Detail publikace

Monitoring of Ion Mobility in the Cement Matrix to Establish Sensitivity to the ASR Caused by External Sources

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

19

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"
}