing members were three-hinged double-sloped frames with a total span of 45 m. The main girders of the frames were made of glued-laminated timber. The girders rest on reinforced concrete pillars. Be...

There are presented in this paper some problems connected with reinforced concrete shell objects operation in the aggressive environment and built in method of formworks. Reinforced concrete chimneys, cooling towers, silos and other shells were built for decades. Durability of cracked shells are one of the most important parameters during process o...

In view of location and tight work schedule of civil projects, more and more frequently the various kinds of work overlap each other in space and time. Hence, their interactions need to be anticipated. An example of such works are pile driving which generate vibrations, which begs a question whether and to what extent they affect proper operation o...

Composite materials have been gaining increasing popularity in many industries, such as: the automotive industry, aviation, electrotechnics and construction. Due to the widespread use of composites the problem of their utilization and reuse arises. This paper presents an attempt to utilize basalt discards as fibre reinforcement for concretes.

The products covered by the common name polyurea were first developed and marketed in the United States in the 1980’s In the first period polyurea was used as a protective coating of polyurethane foam used for thermal insulation of roofs, and in the 1990s many other uses were quickly disseminated. In Europe this technology appeared in the second ha...

PL W artykule przedstawiono wyniki prowadzonych na świecie badań nad nanorurkami węglowymi, a ściślej nad ich potencjalnym zastosowaniem jako nanododatku do zapraw naprawczych w konstrukcjach żelbetowych. W badaniach wstępnych określono najlepszy stosunek masowy włókien do cementu pod względem wytrzymałości na ściskanie i rozciąganie przy zginaniu....

The paper presents risks of the use of building materials with radioactive properties. The element that generates almost half of the natural radiation is radon. The most common medical complications are radiation sickness and cancer, affecting the lungs. The workplaces where building materials are manufactured with the use of radioactive materials...

The paper presents method of calculation of eigenfrequencies of the cracked reinforced concrete beams including discreet model of crack. The described method is based on the stiff finite elements method. It was modified in such a way as to take into account local discontinuities – cracks. In addition, some theoretical studies as well as experimenta...

The paper presents method of calculation of natural frequencies of the cracked reinforced concrete beams including discreet model of crack. The described method is based on the stiff finite elements method. It was modified in such a way as to take into account local discontinuities (ie. cracks). In addition, some theoretical studies as well as expe...

The paper presents practical application of Borcz's [1] method which develops original concepts concerning concrete model and reinforced concrete structure in the first and second stage of work to determine generalised displacements and internal forces in a cracked reinforced cross-section. The significant assumption of elastic structure work with...

The monograph is a continuation of the research of Prof. Augustyn Borcz. It presents an original proposal of concrete model and the theory of reinforced concrete construction in the first and the second phase of work. The essence of the problem is the assumption about the elastic work of construction at reproducible load and treatment of strains in...

The paper presents practical application of Borcz's method, which develops original concepts concerning the model of concrete and reinforced concrete structure in the first and second stage of work to determine generalized displacements and internal forces in a cracked reinforced cross-section. The significant assumption was made of the elastic beh...

The effect of redistribution of internal forces is so far not applied sufficiently. It is a result of passive approach to such design in obligatory standards. The presented research was realized within a discussion about the standard of design of the reinforced concrete constructions. The effect of type of steel on redistribution of internal forces...

The paper is a proposal of calculation of internal forces and dislocations in the reinforced concrete beams before and after cracking. For the ideally elastic bars transfer matrix proposed by Rakowski (3) was applied. The effects associated with cracking were introduced by means of the Borcz's theory (1, 2) in the spectrally way. In part fourth of...

The paper contains a description of dynamic effects in the silo wall during the outflow of a stored material. The work allows for determining the danger of construction damage due to resonant vibrations and is of practical importance by determining the influence of cyclic pressures and vibro -creeping during prolonged use of a silo. The paper was d...