scholarly journals Phase Assemblage, Microstructure and Shrinkage of Cement Paste during Carbonation at Different Relative Humiditiesn

2021 ◽  
Vol 19 (6) ◽  
pp. 687-699
Author(s):  
Yuya Suda ◽  
Jun Tomiyama ◽  
Tsuyoshi Saito ◽  
Tatsuhiko Saeki
Keyword(s):  
Cement Paste ◽  
Phase Assemblage

Phase assemblage and microstructure of cement paste subjected to enforced, wet carbonation

2020 ◽  
Vol 130 ◽  
pp. 105990 ◽  
Author(s):  
Maciej Zajac ◽  
Jørgen Skibsted ◽  
Jan Skocek ◽  
Pawel Durdzinski ◽  
Frank Bullerjahn ◽  
...  
Keyword(s):  
Cement Paste ◽  
Phase Assemblage

scholarly journals Clays as SCM – Reactivity of Uncalcined Kaolinite and Bentonite, and Impact on Phase Assemblage and Strength Development of PC Mortars

2019 ◽  
Vol 60 (1) ◽  
pp. 13-30
Author(s):  
Mette Rica Geiker ◽  
Emmanuel Gallucci
Keyword(s):  
Cement Paste ◽  
Chemical Reactivity ◽  
Engineering Properties ◽  
Strength Development ◽  
Phase Assemblage ◽  
Clay Particles ◽  
Compressive Strength Development ◽  
The Impact ◽  
Detrimental Impact ◽  
Porosity Measurements

Abstract The impact of substitution of cement paste with uncalcined clay (bentonite and kaolinite) in the range of 5% by volume of paste on the development of hydration and properties of mortar was investigated. Two issues were addressed, the expected filler effect of the dispersed sub-micron clay particles, and the possible chemical reactivity of the clay. The study indicated that Portland cement paste may be modified by addition of well dispersed clay and that the impact includes accelerated cement hydration as well as altered distribution of products. Compressive strength development was accelerated, but later age strength was reduced, especially for the bentonite mixes. In contrast, microscopic porosity measurements indicated no detrimental impact on the coarse capillary porosity. The investigation indicates that for durability related engineering properties, the application of uncalcined clay might be a potential means for reduction of the clinker factor in concrete in support of sustainability.

scholarly journals Towards the Understanding of the pH Dependency of the Chloride Binding of Portland Cement Pastes

2018 ◽  
Vol 58 (1) ◽  
pp. 143-162 ◽  
Author(s):  
Alisa Machner ◽  
Petter Hemstad ◽  
Klaartje De Weerdt
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Considerable Increase ◽  
Phase Assemblage ◽  
Chloride Binding ◽  
Nacl Solution ◽  
Cement Pastes ◽  
Ph Dependency ◽  
Decreasing Ph ◽  
Portland Cement Paste

Abstract Hydrated Portland cement paste exposed to a NaCl solution was acidified by adding HCl in small steps, gradually lowering the pH. The chloride binding of the cement paste changed as a function of the pH. For the range of pH from 13.2 to 12.2, decreasing pH resulted in a considerable increase in the chloride binding. At a pH of 11, the cement paste showed almost no chloride binding. In order to explain the changes in chloride binding upon lowering the pH, the phase assemblage was investigated with SEM-EDS, TGA and XRD and compared to a thermodynamic modelling.

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