Standardless Energy dispersive spectroscopy (EDS) on polished samples of Portland cement clinker is routinely performed both for unhydrated phases as well as in cement pastes. Typically, the calcium to silica ratio is investigated. EDS analyses are highly dependent on the polishing quality of the sample. It is thus worth studying the Ca/Si ratios of cement phases in a clinker since they can be used as a reference. Indeed, alite (CaSiO or CS in cement chemistry notation) and belite (CaSiO or CS) should have an atomic Ca/Si ratio of 3 and 2, respectively. EDS carried out under the scanning electron microscope (SEM) is routinely used on polished samples to assess the composition of such phases. In the present study, Ca/Si ratios are investigated on a commercial clinker polished at various steps (6, 3, 1 and 0.25 µm diamond pastes, 0.05 µm alumina). All along the polishing process, ratios are coherent with theoretical ones and with the reference ones obtained by electron probe microanalysis (EMPA) in the present study.
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http://dx.doi.org/10.1016/j.micron.2022.103266 | DOI Listing |
Materials (Basel)
January 2025
College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, Urumqi 830052, China.
Hydraulic structures are frequently subjected to soft-water or acidic environments, necessitating serious consideration of the long-term effects of calcium leaching on the durability of concrete structures. Three types of common Portland cement (ordinary Portland cement, moderate-heat cement, and low-heat cement) paste samples widely applied to hydraulic concrete were immersed in a 6 mol/L NHCl solution to simulate accelerated calcium leaching behavior. The mass loss, porosity, leaching depth, compressive strength, and Ca/Si ratio of the three types of pastes were measured at different immersion stages (0, 14, 28, 56, 91, 140, and 180 days).
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January 2025
Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Campus la Nubia, Km 9 via al Magdalena, Manizales 170007, Colombia.
In this study, we research the innovative application of multi-walled carbon nanotubes (MWCNTs) as corrosion inhibitors in Portland cement embedded steel. The physicochemical properties of the dispersion solutions were evaluated, varying the storage time, to analyze their effect on corrosion resistance. Using a dispersion energy of 440 J/g and a constant molarity of 10 mM, stable dispersions were achieved for up to 3 weeks.
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January 2025
Department of Structural Materials and Construction Chemistry, University of Kassel, 34117 Kassel, Germany.
The initial investigation evaluates the feasibility of ultra high performance concrete (UHPC) as a material for reusable molds in aluminum casting. Two specific UHPC formulations were investigated: one based on ordinary Portland cement (OPC) and another utilizing alkali-activated materials (AAM). The study focused on investigating the surface through roughness measurements and the thermal durability through repeated casting cycles.
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December 2024
School of Engineering, Computing and Mathematics, University of Plymouth, Plymouth PL4 8AA, UK.
Geopolymer concrete is a sustainable construction material and is considered as a promising alternative to traditional Portland cement concrete. However, there is still not much research on the effective properties and damage behavior of geopolymer concrete with consideration of its heterogeneous characteristics by means of mesoscale models combined with the regularized microplane damage model. Here, in this research, an easy and simpler approach for generating concrete mesoscale models and characterizing the angular characteristics of aggregate particles is presented.
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December 2024
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Gasification slag is the solid waste produced in the process of coal gasification. China produces approximately 30 million tons of gasification slag every year, which urgently needs to be recycled in an efficient and sustainable way. This paper discusses the feasibility of using gasification slag as a supplementary cementitious material (SCM).
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