Using micro X-ray fluorescence to image chloride profiles in concrete

Moradllo, Mehdi Khanzadeh; Sudbrink, Bryan; Hu, Qinang; Aboustait, Mohammed; Tabb, Braden; Ley, M. Tyler; Davis, Jeffrey M.

doi:10.1016/j.cemconres.2016.11.014

Cited by 49 publications

(13 citation statements)

References 14 publications

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“…Table 4 summarizes the settings used by the µXRF in this work. More details can be found in other publications [25][26]. 2.6 TXM Data Analysis First, the radiographs of the air were subtracted from sample scans to remove the background attenuation effects.…”

Section: Comparing CL and I Penetration Using µXrfmentioning

confidence: 99%

“…The penetration of Cl and I in paste samples was also determined gravimetrically and with micro X-ray fluorescence (µXRF) at these same conditions and then compared with the TXM results. µXRF provides individual compositional maps which can be combined into a single map that simultaneously provides unique compositions and location [25][26][27][28][29]. Furthermore, µXRF imaging was used to compare I and Cl penetration concentration profiles in paste samples.…”

Section: Introductionmentioning

confidence: 99%

“…The average I and Cl counts in each layer can then be plotted for different depths.Next, the calibration curves are used to convert I and Cl counts to concentrations. Additional details can be found in previous publications[25][26].…”

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confidence: 99%

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Quantitative measurement of the influence of degree of saturation on ion penetration in cement paste by using X-ray imaging

Moradllo

Ley

2017

Construction and Building Materials

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The external penetration of ions into concrete plays an important role in long-term durability of concrete structures. In addition, the degree of saturation (DoS) of the paste has a large impact on rate and mechanisms of fluid penetration into concrete. There is little knowledge of the dynamic process of fluid penetration into these materials because few experimental techniques are able to give quantitative spatial measurements of the fluid movement without damaging the sample. This paper uses laboratory transmission X-ray microscopy (TXM) to investigate the in-situ penetration of an iodide based tracer into cement paste with water-to-cement ratio of 0.40 conditioned at four different relative humidities (RH). This technique can non-destructively image the distribution of the dissolved ions at 8.8 m resolution in minutes. In addition, micro X-ray fluorescence (µXRF) imaging and conventional gravimetric measurements were used to compare I and Cl penetration rate and validate the results from TXM. Mathematical models have been proposed to account for ion penetration in partially-saturated samples. The results show that samples that were ponded for two days after being conditioned in 35% and 70% RHs (DoS of 40.8% (± 0.1%) and 68.8% (± 0.5%) respectively) show a 40x and 10x increase respectively in the penetration coefficient over the saturated sample. Furthermore, important insights about combined ion transport mechanisms have been observed from concentration profiles by TXM.

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Section: Comparing CL and I Penetration Using µXrfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantitative measurement of the influence of degree of saturation on ion penetration in cement paste by using X-ray imaging

Moradllo

Ley

2017

Construction and Building Materials

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“…Another promising method is X-ray fluorescence (XRF) [19]. For its application in the field of concrete, see e.g., [20]. The use of this technique offered spatial resolved chloride distributions and quantified ingress profiles regarding to the cement [21].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Modeling of Chloride Penetration with Respect to Concrete Heterogeneity and Epoxy-Coating on the Reinforcement

Lehner

Konečný

2019

Materials

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The presented article demonstrates the probabilistic method based modeling of the 2D chloride ingress into reinforced concrete structures with respect to concrete heterogeneity and epoxy-coated steel reinforcement. Spatial change of concrete diffusion is assessed through the investigation of random variation of the ability of concrete to resist chloride ingress. Time-dependent chloride concentration at the reinforcement level in both homogeneous and heterogeneous models is comparatively considered taking into account of the influence of reinforcement protection as well as the defects and holidays of the coating. Expansion optimal linear estimation method is exploited to generate a random field for the structure at the mesoscale and correlation length is employed to simplify the modeling process. Preliminary analyses of the built model are conducted in both deterministic and probabilistic solutions under the scheme of the finite element method. Thus, possibility of such analyses is exploited.

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“…Although the corrosion evolution can be predicted by calculations, the current models for service life prediction are not sufficient to provide reliable prevention and monitoring. 17 Besides spectroscopic techniques (e.g., optical fibers, 18 X-ray analysis, 19 low-frequency electromagnetic waves 20 ), traditional Ag/AgCl ion-selective electrodes (ISEs) for chloride determination have been used for this purpose since the 1990s. 17,21−23 The working principle for chlorides on the solid matrix of concrete is analogous to the chloride detection in solution; the dissolution/precipitation of Ag + occurs at the Ag/AgCl electrode upon the variation of chlorides concentration, according to the solubility product constant, thus resulting in changes of the ISE potential that are monitored by potentiometry.…”

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confidence: 99%

Vertical-Flow Paper Sensor for On-Site and Prompt Evaluation of Chloride Contamination in Concrete Structures

et al. 2021

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Corrosion occurring in reinforced concrete has turned into a primary concern of the current century, concrete being the most ubiquitous and predominant material used in the construction industry. Among the many interrelated processes that trigger corrosion of metallic reinforcements, the penetration of chloride ions into the concrete matrix is the most insidious threat. Herein, we developed the first electrochemical device entirely made of paper that allows for the direct, prompt, and noninvasive evaluation of free chloride ion contamination in concrete-based constructions. Our device is based on a three-layer wax-modified filter paper, consisting of two Ag/AgCl screen-printed electrodes that are interfaced by a junction pad in a sandwich-like configuration. Filter paper allows for generating a vertical-flow potentiometric device capable of measuring the electrochemical potential between two solutions containing different concentrations of chloride ions, which are separately drop-cast on the top and bottom layers. After demonstrating the analytical performance of the device, the same principle was applied to the evaluation of the chloride contents in different concrete samples, exploiting paper as a suitable interfacing material for potentiometric measurements on the cement solid surface. Laboratory-prepared concrete samples with known chloride contents were first assessed, and then, the paper-based verticalflow device was applied to real concrete structures at the Giacomo ManzùMuseum (Ardea, Italy) for the evaluation of chloride contamination caused by the proximity to the seaside. The capability of our device to provide timely warning of the risk conditions of concrete-based artifacts was demonstrated.

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Using micro X-ray fluorescence to image chloride profiles in concrete

Cited by 49 publications

References 14 publications

Quantitative measurement of the influence of degree of saturation on ion penetration in cement paste by using X-ray imaging

Quantitative measurement of the influence of degree of saturation on ion penetration in cement paste by using X-ray imaging

Probabilistic Modeling of Chloride Penetration with Respect to Concrete Heterogeneity and Epoxy-Coating on the Reinforcement

Vertical-Flow Paper Sensor for On-Site and Prompt Evaluation of Chloride Contamination in Concrete Structures

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