Analysis of moisture migration in concrete at high temperature through in-situ neutron tomography

Dauti, Dorjan; Tengattini, Alessandro; Pont, Stefano Dal; Toropovs, Nikolajs; Briffaut, Matthieu; Weber, Benedikt

doi:10.1016/j.cemconres.2018.06.010

Cited by 77 publications

(72 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A peculiar property of neutron imaging (as opposed for example to X-rays) is that neutrons have a particularly high interaction with hydrogen and its compounds, lending itself as an ideal tool for the study of the evolving moisture profile. A notable case is that of Dauti et al [18] where a three-dimensional, real-time investigation of moisture transport in heated concrete is carried out. Therein, the influence of aggregate sizes is revealed, and the existence of moisture accumulation (moisture clog) behind the drying front [5] is suggested.…”

Section: Introductionmentioning

confidence: 99%

“…Therein, the influence of aggregate sizes is revealed, and the existence of moisture accumulation (moisture clog) behind the drying front [5] is suggested. Another relevant observation deriving from Dauti et al [18] is that the lateral insulation of the sample, which follows the standard protocol (aluminum tape and rock-wool), is not sufficient to ensure the commonly assumed uni-directional flow of moisture. Most experimental studies nonetheless rely on the assumption that this procedure suffices for imposing a one-directional heat-moisture flux.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives

Tengattini

Pont

Sleiman

et al. 2020

Strain

Self Cite

View full text Add to dashboard Cite

Concrete has a tendency to spall, that is, to eject layers when subjected to high temperatures. This is an erratic phenomenon, and our understanding of the underlying physical process is still limited. A driving process is moisture transfer, whose experimental investigation has so far mostly been limited to macroscopic or point-wise observations, limiting both our understanding and the validation of the proposed models. In this paper, a non-contact technique, neutron imaging, is used to extract a the full-field distribution of moisture in 3D and in real time, while the concrete is heated at high temperatures. This reveals a number of processes often underestimated or ignored in the traditional experimental approaches reported in the literature. Notably, the effect on the evolving moisture profiles of varying heating rates for multiple insulation techniques as well the strong influence of the addition of spallingmitigating additives is presented. The first ever example of neutron tomography of a spalled sample is also reported, and some preliminary analyses of the effect that moisture clog formation and heating rates have on it are revealed.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives

Tengattini

Pont

Sleiman

et al. 2020

Strain

Self Cite

View full text Add to dashboard Cite

show abstract

“…As the NM has been designed as self-contained detector that can be transported between the beamlines at PSI with only moderate effort, it can also be moved to other neutron sources. Because the neutron source of ILL provides outstanding neutron flux conditions, the NM detector system was transferred recently from PSI to the D50 beamline [15] at ILL and its performance under cutting edge flux conditions has been tested With an estimated neutron flux of 6 × 10 9 n/cm 2 s -1 , the D50 beamline provides currently the highest available flux of cold neutrons for imaging applications. In the following we provide some results of this initial campaign.…”

Section: Introductionmentioning

confidence: 99%

PSI ‘Neutron Microscope’ at ILL-D50 Beamline - First Results

Trtik

Meyer²,

Wehmann³

et al. 2020

Neutron Radiography - WCNR-11

View full text Add to dashboard Cite

A high-resolution neutron imaging system referred to as 'Neutron Microscope' (NM) has been recently established as a piece of instrumental equipment at the Paul Scherrer Institut (PSI), Switzerland. It is providing the wide user community of the Neutron Imaging and Applied Materials Group (NIAG) with the capability of spatial image resolution below 5 µm at effective pixel sizes of 1.3 µm. The NM has been designed as a portable, self-contained system that can be moved between beamlines at PSI with only moderate effort. In this contribution, we report on the first results and experience with the Neutron Microscope externally, at a beamline of another neutron source outside the Swiss Spallation Neutron Source (SINQ). In June 2018, NM has been transported to the Institute Laue-Langevin (ILL) and was successfully installed at the D50 beamline for four days. A gadolinium based Siemens star produced at PSI has been used for the assessment of the spatial resolution. The spatial resolution achieved using the Neutron Microscope at ILL-D50 equalled 4.5 µm. Above that, several high-resolution tomographies of various samples were acquired, of which an illustrative example is presented.

show abstract

“…Ref. [12] presents an excellent example of the interest of neutron tomography for concrete, where the loss of water during a simulated fire can easily be quantified. Furthermore, the isotope 2 sensitivity of neutrons allows flow paths to be measured in saturated conditions such as in Ref.…”

Section: Introductionmentioning

confidence: 99%

The colours of concrete as seen by X-rays and neutrons

Roubin

Andò

Roux

2019

Cement and Concrete Composites

View full text Add to dashboard Cite

Both x-ray tomography and neutron tomography give very detailed insight in the microstructure of concrete. However, their different contrasts, due to different compositional sensitivities, make one modality more relevant for some features. The present study shows that both types of images acquired on the same specimen may be registered onto each other, after the statistical joint distribution of absorption coefficients has been learned. A Gaussian mixture model has been used to identify up to five different phases having different signatures. A staggered algorithm consisting in i) adjusting the joint histogram to fit phases and their variances and ii) registering the two 3D images onto each other, within a multi-scale algorithm is presented in details. The analysed experimental data illustrates the benefit of using jointly both modalities as compared to their parallel usage.

show abstract

Analysis of moisture migration in concrete at high temperature through in-situ neutron tomography

Cited by 77 publications

References 26 publications

Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives

Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives

PSI ‘Neutron Microscope’ at ILL-D50 Beamline - First Results

The colours of concrete as seen by X-rays and neutrons

Contact Info

Product

Resources

About