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MARKO, M. HRUBÝ, P. JANČA, M. KŘIKALA, J. HAJZLER, J. ŠOUKAL, F. VOJTÍŠEK, J. DOLEŽAL, M.
Originální název
Monitoring of Ion Mobility in the Cement Matrix to Establish Sensitivity to the ASR Caused by External Sources
Typ
článek v časopise ve Web of Science, Jimp
Jazyk
angličtina
Originální abstrakt
The possibility of the formation of an alkali-silicate reaction (ASR) is a crucial issue for the service life of concrete. The coexistence of key parameters such as the presence of alkalis, reactive SiO2, humidity, and temperature predetermine the possibility of its formation and application. When an ASR gel forms, it results in the concreting cracking and spalling as well as in the deterioration of its overall properties. The risk of ASR depends on the concentration of alkalis and their mobility, which influence their ability to penetrate the concrete. The objective of this study was to determine the ionic mobility of not only Na+ and K+, but Ca2+ as well, from external sources (0.5 and 1.0 mol/L solutions of Na/K carbonate, nitrate, and hydroxide) to a cementitious matrix as the precursor for ASR. The concentrations of ions in both the immersion solutions (ICP) and the cementitious matrix itself (SEM-EDX) were studied as a function of time, from 0 to 120 days, for leaching, and according to temperature (25 and 40 degrees C). The reaction products were characterized using SEM-EDX. Different diffusion rates and behavior were observed depending on the anion type of the external alkali source. Both sodium and potassium ions in all the three environments studied, namely carbonate, hydroxide, and nitrate, penetrated into the composite and further into its structure by different mechanisms. The action of hydroxides, in particular, transformed the original hydration products into calcium-silicate-hydrate (CASH) or ASR gel, while nitrates crystallized in pores and did not cause any changes in the hydration product. The driving force was the increased temperature of the experiment as well as the increased concentration of the solution to which the test specimen was exposed.
Klíčová slova
alkali-silicate reaction; diffusion; ionic mobility; cement; degradation
Autoři
MARKO, M.; HRUBÝ, P.; JANČA, M.; KŘIKALA, J.; HAJZLER, J.; ŠOUKAL, F.; VOJTÍŠEK, J.; DOLEŽAL, M.
Vydáno
6. 7. 2022
Nakladatel
MDPI
Místo
BASEL
ISSN
1996-1944
Periodikum
Materials
Ročník
15
Číslo
14
Stát
Švýcarská konfederace
Strany od
1
Strany do
19
Strany počet
URL
https://www.mdpi.com/1996-1944/15/14/4730
Plný text v Digitální knihovně
http://hdl.handle.net/11012/208169
BibTex
@article{BUT177659, author="Michal {Marko} and Petr {Hrubý} and Martin {Janča} and Jakub {Křikala} and Jan {Hajzler} and František {Šoukal} and Jan {Vojtíšek} and Martin {Doležal}", title="Monitoring of Ion Mobility in the Cement Matrix to Establish Sensitivity to the ASR Caused by External Sources", journal="Materials", year="2022", volume="15", number="14", pages="1--19", doi="10.3390/ma15144730", issn="1996-1944", url="https://www.mdpi.com/1996-1944/15/14/4730" }