Effect of vacuum and Focused Ion Beam generated heat on fracture properties of hydrated cement paste

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F19%3A00333744" target="_blank" >RIV/68407700:21110/19:00333744 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/19:00540578

Výsledek na webu

<a href="https://doi.org/10.1016/j.cemconcomp.2019.03.027" target="_blank" >https://doi.org/10.1016/j.cemconcomp.2019.03.027</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cemconcomp.2019.03.027" target="_blank" >10.1016/j.cemconcomp.2019.03.027</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Effect of vacuum and Focused Ion Beam generated heat on fracture properties of hydrated cement paste

Popis výsledku v původním jazyce

The paper focuses on quantifying of vacuum and heat influence as unavoidable effects that appear during preparation and in-situ monitoring of micromechanical performance of cement pastes. Experimental tests at micrometer scale employ microscopic techniques of Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB). High vacuum is applied to samples during SEM-FIB procedures causing dessication and densification of primary cement paste constituents, the CSH gels. Collapse of pores and microstructural packing leads to their local stiffening and change in their fracture properties compared to usual partially saturated conditions of atmospheric pressures. The effect of vacuum is quantified for individual paste constituents in terms of their elastic moduli, tensile strengths and fracture energies measured on 15–20 μm long cantilever micro-beams inside SEM chamber. It was found that application of vacuum in SEM increases elastic moduli of inner and outer products by ~30%, tensile strength rises 2.3–2.5 times. The effect of local heating due to ionic interactions during FIB milling is studied by means of micromechanical measurements on micro-beams and finite element (FE) numerical model. It is shown that high energy milling (30 kV, 30 nA) causes substantial microstructural and subsequent mechanical changes leading to further stiffening and tensile strength increase in the micrometer scale. The effect originates from phase changes caused by elevated temperatures under the ion beam that can be locally very high (thousands of K according to the simplified FE model). The paper also reports micromechanical response received by low energy milling for which microstructural changes due to increased temperature are restricted to very small volumes and can be assumed to be negligible with respect to the micro-beam dimensions.

Název v anglickém jazyce

Effect of vacuum and Focused Ion Beam generated heat on fracture properties of hydrated cement paste

Popis výsledku anglicky

The paper focuses on quantifying of vacuum and heat influence as unavoidable effects that appear during preparation and in-situ monitoring of micromechanical performance of cement pastes. Experimental tests at micrometer scale employ microscopic techniques of Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB). High vacuum is applied to samples during SEM-FIB procedures causing dessication and densification of primary cement paste constituents, the CSH gels. Collapse of pores and microstructural packing leads to their local stiffening and change in their fracture properties compared to usual partially saturated conditions of atmospheric pressures. The effect of vacuum is quantified for individual paste constituents in terms of their elastic moduli, tensile strengths and fracture energies measured on 15–20 μm long cantilever micro-beams inside SEM chamber. It was found that application of vacuum in SEM increases elastic moduli of inner and outer products by ~30%, tensile strength rises 2.3–2.5 times. The effect of local heating due to ionic interactions during FIB milling is studied by means of micromechanical measurements on micro-beams and finite element (FE) numerical model. It is shown that high energy milling (30 kV, 30 nA) causes substantial microstructural and subsequent mechanical changes leading to further stiffening and tensile strength increase in the micrometer scale. The effect originates from phase changes caused by elevated temperatures under the ion beam that can be locally very high (thousands of K according to the simplified FE model). The paper also reports micromechanical response received by low energy milling for which microstructural changes due to increased temperature are restricted to very small volumes and can be assumed to be negligible with respect to the micro-beam dimensions.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20101 - Civil engineering

Projekt

<a href="/cs/project/GA17-05360S" target="_blank" >GA17-05360S: Lomové vlastnosti amorfních a krystalických materiálů stanovené pomocí nanoindentace a fokusovaného iontového svazku v malém měřítku</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Cement and Concrete Composites

ISSN

0958-9465

e-ISSN

1873-393X

Svazek periodika

100

Číslo periodika v rámci svazku

July

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

139-149

Kód UT WoS článku

000468708900014

EID výsledku v databázi Scopus

2-s2.0-85064738841