Characterization of reactive MgO-modified calcium sulfoaluminate cements upon carbonation

2021 ◽  
Vol 146 ◽  
pp. 106484
Author(s):  
Joonho Seo ◽  
H.N. Yoon ◽  
Seonhyeok Kim ◽  
Zhen Wang ◽  
Taegeon Kil ◽  
...  
Keyword(s):  
Calcium Sulfoaluminate

Characterization of Micro-Pore Structure in Novel Cement Matrices

2014 ◽  
Vol 1712 ◽  
Author(s):  
Seyoon Yoon ◽  
Isabel Galan ◽  
Kemal Celik ◽  
Fredrik P. Glasser ◽  
Mohammed S. Imbabi
Keyword(s):  
Portland Cement ◽  
Pore Structure ◽  
Engineering Properties ◽  
Calcium Sulfoaluminate ◽  
Pore Structures ◽  
Porosity And Permeability ◽  
Experimental Protocols ◽  
Novel Processing ◽  
Main Component

ABSTRACTCalcium sulfoaluminate (CSA) cements are being developed using a novel processing method having as its objective lowering specific CO2 emissions by ∼50% relative to a Portland cement benchmark. We need to be able to measure the properties of the products. Porosity and permeability measurements help define the engineering properties but their quantification is influenced by the choice of experimental protocols. In the present study we used ordinary Portland cement (PC) paste as a benchmark and hydrated ye’elimite, which is a main component of CSA cements, to understand its pore structure. We report on the use of synchrotron-sourced radiation for µCT (Computerized Tomography) and 3D image re-construction of the internal micro-pore structure of PC and ye’elimite-gypsum pastes. As a comparison, porosity and permeability measurements were traditionally obtained using Mercury Intrusion Porosimetry (MIP). The Mori-Tanaka method and the polynomial statistical model were used to analyze the effects of different 3-D micro-pore structures on mechanical properties. The results show that e micro-pore structures differ considerably between PC and ye’elimite pastes and their bulk modulus is significantly affected by the shapes of their micro-pore structures.

scholarly journals Electrochemical Performance of Steel Embedded in CSA Concrete and Its Interfacial Microstructure

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Meimei Song ◽  
Qiu Li ◽  
Ke Wu ◽  
Yihua Dou
Keyword(s):  
Corrosion Resistance ◽  
Hydration Product ◽  
Interfacial Microstructure ◽  
Interfacial Zone ◽  
Low Carbon ◽  
Calcium Sulfoaluminate ◽  
Galvanostatic Polarization ◽  
Relationship Of ◽  
The Relationship

Calcium sulfoaluminate cement (CSA) is a low-carbon cementitious material that significantly reduces alkalinity and produces calcium hydroxide-free (CH-free) matrix environment in comparison to ordinary Portland cement (OPC). It might be, however, less efficient towards the passivation of steel in concrete and further investigation before widespread adoption is required. In this project, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) on polished samples was employed to provide the interfacial characterization of steel reinforced CSA concrete and study the relationship of interfacial quality and corrosion resistance of the embedded steel. The galvanostatic polarization behavior indicates that the steel embedded in CSA concrete remains passive for 28 days in absence of Cl− ions and carbonation. Microstructure analysis has shown that there is an Al-enriched layer at interfacial zone in CSA concrete with the main hydration product of AH3, which is also alkaline and is expected to improve the steel passivity. Furthermore, the interfacial zone has markedly reduced porosity compared to the bulk matrix, which leads to reduced possibility of current flow between anode and cathode and therefore improves the corrosion resistance of the embedded reinforcement.

Local Al network and material characterization of belite-calcium sulfoaluminate (CSA) cements

2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Joonho Seo ◽  
Solmoi Park ◽  
Seonhyeok Kim ◽  
H. N. Yoon ◽  
H. K. Lee
Keyword(s):  
Material Characterization ◽  
Calcium Sulfoaluminate

Nanostructural characterization of Al(OH) 3 formed during the hydration of calcium sulfoaluminate cement

2018 ◽  
Vol 101 (9) ◽  
pp. 4262-4274 ◽  
Author(s):  
Yangyang Zhang ◽  
Jun Chang ◽  
Jiuye Zhao ◽  
Yanfeng Fang
Keyword(s):  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate

scholarly journals Rheological and hydration characterization of calcium sulfoaluminate cement pastes

2012 ◽  
Vol 34 (5) ◽  
pp. 684-691 ◽  
Author(s):  
Marta García-Maté ◽  
Isabel Santacruz ◽  
Ángeles G. De la Torre ◽  
Laura León-Reina ◽  
Miguel A.G. Aranda
Keyword(s):  
Calcium Sulfoaluminate Cement ◽  
Cement Pastes ◽  
Calcium Sulfoaluminate

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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