Exposure of Portland-limestone cement – metakaolin paste to cold chloride-sulfate environment: NMR spectroscopy assessment of structural changes in hydrated phases and relation to chloride ingress

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378297%3A_____%2F23%3A00573017" target="_blank" >RIV/68378297:_____/23:00573017 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1007/978-3-031-33187-9_88" target="_blank" >https://doi.org/10.1007/978-3-031-33187-9_88</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/978-3-031-33187-9_88" target="_blank" >10.1007/978-3-031-33187-9_88</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Exposure of Portland-limestone cement – metakaolin paste to cold chloride-sulfate environment: NMR spectroscopy assessment of structural changes in hydrated phases and relation to chloride ingress

Popis výsledku v původním jazyce

The effect of sulfates on chloride ingress and microstructure in Portland-limestone cement – metakaolin paste was studied. Crystalline and amorphous phases were investigated with X-ray powder diffraction and solid-state nuclear magnetic resonance spectroscopy. Free chlorides were determinedwith ion chromatography. The influence of metakaolin on the microstructure and chloride binding was highlighted by comparing the material with pure Portland-limestone cement paste. The results showed that the high Al content in metakaolin increased the chloride binding ability of the binder and Al incorporation in the C–S–H phase. Close to the surface, metakaolin admixture contributed in greater polymerization of the silicate chains of C–S–H, while larger amounts of unreacted clinker were observed, compared to deeper parts. At higher depths, chlorides bound in the form of Friedel’s salt and free chlorides, were considerably reduced, attributed to refinement of the matrix. The presence of sulfates in the exposure solution affected chloride binding by inhibiting the formation of Friedel’s salt and increasing free chlorides in the pore solution. Moreover, sulfates decreased the polymerization of the silicate chains in the C–S–H of the Portland-limestone cement – metakaolin paste and reduced the hydration of clinker in pure Portland-limestone cement paste.

Název v anglickém jazyce

Exposure of Portland-limestone cement – metakaolin paste to cold chloride-sulfate environment: NMR spectroscopy assessment of structural changes in hydrated phases and relation to chloride ingress

Popis výsledku anglicky

The effect of sulfates on chloride ingress and microstructure in Portland-limestone cement – metakaolin paste was studied. Crystalline and amorphous phases were investigated with X-ray powder diffraction and solid-state nuclear magnetic resonance spectroscopy. Free chlorides were determinedwith ion chromatography. The influence of metakaolin on the microstructure and chloride binding was highlighted by comparing the material with pure Portland-limestone cement paste. The results showed that the high Al content in metakaolin increased the chloride binding ability of the binder and Al incorporation in the C–S–H phase. Close to the surface, metakaolin admixture contributed in greater polymerization of the silicate chains of C–S–H, while larger amounts of unreacted clinker were observed, compared to deeper parts. At higher depths, chlorides bound in the form of Friedel’s salt and free chlorides, were considerably reduced, attributed to refinement of the matrix. The presence of sulfates in the exposure solution affected chloride binding by inhibiting the formation of Friedel’s salt and increasing free chlorides in the pore solution. Moreover, sulfates decreased the polymerization of the silicate chains in the C–S–H of the Portland-limestone cement – metakaolin paste and reduced the hydration of clinker in pure Portland-limestone cement paste.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20501 - Materials engineering

Projekt

<a href="/cs/project/GC21-35772J" target="_blank" >GC21-35772J: Změny mikrostruktury směsných cementových past s vápencem na základě kombinovaného vlívu síranových a chloridových iontů</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

International RILEM Conference on Synergising Expertise towards Sustainability and Robustness of Cement-based Materials and Concrete Structures. SynerCrete’23

ISBN

978-3-031-33186-2

ISSN

2211-0844

e-ISSN

2211-0852

Počet stran výsledku

8

Strana od-do

966-973

Název nakladatele

Springer

Místo vydání

Cham

Místo konání akce

Milos Island

Datum konání akce

14. 6. 2023

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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