% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@PHDTHESIS{SchulteHolthausen:765936,
author = {Schulte Holthausen, Robert Wilhelm},
othercontributors = {Raupach, Michael and Blümich, Bernhard and Schüttrumpf,
Holger},
title = {{E}valuation of the pore structure of concrete using
single-sided $^{1}${H} nuclear magnetic resonance
relaxometry},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2019-07752},
pages = {1 Online-Ressource : Illustrationen, Diagramme},
year = {2019},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2019, Kumulative Dissertation},
abstract = {In recent years, there has been growing interest in the use
of proton nuclear magnetic resonance (1H NMR) relaxometry to
obtain information on porosity and pore structure of
cementitious materials. Investigations were mostly limited
to white cement pastes and the use of closed magnet setups.
In this thesis including the appended five papers, a
comprehensive approach is followed to expand the existing
knowledge for quantitative measurements of porosity and pore
structure of concrete using single-sided 1H NMR. Differences
in measurement and results due to the single-sided
measurement setup, the influence of paramagnetic iron as
well as aggregates are investigated and discussed.
Single-sided 1H NMR allows the quantification of all liquid
pore water in cement stone, mortar, and concrete without the
need for sample preparation, destruction or a
material-dependent calibration. Results from cement paste
samples show that paramagnetic iron concentration increases
surface relaxation rate linearly. This allows a transfer of
the existing relaxation time to pore size conversions from
white cement to ordinary Portland cement and thus, a
quantified measurement of pore sizes. The influence of
crystalline compounds, such as Portlandite and Ettringite,
on the received signal is evaluated using T1-T2 experiments.
Based on the results, partially new interpretations for
off-diagonal signals in T1-T2 distributions have been
developed. Aggregates in mortars and concrete reduce the
amount of porous cement stone and alter the overall pore
size distribution due to the development of the interfacial
transition zone. This effect, though, is not as pronounced
as expected based on past investigations. The immense
influence of moisture on the pore structure of dried and
rewetted mortars might explain this and other discrepancies
found in the past for pore sizes and its influence on
material properties. Single-sided 1H NMR is used to
investigate the influence of fresh concrete pressure as well
as an extreme superficially applied temperature exposure on
concrete cover porosity. Prospective future usage of
singlesided 1H NMR in research, material testing, and
on-site investigations is outlined.},
cin = {311310},
ddc = {624},
cid = {$I:(DE-82)311310_20180808$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2019-07752},
url = {https://publications.rwth-aachen.de/record/765936},
}
guest ::