D-4 Quantitative In-Situ X-ray Diffraction Analysis of Early Hydration of Portland Cement at Defined Temperatures

2008 ◽  
Vol 23 (2) ◽  
pp. 175-175 ◽  
Author(s):  
C. Hesse ◽  
F. Goetz-Neunhoeffer ◽  
J. Neubauer ◽  
M. Braeu ◽  
P. Gaeberlein ◽  
...  
2009 ◽  
Vol 24 (2) ◽  
pp. 112-115 ◽  
Author(s):  
C. Hesse ◽  
F. Goetz-Neunhoeffer ◽  
J. Neubauer ◽  
M. Braeu ◽  
P. Gaeberlein

Investigation into the early hydration of Portland cement was performed by in situ X-ray diffraction (XRD). Technical white cement was used for the XRD analysis on a D5000 diffractometer (Siemens). All diffraction patterns of the in situ measurement which were recorded up to 22 h of hydration at defined temperatures were analyzed by Rietveld refinement. The resulting phase composition was transformed with respect to free water and C-S-H leading to the total composition of the cement paste. The hydration reactions can be observed by dissolution of clinker phases as well as by the formation of the hydrate phases ettringite and portlandite. With increasing temperatures the reactions proceed faster. The formation of ettringite is directly influenced by the rate of dissolution of anhydrite and tricalcium aluminate (C3A). The beginning of the main period of hydration is marked by the start of portlandite formation. The experiments point out that a quantitative phase analysis of the cement hydration is feasible with standard laboratory diffractometers.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.


2019 ◽  
Vol 92 (7) ◽  
pp. 1013-1019 ◽  
Author(s):  
P. A. Novikov ◽  
A. E. Kim ◽  
K. A. Pushnitsa ◽  
Wang Quingsheng ◽  
M. Yu. Maksimov ◽  
...  

2016 ◽  
Vol 120 (27) ◽  
pp. 14984-14990 ◽  
Author(s):  
Qin Pan ◽  
Ching-Chang Chung ◽  
Nanfei He ◽  
Jacob L. Jones ◽  
Wei Gao

CrystEngComm ◽  
2018 ◽  
Vol 20 (22) ◽  
pp. 3105-3116 ◽  
Author(s):  
Roman Svoboda ◽  
Roman Bulánek ◽  
Dušan Galusek ◽  
Roghayeh Hadidimasouleh ◽  
Yadolah Ganjkhanlou

Differential scanning calorimetry and in situ X-ray diffraction analysis were used to study the products and mechanism of crystal formation in VOx–ZrO2 ceramics.


2005 ◽  
Vol 275 (1-2) ◽  
pp. e1793-e1798 ◽  
Author(s):  
L. O’Mahony ◽  
D. Zemlyanov ◽  
M. Mihov ◽  
T. Curtin ◽  
B.K. Hodnett

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