Yazar "Dobiszewska, Magdalena" seçeneğine göre listele

Listeleniyor 1 - 10 / 10
  • [ X ]
    Öğe
    Fresh Properties and Fracture Energy of Basalt and Glass Fiber-Reinforced Self-Compacting Concrete
    (Asce-Amer Soc Civil Engineers, 2022) Gultekin, Adil; Beycioglu, Ahmet; Arslan, Mehmet Emin; Serdar, Ahmet Hamdi; Dobiszewska, Magdalena; Ramyar, Kambiz
    In this study, the fresh properties, fracture energy, compressive strength, and flexural strength of self-compacting concrete including glass or basalt fibers were examined, and the effect of fibers on these properties were studied comparatively. For this purpose, fibers having three different lengths (6, 12, and 24 mm) were used in two different contents (2 and 4 kg/m(3)). The workability of concrete mixtures decreased with fiber addition. The negative effect of basalt fibers on workability was greater than that of the glass fibers. The reduction in flow diameter was up to 40% and 44% as well as the reduction in L-box ratio was up to 41% and 48% in glass and basalt fiber mixtures, respectively. While the fiber addition generally reduced the compressive strength, it increased the flexural strength and fracture energy significantly. Increase in flexural strength was up to 58.6% in glass fiber and 43.5% in basalt fiber mixtures. The fracture energies of glass and basalt fiber mixtures were up to 55.1% and 30.4% higher than that of the control mixture, respectively. (C) 2021 American Society of Civil Engineers.
  • [ X ]
    Öğe
    Influence of Rock Dust Additives as Fine Aggregate Replacement on Properties of Cement Composites-A Review
    (Mdpi, 2022) Dobiszewska, Magdalena; Bagcal, Orlando; Beycioglu, Ahmet; Goulias, Dimitrios; Koksal, Fuat; Niedostatkiewicz, Maciej; Urunveren, Husamettin
    Concrete production consumes enormous amounts of fossil fuels, raw materials, and is energy intensive. Therefore, scientific research is being conducted worldwide regarding the possibility of using by-products in the production of concrete. The objective is not only to identify substitutes for cement clinker, but also to identify materials that can be used as aggregate in mortar and concrete productions. Among the potential alternative materials that can be used in cement composite production is rock dust of different geological origin. However, some adversarial effects may be encountered when using rock dust regarding the properties and durability of mortars and concrete. Therefore, comprehensive research is needed to evaluate the adequacy of rock dust use in cementitious composite production. This paper presents a comprehensive review of the scientific findings from past studies concerning the use of various geological origins of rock dust in the production of mortars and concrete. The influence of rock dust as a replacement of fine aggregates on cementitious composites was analyzed and evaluated. In this assessment and review, fresh concrete and mortar properties, i.e., workability, segregation, and bleeding, mechanical properties, and the durability of hardened concrete and mortar were considered.
  • [ X ]
    Öğe
    Influence of Rock Dust Additives as Fine Aggregate Replacement on Properties of Cement Composites-A Review
    (Mdpi, 2022) Dobiszewska, Magdalena; Bagcal, Orlando; Beycioglu, Ahmet; Goulias, Dimitrios; Koksal, Fuat; Niedostatkiewicz, Maciej; Urunveren, Husamettin
    Concrete production consumes enormous amounts of fossil fuels, raw materials, and is energy intensive. Therefore, scientific research is being conducted worldwide regarding the possibility of using by-products in the production of concrete. The objective is not only to identify substitutes for cement clinker, but also to identify materials that can be used as aggregate in mortar and concrete productions. Among the potential alternative materials that can be used in cement composite production is rock dust of different geological origin. However, some adversarial effects may be encountered when using rock dust regarding the properties and durability of mortars and concrete. Therefore, comprehensive research is needed to evaluate the adequacy of rock dust use in cementitious composite production. This paper presents a comprehensive review of the scientific findings from past studies concerning the use of various geological origins of rock dust in the production of mortars and concrete. The influence of rock dust as a replacement of fine aggregates on cementitious composites was analyzed and evaluated. In this assessment and review, fresh concrete and mortar properties, i.e., workability, segregation, and bleeding, mechanical properties, and the durability of hardened concrete and mortar were considered.
  • [ X ]
    Öğe
    Load-Deflection Behavior of Over- and Under-Reinforced Concrete Beams with Hybrid FRP-Steel Reinforcements
    (Mdpi, 2021) Kartal, Saruhan; Kalkan, Ilker; Beycioglu, Ahmet; Dobiszewska, Magdalena
    The present study pertains to the load-deflection behavior and cracking moments of concrete beams with hybrid FRP-steel reinforcement. Under and over-reinforced hybrid beams were tested for failure along with reference beams with only steel or FRP reinforcement. The first-cracking moments of the beams were estimated analytically by using different uncracked moments of the inertia and modulus of rupture definitions. The uncracked moment of inertia definitions include the gross and uncracked transformed moments. The adopted modulus definitions are comprised of the experimental values from tests on prisms and the analytical values from the equations in different concrete codes. Furthermore, analytical methods were developed for estimating the deflections of concrete beams with hybrid FRP-steel or only FRP reinforcement. Two different types of elastic moduli, namely the secant modulus corresponding to the extreme compression fiber strain and the ACI 318M-19 modulus, were used in deflection calculations. Closer estimates were obtained by using the secant modulus, particularly in hybrid-reinforced beams. In the post-yielding region of the steel tension reinforcement, the deflection estimates were established to lay in closer proximity to the experimental curve when obtained by adding up the deflection increments instead of directly calculating the total deflections from the elastic curve equation. Accurate estimation of the cracking moment was found to be vital for the close prediction of deflections.
  • [ X ]
    Öğe
    Optimization Based on Toughness and Splitting Tensile Strength of Steel-Fiber-Reinforced Concrete Incorporating Silica Fume Using Response Surface Method
    (Mdpi, 2022) Koksal, Fuat; Beycioglu, Ahmet; Dobiszewska, Magdalena
    The greatest weakness of concrete as a construction material is its brittleness and low fracture energy absorption capacity until failure occurs. In order to improve concrete strength and durability, silica fume SF is introduced into the mixture, which at the same time leads to an increase in the brittleness of concrete. To improve the ductility and toughness of concrete, short steel fibers have been incorporated into concrete. Steel fibers and silica fume are jointly preferred for concrete design in order to obtain concrete with high strength and ductility. It is well-known that silica fume content and fiber properties, such as aspect ratio and volume ratio, directly affect the properties of SFRCs. The mixture design of steel-fiber-reinforced concrete (SFRC) with SF addition is a very important issue in terms of economy and performance. In this study, an experimental design was used to study the toughness and splitting tensile strength of SFRC with the response surface method (RSM). The models established by the RSM were used to optimize the design of SFRC in terms of the usage of optimal silica fume content, and optimal steel fiber volume and aspect ratio. Optimum silica fume content and fiber volume ratio values were determined using the D-optimal design method so that the steel fiber volume ratio was at the minimum and the bending toughness and splitting tensile strength were at the maximum. The amount of silica fume used as a cement replacement, aspect ratio, and volume fraction of steel fiber were chosen as independent variables in the experiment. Experimentally obtained mechanical properties of SFRC such as compression, bending, splitting, modulus of elasticity, toughness, and the toughness index were the dependent variables. A good correlation was observed between the dependent and independent variables included in the model. As a result of the optimization, optimum steel fiber volume was determined as 0.70% and silica fume content was determined as 15% for both aspect ratios.
  • [ X ]
    Öğe
    Physical Properties and Microstructure of Concrete with Waste Basalt Powder Addition
    (Mdpi, 2020) Dobiszewska, Magdalena; Beycioglu, Ahmet
    The natural aggregates are one of the main components in the production of concrete. Although deposits of natural aggregates lie on the earth's surface or at low depths and belong to common deposits, the shortage of aggregate, especially natural sand, is presently observed in many countries. In such a situation, one is looking for other materials that can be used as a substitute for natural aggregates in mortars and concrete production. This paper presents the results of an experimental investigation carried out to evaluate the potential usage of waste basalt powder in concrete production. For this purpose, the waste basalt powder, which is a by-product of the production of mineral-asphalt mixtures, was substituted with 10%, 20%, and 30% sand replacement. In the experimental program, the workability, compressive strength, water transport properties, and microstructural performances were evaluated. The results showed that the production of concretes that feature a strong internal structure with decreased water transport behavior is possible with waste basalt usage. Furthermore, when waste basalt powder is used as a partial sand replacement, the compressive strength of concretes can be increased up to 25%. According to the microstructural analyses, the presence of basalt powder in concrete mixes is beneficial for cement hydration products, and basalt powder substituted concretes have lower porosity within the interfacial transition zone.
  • [ X ]
    Öğe
    Physical Properties and Microstructure of Concrete with Waste Basalt Powder Addition
    (Mdpi, 2020) Dobiszewska, Magdalena; Beycioglu, Ahmet
    The natural aggregates are one of the main components in the production of concrete. Although deposits of natural aggregates lie on the earth's surface or at low depths and belong to common deposits, the shortage of aggregate, especially natural sand, is presently observed in many countries. In such a situation, one is looking for other materials that can be used as a substitute for natural aggregates in mortars and concrete production. This paper presents the results of an experimental investigation carried out to evaluate the potential usage of waste basalt powder in concrete production. For this purpose, the waste basalt powder, which is a by-product of the production of mineral-asphalt mixtures, was substituted with 10%, 20%, and 30% sand replacement. In the experimental program, the workability, compressive strength, water transport properties, and microstructural performances were evaluated. The results showed that the production of concretes that feature a strong internal structure with decreased water transport behavior is possible with waste basalt usage. Furthermore, when waste basalt powder is used as a partial sand replacement, the compressive strength of concretes can be increased up to 25%. According to the microstructural analyses, the presence of basalt powder in concrete mixes is beneficial for cement hydration products, and basalt powder substituted concretes have lower porosity within the interfacial transition zone.
  • [ X ]
    Öğe
    Use of GRP Pipe Waste Powder as a Filler Replacement in Hot-Mix Asphalt
    (Mdpi, 2020) Beycioglu, Ahmet; Kaya, Orhan; Yildirim, Zeynel Baran; Bagriacik, Baki; Dobiszewska, Magdalena; Morova, Nihat; Cetin, Suna
    There is an increasing global trend to find sustainable, environmentally friendly and cost-effective materials as an alternative to limited natural raw materials. Similarly, the use of waste materials has been gaining popularity in the production of hot-mix asphalt (HMA). In this study, the sustainable use of glass-fiber-reinforced polyester (GRP) pipe waste powder (GRP-WP), gathered from the cutting and milling process of GRP pipe production, utilizing it in asphalt mixes as a filler, is evaluated based on lab testing to find out: (i) if it produces similar or better performance compared to the most conventionally available filler material (limestone) and, (ii) if so, what would be the optimum GRP-WP filler content to be used in asphalt mixes. For this reason, an experimental test matrix consisting of 45 samples with three different amounts of binder content (4%, 4.5% and 5.0%), and a 5% filler content with five different percentages of the GRP-WP content (0%, 25%, 50%, 75% and 100% replacement by weight of the filler), was prepared to figure out which sample would produce the similar Marshall stability and flow values compared to the control samples while also satisfying specification limits. It was found that the samples with 4.5% binder content, 3.75% GRP-WP and 1.25% limestone filler content produced the results both satisfying the specification requirements and providing an optimum mix design. It is believed that use of GRP-WP waste in HMA production would be a very useful way of recycling GRP-WP.
  • [ X ]
    Öğe
    Utilization of rock dust as cement replacement in cement composites: An alternative approach to sustainable mortar and concrete productions
    (Elsevier, 2023) Dobiszewska, Magdalena; Bagcal, Orlando; Beycioglu, Ahmet; Goulias, Dimitrios; Koksal, Fuat; Plominski, Blazej; Urunveren, Husamettin
    Production of concrete is consuming significant amounts of raw materials, high level of energy, and is heavily dependent on fossil fuels. This induces significant harmful impact on the environment. Scientific research is being conducted worldwide on the possibility of using different waste by-products in the production of concrete, particularly as a substitute for cement clinker. Rock dust of different geological origin can be considered as potential alternative material that can be used in cement composites production. However, there are some conflicting findings concerning the effect of rock dusts as partial cement replacement on the physical and mechanical properties and durability of cement composites as reported in the literature. Thus, a comprehensive assessment and analysis are needed to evaluate the value of rock dust application as cement replacement in concrete production. This paper presents a comprehensive review of the findings from scientific articles concerning the use of rock dust of different geological origins in mortar and concrete productions. The effect of rock dusts as partial cement substitution on cementitious composites properties were analyzed particularly on the cement hydration, the concrete and mortar mixture properties, mechanical properties and durability. The impact of rock dust is mainly related to the filler effect i.e., due to modification of particle size distribution, heterogenious nucleation, and cement dilution. This effect is more significant when cement is substituted with a rock dust of greater fineness than cement. Partial replacement of cement with up to about 10-15% of rock powder does not deteriorate cement composite properties. However higher substitution leads to reduction of mechanical properties and cement composite durability decline.
  • [ X ]
    Öğe
    Utilization of rock dust as cement replacement in cement composites: An alternative approach to sustainable mortar and concrete productions
    (Elsevier, 2023) Dobiszewska, Magdalena; Bagcal, Orlando; Beycioglu, Ahmet; Goulias, Dimitrios; Koksal, Fuat; Plominski, Blazej; Urunveren, Husamettin
    Production of concrete is consuming significant amounts of raw materials, high level of energy, and is heavily dependent on fossil fuels. This induces significant harmful impact on the environment. Scientific research is being conducted worldwide on the possibility of using different waste by-products in the production of concrete, particularly as a substitute for cement clinker. Rock dust of different geological origin can be considered as potential alternative material that can be used in cement composites production. However, there are some conflicting findings concerning the effect of rock dusts as partial cement replacement on the physical and mechanical properties and durability of cement composites as reported in the literature. Thus, a comprehensive assessment and analysis are needed to evaluate the value of rock dust application as cement replacement in concrete production. This paper presents a comprehensive review of the findings from scientific articles concerning the use of rock dust of different geological origins in mortar and concrete productions. The effect of rock dusts as partial cement substitution on cementitious composites properties were analyzed particularly on the cement hydration, the concrete and mortar mixture properties, mechanical properties and durability. The impact of rock dust is mainly related to the filler effect i.e., due to modification of particle size distribution, heterogenious nucleation, and cement dilution. This effect is more significant when cement is substituted with a rock dust of greater fineness than cement. Partial replacement of cement with up to about 10-15% of rock powder does not deteriorate cement composite properties. However higher substitution leads to reduction of mechanical properties and cement composite durability decline.