The aim of this work was to reduce the carbon footprint of cement concrete by using multi-component cement with a high content of blast furnace slag. The analysis consisted of comparing the properties of the concrete mix and the hardened concrete made of the CEM I 42.5 R-NA cement commonly used in Poland and the CEM III cement with a large amount of blast furnace slag. The tests used cement in a constant amount of 380 kg/m, granite aggregate of 2/8, 8/16, 16/22 mm and sand of 0/2 mm. As part of this project, detailed tests of the concrete mix and hardened concrete were carried out in terms of compressive, bending, fracture and frost resistance after 150 cycles of freezing and thawing, and the pore structure in hardened concrete was assessed according to PN-EN 480-11. The endurance tests were performed after 7, 28 and 90 days. On the basis of the obtained results, it was found that the highest compressive strengths above 70.2 MPa were obtained for concrete with CEM III, 64.5 MPa for concrete with CEM I. Additionally, for concrete with multi-component cement, smaller drops in compressive strength were obtained and a more favorable pore distribution in hardened concrete was obtained. Concrete intended for road surfaces can be made of both CEM I and CEM III cement, as they meet the requirements of the technical specifications for roads with heavy traffic of heavy vehicles.
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http://dx.doi.org/10.3390/ma15144998 | DOI Listing |
Materials (Basel)
January 2025
School of Civil and Architectural Engineering, Hunan Institute of Science and Technology, Yueyang 414000, China.
Ultra-high-performance concrete (UHPC) is a cement-based composite material characterised by exceptional strength, low porosity and high durability, making it highly promising for reinforcement engineering. Based on the theory of tangential modulus, a calculation method has been developed for the axial compression capacity of reinforced concrete (RC) medium and long columns strengthened with UHPC, using the constitutive relation of materials and internal and external force balance conditions. This study analysed the influence of UHPC reinforcement layer thickness, reinforced layer, reinforcement ratio, column slenderness ratio and initial load level of core columns on the bearing capacity of reinforced columns.
View Article and Find Full Text PDFLangmuir
January 2025
Institute of Concrete Structures and Building Materials, Gotthard-Franz-Str. 3, Karlsruhe 76131, Germany.
This paper investigates the impact of varying humidity conditions on the carbonation depth in hardened cement paste using a 3-dimensional microscale kinetic Monte Carlo (kMC) approach. The kMC algorithm effectively simulates the carbonation process by capturing the interplay between CO diffusion and relative humidity at the microscale, providing insights into macro trends that align with historical models. The study reveals that the maximum carbonation depth is achieved at relative humidity levels between 55 and 65%, where the balance between water and CO diffusion is optimized.
View Article and Find Full Text PDFHeliyon
January 2025
Mechanics Laboratory, Doctoral Training Unit in Engineering Sciences, Doctoral School of Fundamental and Applied Sciences, University of Douala, P.O. Box: 2701, Douala, Cameroon.
This study focuses on the influence of the partial substitution of cement by Cameroonian corn stover ash (CCSA) on the physical and mechanical behavior of concrete. For this, as materials used, one has first the corn stovers coming from the Bandjoun town in the Koung-khi division, in the West region of Cameroon, which are used to obtain the ashes, while the sand used, came from the Sanaga River in the coastal region of Cameroon. In order to obtain the CCSA, the corn stover is calcined in an oven at 600 °C for 6 h and then characterized; the characterization included infrared spectrometry, X-ray fluorescence spectrometry, fineness of grinding, and absolute density.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Architectural and Construction Design, Faculty of Architecture, Wrocław University of Science and Technology, Politechnika Wrocławska 27, 50-370 Wrocław, Poland.
This research presents a proposal for alkali-activated permeable concrete composites with the use of industrial by-products, including ground granulated blast-furnace slag (GGBS) and waste-foundry sand, as well as agro-desecrate product, i.e., sugarcane bagasse ash (SBA).
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Institute of Optoelectronics, Military University of Technology, 00-908 Warsaw, Poland.
The paper presents experimental studies on the influence of a simultaneous, appropriately proportioned combination of microsilica and fly ash additives on the physical and mechanical properties of ultra-high-performance concretes (UHPCs). Concrete mixtures with the addition of microsilica in the amount of 6.7-14.
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