Artykuły naukowe (WBiIŚ)

Stały URI dla kolekcji

https://oa.zut.edu.pl/handle/20.500.12539/40

Przeglądaj

Przeglądaj Artykuły naukowe (WBiIŚ) wg Temat "Concrete"

Teraz wyświetlane 1 - 2 z 2
  • Miniatura
    PozycjaOpen Access
    Insight into the microstructural and durability characteristics of 3D printed concrete: Cast versus printed specimens
    (Elsevier BV, 2022-07-16) Sikora, Pawel; Techman, Mateusz; Federowicz, Karol; El-Khayatt, Ahmed M.; Saudi, H.A.; Abd Elrahman, Mohamed; Hoffmann, Marcin; Stephan, Dietmar; Chung, Sang-Yeop; Faculty of Civil and Environmental Engineering, West Pomeranian University of Technology in Szczecin, Poland; Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University, (IMSIU), Riyadh, Saudi Arabia; Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, 13759 Cairo, Egypt; Department of Physics, Faculty of Science, Al-Azhar University, Women Branch, Nasr City, Cairo, Egypt; Structural Engineering Department, Mansoura University, Mansoura City 35516, Egypt; Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology in Szczecin, Poland; Building Materials and Construction Chemistry, Technische Universität Berlin, Germany; Department of Civil and Environmental Engineering, Sejong University, Seoul 05006, Republic of Korea
    This study presents the comparison of microstructural and durability characteristics of 3D printed concrete (3DPC) depending on its production method (printing or casting). Printed samples with different numbers of layers, as well as a cast specimen with an identical mix composition, were produced and compared, with their microstructural pore and solid characteristics quantitatively and qualitatively investigated. For this purpose, scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and X-ray micro-computed tomography (micro-CT) were utilized to evaluate the microstructures of the 3DPC. In particular, quantitative approaches using micro-CT data were newly proposed for a better understanding of the microstructural characteristics of 3DPC. Moreover, their durability-related characteristics and transport properties, including freeze-thaw and thermal resistance, were examined and compared. Despite noticeable differences between the microstructures of the printed and cast specimens, including their anisotropic and inter-layer porosity and heterogeneity, confirmed by MIP, SEM and micro-CT, no significant differences in the transport (capillary water porosity and water sorptivity) or durability-related properties (frost and thermal attack) were found. This was due to the dense and homogenous microstructure of 3DPC, which is attributable to the high binder content and low w/b of the mixture. Moreover, the newly proposed evaluation provided reasonable quantitative and qualitative characteristics, which can be used to demonstrate and predict the material properties of 3DPC.
  • Miniatura
    PozycjaOpen Access
    Seawater-mixed concretes containing natural and sea sand aggregates – A review
    (Elsevier BV, 2023) Rathnarajan, Sundar; Sikora, Paweł; West Pomeranian University of Technology in Szczecin. Faculty of Civil and Environmental Engineering; West Pomeranian University of Technology in Szczecin. Faculty of Civil and Environmental Engineering
    In light of global warming and the rising urban population across the world, freshwater is becoming a scarce commodity. Freshwater consumption in the production of concrete makes up a significant (9%) share of total freshwater withdrawal for industrial purposes. Among the alternative sources of water for concrete production, seawater involves minimal processing, besides screening debris with filters. Other options, such as the use of wastewater from industrial effluent or desalination of hard waters, require a significant amount of energy, which add to overall concrete production emissions. Many efforts have been made by researchers in the last decades to understand the behaviour of seawater-mixed and sea sand concretes (SW-SS). The present work evaluates the early-age hydration, fresh, mechanical, and durability performance of SW-SS concretes and the corrosion characteristics of embedded reinforcement in them. The authors also summarize mitigation measures recommended in the literature for improving the anti-corrosion performance of SW-SS concretes, by partial substitution of supplementary cementitious materials (SCMs), the inclusion of alternative reinforcements (such as stainless steel and fibre reinforced polymer bars), the incorporation of corrosion inhibitors, and the adaptation of cathodic prevention measures. Finally, the article highlights the possible challenges to, opportunities for and potential applications of SW-SS concretes in the near future, so as to combat the freshwater crisis in nations suffering severe water stress.