Monitoring the internal swelling in cementitious mortars with single-sided 1H nuclear magnetic resonance

Holthausen, Robert Schulte; Raupach, Michael

doi:10.1016/j.cemconres.2018.05.021

Cited by 61 publications

(21 citation statements)

References 25 publications

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“…In addition, analysis of single-sided NMR signal revealed the redistribution of water among interlayer pores, gel pores, inter-hydrate pores, and capillary pores. Continuous monitoring on capillary absorption also supports redistribution of water into gel pores and then interlayer pores at time scales ranging from roughly 1 h to several weeks, which makes C-S-H gels swell and reduces the volume of coarse pores [109]. Given the water redistribution and swelling of C-S-H gels upon wetting, expansion of CBMs is also expected…”

Section: Swelling Of C-s-h Gels Upon Wettingmentioning

confidence: 88%

Water sensitivity of cement‐based materials

Zhang

Wang

et al. 2021

J Am Ceram Soc

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Cement-based materials are the most widely used construction materials on the planet. Cementbased materials play a fundamental role in modern civilization and will for the foreseeable future.Although great efforts have been devoted to discovering the behaviors and optimizing their performances, several long-standing controversies persist for the fundamental water-related properties of cement-based materials, which hinder theoretical researches and mislead technological developments. Inspired by the decreasing water permeability of clay-bearing rocks, the term "water sensitivity" in geophysics is borrowed and proposed for cement-based materials. The lamellar structure of negatively charged nanoparticles is responsible for swelling in clay-based reservoir rocks. Amorphous calcium silicate hydrate gels in cement-based materials have similar microstructural characteristics. They probably swell upon wetting and contract upon drying, making the pore structure of cement-based materials dependent on water content. More importantly, several unexplained behaviors of cement-based materials can be rationalized using water sensitivity.Thorough exploration of both the micro-structural characteristics and performances validate the use of water sensitivity for cement-based materials. Because water participates in or regulates almost all physical and chemical processes of cement-based materials, water sensitivity can be a part of the interpretations of almost all of their properties and performances.

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Section: Swelling Of C-s-h Gels Upon Wettingmentioning

confidence: 88%

Water sensitivity of cement‐based materials

Zhang

Wang

et al. 2021

J Am Ceram Soc

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“…LF-NMR aims to analyze the composition of a test sample based on the nuclear magnetic resonance characteristics of the hydrogen nucleus, low field nuclear magnetic resonance spectroscopy was carried out on the concrete specimens at the curing ages of 1 d, 3 d, 7 d, 14 d, and 28 d, the CPMG pulse sequence data were collected, and perform inversion calculations through T 2 inversion software. Thus, a spectrum composed of the LF-NMR signal amplitude and relaxation time of different types of water in the concrete test block is obtained [ 26 ].…”

Section: Experimental Programmentioning

confidence: 99%

Early-Age Hydration Reaction and Strength Formation Mechanism of Solid Waste Silica Fume Modified Concrete

et al. 2021

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Solid waste silica fume was used to replace fly ash by different ratios to study the early-age hydration reaction and strength formation mechanism of concrete. The change pattern of moisture content in different phases and micro morphological characteristics of concrete at early age were analyzed by low field nuclear magnetic resonance (LF-NMR) and scanning electron microscope (SEM). The results showed that the compressive strength of concrete was enhanced optimally when the replacement ratio of solid waste silica fume was 50%. The results of LF-NMR analysis showed that the water content of modified concrete increased with the increase of solid waste silica fume content. The compressive strength of concrete grew faster within the curing age of 7 d, which means the hydration process of concrete was also faster. The micro morphological characteristics obtained by SEM revealed that the concrete was densest internally when 50% fly ash was replaced by the solid waste silica fume, which was better than the other contents.

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“…Bei der Probenherstellung wurden aus größeren Betonblöcken Normprismen mit den Maßen 40 × 40 × 160 mm 3 In den vergangenen Jahren wurde am Institut für Baustoffforschung (ibac) der RWTH Aachen ein systematischer Ansatz verfolgt, um die mittels geschlossener Kernspinresonanzgeräte für Weißzementstein entwickelten Untersuchungstechniken auf den Einsatz einseitiger Messgeräte und Betonproben zu übertragen [20]. Hierbei erlaubt die gemessene Signalamplitude, nach entsprechender Normierung, direkte Rückschlüsse auf die Porosität [20,21]. Auf Basis der Relaxationszeiten konnten auch für Portlandzemente plausible Porengrößen abgeschätzt werden [20,22].…”

Section: Auslaugung Von Betonprobenunclassified

Zerstörungsfreie Bestimmung der Auslaugung von Beton mittels einseitiger Wasserstoff‐Kernspinresonanz

et al. 2020

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Der dauerhafte Kontakt zwischen Beton und Trinkwasser wird i. Allg. als unkritisch für Betonoberflächen angesehen. Im Falle besonders kalkarmer Wässer kann jedoch ein kombinierter Lösungs-/Diffusionsprozess [1-4] stattfinden, der Betonoberflächen empfindlich schädigen kann. Bei dem als Auslaugung oder hydrolytische Korrosion bezeichneten Prozess finden drei aufeinanderfolgende Prozesse statt [5]: (A) Zunächst wird das Portlandit im Zementstein aufgelöst. (B) In einem zweiten Schritt wird Calcium aus den festigkeitsbildenden Calcium-Silikat-Hydratphasen (CSH) des Zementsteins herausgelöst und dieser "calciumverarmt". (C) Zuletzt wird der Zementstein gänzlich zersetzt und es verbleibt ein weiches Hydroxidgel auf der Oberfläche [4], das ohne größere mechanische Einwirkung abgetragen werden kann [5]. Diese Auslaugungsprozesse sind alle drei von einem Anstieg der Materialporosität begleitet [6]. Durch den Abbau von Portlandit entsteht zusätzlicher Porenraum bei einem Porendurchmesser um 10 nm [7] sowie aufgrund der Calciumverarmung der CSH-Phasen bei größeren Porendurch-Keywords concrete; durability; leaching; drinking water; X TWB ; deionized water; cement stone, single-sided 1 H nuclear magnetic resonance

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Monitoring the internal swelling in cementitious mortars with single-sided 1H nuclear magnetic resonance

Cited by 61 publications

References 25 publications

Water sensitivity of cement‐based materials

Water sensitivity of cement‐based materials

Early-Age Hydration Reaction and Strength Formation Mechanism of Solid Waste Silica Fume Modified Concrete

Zerstörungsfreie Bestimmung der Auslaugung von Beton mittels einseitiger Wasserstoff‐Kernspinresonanz

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