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  1. AU="Strzałkowski, Jarosław"
  2. AU=Yousefifard Mahmoud

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  1. Article: Mechanical Strength and Thermal Properties of Cement Concrete Containing Waste Materials as Substitutes for Fine Aggregate.

    Łukowski, Paweł / Horszczaruk, Elżbieta / Seul, Cyprian / Strzałkowski, Jarosław

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 24

    Abstract: The increasing volume of waste and the requirements of sustainable development are the reasons for the research on new waste management concepts. The research results presented in this paper show the effect of recycled aggregate on the selected ... ...

    Abstract The increasing volume of waste and the requirements of sustainable development are the reasons for the research on new waste management concepts. The research results presented in this paper show the effect of recycled aggregate on the selected properties of cement concrete. The aggregates obtained from three types of wastes are tested: recycled concrete paving, crushed ceramic bricks, and burnt sewage sludges. The recycled aggregates replaced 25% and 50% of the volume of the fine aggregate. The tested aggregates worsen the concrete mixes' consistency and decrease, to some extent, the compressive strength of the concrete. However, the tensile splitting strength of the concrete with recycled aggregates is similar to that of the reference concrete. Using recycled aggregates worsens the tightness of the concrete, which manifests itself by increasing water penetration depth. The thermal properties of concrete are slightly affected by the type and content of the recycled aggregate. Considering the expected improvement in recycled aggregate processing, they can be an alternative to natural aggregates. Using recycled aggregates in cement concrete requires extensive studies to search for ways to increase their possible content without worsening concrete performance.
    Language English
    Publishing date 2022-12-10
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15248832
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: The Effect of Aggregate Shape on the Properties of Concretes with Silica Fume.

    Strzałkowski, Jarosław / Garbalińska, Halina

    Materials (Basel, Switzerland)

    2020  Volume 13, Issue 12

    Abstract: The paper examines the impact of aggregate shape on the compressive strength and thermal properties of concretes with silica fume based on two different aggregates: natural round gravel aggregate and crushed basalt aggregate. Compressive strength and ... ...

    Abstract The paper examines the impact of aggregate shape on the compressive strength and thermal properties of concretes with silica fume based on two different aggregates: natural round gravel aggregate and crushed basalt aggregate. Compressive strength and thermal properties of individual concretes were determined during the first year of specimens curing. Additionally, porosity tests were conducted using mercury intrusion porosimetry and optical porosimetry. Mercury porosimetry tests showed that the use of silica fume led to a decrease in the content of pores of size smaller than 0.15 µm compared to the reference concretes without the addition of silica fume. However, tests carried out on crushed basalt-based concrete showed the presence of numerous additional pores with diameters ranging from 0.05 to 300 μm. In case of natural round gravel aggregate-based concrete, the addition of silica fume brought about an increase in its compressive strength. In turn, basalt-based concrete exhibited notably lower compressive strength values due to significantly higher porosity within the range of more than 70 μm. In basalt concrete, the obtained λ values are much lower than in concretes with normal gravel aggregate. In addition, the specific porosity structure had its impact on the process of drying of specimens of each group which occurred at a significantly faster rate in the basalt-based concrete. In conclusion, it can be stated that the use of crushed basalt aggregate causes a significant aeration of concrete, even despite the use of silica fume. As a result, the concrete based on crushed aggregate is characterized by a definitely lower compressive strength, but also better thermal insulation properties compared to analogous concrete made on natural round gravel aggregate.
    Language English
    Publishing date 2020-06-19
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma13122780
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: The Thermal Parameters of Mortars Based on Different Cement Type and W/C Ratios.

    Stolarska, Agata / Strzałkowski, Jarosław

    Materials (Basel, Switzerland)

    2020  Volume 13, Issue 19

    Abstract: This study examines the thermal parameters of mortars based on different cement type and water-cement W/C ratios. The presented relationships are important from the point of view of thermal insulation of the entire building component, of which the mortar ...

    Abstract This study examines the thermal parameters of mortars based on different cement type and water-cement W/C ratios. The presented relationships are important from the point of view of thermal insulation of the entire building component, of which the mortar is a part. The thermal properties of the mortar, and in particular its dependence on the degree of moisture, is important information from the point of view of hygrothermal simulations of building components. The moisture effect on the thermal properties was tested using nine mortar types. The study consisted of producing nine types of mortar on the basis of three cements (CEM I 42.5R, CEM II A-S 52.5N, CEM III A 42.5N). For each cement type, three variants of specimens were prepared which differed according to their water/cement ratio (0.50, 0.55 and 0.60). The main research of thermal parameters was carried out using a non-stationary method based on the analysis of changing heat flux readings. The thermal conductivity, volume-specific heat and thermal diffusivity values were analyzed. The tests performed allowed for determination of the density of specimens, water absorbability and thermal parameters in three water saturation states: dry, natural and wet. Additional microstructural tests were performed using mercury intrusion porosimetry. The obtained parameters were used to determine the relationship between the measured properties. An adverse effect of dampness on the thermal insulation of the studied materials was confirmed. In extreme cases, the increase in thermal conductivity due to material high moisture was 93%. The cement used affects the relationship between the total specific surface area and the W/C ratio. As expected, the total porosity of specimens was higher for mortars with higher W/C ratios. A strong correlation has been demonstrated between the total surface area and thermal conductivity. The opposite results were obtained when assessing the relationship between the total specific surface area and water absorbability. In case of specimens CEM II A-S 52.5N, the relation was the proportional, and in specimens CEM III A 42.5N, the relationship was inversely proportional to the W/C ratio.
    Language English
    Publishing date 2020-09-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma13194258
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Moisture Influence on Compressive Strength of Calcium Silicate Masonry Units-Experimental Assessment and Normative Calculations.

    Garbalińska, Halina / Strzałkowski, Jarosław / Stolarska, Agata

    Materials (Basel, Switzerland)

    2020  Volume 13, Issue 17

    Abstract: This paper primarily assesses the scale of adverse changes to the compressive strength of different types of silicates due to the influence of moisture. The study covers three groups of silicate units of different strength classes-15, 20 and 25-obtained ... ...

    Abstract This paper primarily assesses the scale of adverse changes to the compressive strength of different types of silicates due to the influence of moisture. The study covers three groups of silicate units of different strength classes-15, 20 and 25-obtained from three different manufacturers. It was demonstrated that in all studied groups, moisture significantly decreased the compressive strength by about 30-40%. In addition, microstructural studies were conducted to analyze the relationship between the specific porosity structure of each group of silicate bricks and their compressive strength. On the basis of SEM (Scanning Electron Microscopy) and EDS (Electron Dispersive Spectroscopy) analysis, the elemental composition of individual silicates was determined and the contact zone between the aggregate and the binder was determined, which largely influenced the obtained compressive strength of each silicates. Next, the study referred to the utility of the normative procedure used to determine the strength class of samples with different geometries and at different moisture concentrations. The results of the calculations showed the high accuracy of the normative-based assessment of strength class, regardless of the manufacturer and the moisture values during examination.
    Language English
    Publishing date 2020-08-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma13173817
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: The feasibility and economic efficiency of selective modernization solutions in a singlefamily house located in Siemianice near Słupsk

    Stolarska Agata / Strzałkowski Jarosław / Szczeciński Michał

    E3S Web of Conferences, Vol 49, p

    2018  Volume 00108

    Abstract: This study presents the results of the analysis on the energy balance of a single-family residential home built in 1986. The authors assess the proposed construction improvements in terms of their ability to enhance the building's energy efficiency and ... ...

    Abstract This study presents the results of the analysis on the energy balance of a single-family residential home built in 1986. The authors assess the proposed construction improvements in terms of their ability to enhance the building's energy efficiency and comfort. The studies were carried out for the needs of the owners who saw the necessity of reducing the maintenance and heating costs of the house and of improving their living conditions. The on-site studies and analyses of the building concerning the calculations for the proposed variants of solutions have pointed to the necessity and relevance of a thermal modernization of the building. The analyses took into consideration the growing requirements of thermal insulation of walls, the EP factor and the growing use of energy from renewable sources. The proposed modernization steps and energy audit calculations helped to select the most efficient solution.
    Keywords Environmental sciences ; GE1-350
    Subject code 690
    Language English
    Publishing date 2018-01-01T00:00:00Z
    Publisher EDP Sciences
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Evaluation of dampness-induced strength reduction of calcium silicate blocks

    Garbalińska Halina / Głowacka Anna / Strzałkowski Jarosław

    E3S Web of Conferences, Vol 49, p

    2018  Volume 00028

    Abstract: Due to its numerous technical advantages as well as health benefits, sand-lime brick is increasingly used in the construction of brick walls, especially in residential buildings. Unfortunately, the occurrence of damp leads to a sharp deterioration of the ...

    Abstract Due to its numerous technical advantages as well as health benefits, sand-lime brick is increasingly used in the construction of brick walls, especially in residential buildings. Unfortunately, the occurrence of damp leads to a sharp deterioration of the technical properties of the material and the environmental conditions inside the building. Given the importance of this issue, an attempt was made to diagnose the extent of dampness variability of the main hygrothermal and strength characteristics of calcium silicate products. The study involved the basic material properties (density in dry and water-saturated conditions), moisture-related properties (capillary adsorption coefficient and sorptivity), thermal coefficients (thermal conductivity and volumetric heat capacity) as well as mechanical properties (compressive strength). This article describes diagnostic studies that were conducted to assess the extent of the effect of dampness on the strength of sand-lime products. In order to render the diagnosis more comprehensive and to include a wider range of silicate blocks available on the market, it was decided to examine three groups of silicate blocks (strength class 15, 20 and 25) obtained from three different factories. It was demonstrated that for all the examined groups dampness caused a significant decrease in compressive strength ranging from about 30% to about 40%.
    Keywords Environmental sciences ; GE1-350
    Subject code 690
    Language English
    Publishing date 2018-01-01T00:00:00Z
    Publisher EDP Sciences
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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  7. Article: Functional Bi

    Cendrowski, Krzysztof / Federowicz, Karol / Techman, Mateusz / Chougan, Mehdi / El-Khayatt, Ahmed M / Saudi, H A / Kędzierski, Tomasz / Mijowska, Ewa / Strzałkowski, Jarosław / Sibera, Daniel / Abd Elrahman, Mohamed / Sikora, Pawel

    Nanomaterials (Basel, Switzerland)

    2024  Volume 14, Issue 2

    Abstract: This study presents a new approach towards the production of sol-gel silica-coated ... ...

    Abstract This study presents a new approach towards the production of sol-gel silica-coated Bi
    Language English
    Publishing date 2024-01-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662255-5
    ISSN 2079-4991
    ISSN 2079-4991
    DOI 10.3390/nano14020168
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Effect of Nano-SiO

    Brzozowski, Piotr / Strzałkowski, Jarosław / Rychtowski, Piotr / Wróbel, Rafał / Tryba, Beata / Horszczaruk, Elżbieta

    Materials (Basel, Switzerland)

    2021  Volume 15, Issue 1

    Abstract: The aim of the research was to determine how the admixture of nanosilica affects the structure and mechanical performance of cement concrete exposed to high temperatures (200, 400, 600, and 800 °C). The structural tests were carried out on the cement ... ...

    Abstract The aim of the research was to determine how the admixture of nanosilica affects the structure and mechanical performance of cement concrete exposed to high temperatures (200, 400, 600, and 800 °C). The structural tests were carried out on the cement paste and concrete using the methods of thermogravimetric analysis, mercury porosimetry, and scanning electron microscopy. The results show that despite the growth of the cement matrix's total porosity with an increasing amount of nanosilica, the resistance to high temperature improves. Such behavior is the result of not only the thermal characteristics of nanosilica itself but also of the porosity structure in the cement matrix and using the effective method of dispersing the nanostructures in concrete. The nanosilica densifies the structure of the concrete, limiting the number of the pores with diameters from 0.3 to 300 μm, which leads to limitation of the microcracks, particularly in the coarse aggregate-cement matrix contact zone. This phenomenon, in turn, diminishes the cracking of the specimens containing nanosilica at high temperatures and improves the mechanical strength.
    Language English
    Publishing date 2021-12-27
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15010166
    Database MEDical Literature Analysis and Retrieval System OnLINE

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