Radiological behaviour of pigments and water repellents in cement-based mortars

Suárez-Navarro, J. A.; Lanzón, Marcos; Moreno-Reyes, A. M.; Gascó, C.; Alonso, M.M.; Blanco-Varela, María Teresa; Puertas, Francisca

doi:10.1016/j.conbuildmat.2019.07.271

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…The HJ-Biplot graph demonstrated that the sludges had a higher concentration of Fe 2 O 3 (Figures 3 and 4). This suggests that the increased presence of uranium series radionuclides may be due to an association with iron compounds, as observed in other matrix types [15,16,30]. The 40 K activity concentrations were also consistent with other studies, ranging from 136 Bq kg −1 to 497 Bq kg −1 [4,8].…”

Section: Discussionsupporting

confidence: 90%

See 1 more Smart Citation

An Evaluation of the Radioactive Content of Ashes Obtained from the Use of Fuels from Recycled Materials by Co-Processing in the Cement Industry

Suarez-Navarro,

Sanjuán,

Mora

et al. 2024

Materials

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The co-processing of different wastes as fuels in the manufacture of cement clinker not only meets the objectives of a circular economy but also contributes to the reduction in CO2 emissions in the manufacture of Portland cement. However, waste used as alternative fuels, such as sludge or organic-rich residues, may contain naturally occurring radionuclides that can be concentrated during the combustion process. In this study, the presence of natural radionuclides (radioactive series of uranium, thorium, and 40K) and anthropogenic radionuclides (137Cs) in these wastes has been investigated by gamma spectrometry. Possible relationships between the radioactive content and the obtained chemical composition, determined by X-ray fluorescence, have also been studied by applying a principal component analysis (PCA). The results showed that the wastes with the highest radioactive content were sewage sludge with activity concentrations of 238U and 210Pb of 321 ± 38 Bq kg−1 and 110 ± 14 Bq kg−1, respectively. A correlation between radioactive content and Fe2O3 concentration was also observed. The annual effective dose rates to workers for the ashes estimated from the ash content ranged from 0.0033 mSv to 0.092 mSv and therefore do not pose a risk to workers as they are lower than the 1 mSv per year limit for the general public (DIRECTIVE 2013/59/EURATOM).

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Section: Discussionsupporting

confidence: 90%

“…The doses from the final waste ash were assessed following the criteria set out in Radiation Protection 122 [29]. The doses were determined for the 'small heap' scenario for workers, where the total annual dose rate (E A , µSv y −1 ) is given by expression (3) [30].…”

Section: Assessment Of the Effective Doses Of The Residues Used For W...mentioning

confidence: 99%

An Evaluation of the Radioactive Content of Ashes Obtained from the Use of Fuels from Recycled Materials by Co-Processing in the Cement Industry

Suarez-Navarro,

Sanjuán,

Mora

et al. 2024

Materials

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“…The Activity Concentration Index (ACI) is a screening value, introduced in European Directive EURATOM 2013/59 [ 1 ], used to determine the suitability of building materials from the point of view of radiological protection [ 2 , 3 , 4 ]. It is determined by the following expression (1):

where

, and

are the activity concentrations of 226 Ra, 232 Th, and 40 K. For the building material to comply with this Directive, the ACI value must be ≤1 mSv y −1 , not taking into account the environmental background.…”

Section: Introductionmentioning

confidence: 99%

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

et al. 2023

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The manufacture of Portland cement entails high energy and environmental costs, and various solutions have been implemented in recent years to mitigate this negative impact. These solutions include improvements in the manufacture of cement clinker or the use of supplementary cementitious materials (SCMs), such as fly ash (FA) or slag as a replacement for a portion of the clinker in cement. The incorporation of these SCMs in cement may increase its radiological content as they are naturally occurring radioactive materials (NORMs). The Activity Concentration Index (ACI) is a screening tool established in the European EURATOM Directive 2013/59 to determine the radiation protection suitability of a final construction material. The ACI is determined by the activity concentrations of 226Ra, 232Th and 40K, usually determined by gamma spectrometry. The methodology of gamma spectrometry is accurate and appropriate, but this technique is not available in all laboratories. For this reason, and taking into account that there is a relationship between the chemical and radiological composition of these building materials, a new approach is proposed to determine the radiological content of these materials from a chemical analysis such as X-ray fluorescence (XRF). In this paper, principal component analysis (PCA) is used to establish the relationships between the chemical composition and radiological content of cements, FAs, and slags of different natures. Through PCA it was possible to group the cements based on two variables: CaO content and Fe2O3–Al2O3–TiO2 content. A lower correlation was observed for the FAs and slags, as the sample scores were centered around the origin of the coordinates and showed greater dispersion than the cements. The clusters obtained in the HJ–Biplots allowed the determination, using multiple regression, of models relating the activity concentration of 226Ra, 232Th (212Pb), and 40K to the oxide percentages obtained for the three matrices studied. The models were validated using five cements, one FA and one slag with relative percentage deviations (RSD(%)) equal to or less than 30% for 89% of the activity concentrations and 100% of the ACI determined.

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“…Organic and inorganic admixtures (natural or artificial pigments) are also widely used in concrete manufacture. Some natural pigments may also have a high radioactive (48).…”

Section: Norm Waste Used In Cement and Concrete Productionmentioning

confidence: 99%

“…Very few studies have been conducted on the contribution of concrete admixtures to overall concrete radiological behaviour. The authors of this article, under project BIA2016-77252-R, explored the behaviour of several organic and inorganic admixtures used as pigments or water repellents in concretes and mortars (48). Low radionuclide concentrations were observed except in natural pigments, which raised the 238 U series concentration.…”

Section: Portland Cements and Concretesmentioning

confidence: 99%

NORM waste, cements, and concretes. A review

Puertas

Suárez-Navarro²,

Alonso

et al. 2021

materconstrucc

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The use of industrial waste and/or by-products as alternative sources of raw materials in building materials has become standard practice. The result, more sustainable construction, is contributing to the institution of a circular economy. Nonetheless, all necessary precautions must be taken to ensure that the inclusion and use of such materials entail no new health hazard for people or their environment. Due to the processes involved in generating industrial waste/by-products, these alternative or secondary materials may be contaminated with heavy metals, other undesirable chemicals or high levels of natural radioactivity that may constrain their use. In-depth and realistic research on such industrial waste is consequently requisite to its deployment in building materials. This paper reviews the basic concepts associated with radioactivity and natural radioactivity, focusing on industrial waste/by-products comprising Naturally Occurring Radioactive Materials (NORM) used in cement and concrete manufacture. Updated radiological data are furnished on such waste (including plant fly ash, iron and steel mill slag, bauxite and phosphogypsum waste) and on other materials such as limestone, gypsum and so on. The paper also presents recent findings on radionuclide activity concentrations in Portland cements and concretes not bearing NORMs. The role of natural aggregate in end concrete radiological behaviour is broached. The radiological behaviour of alternative non-portland cements and concretes, such as alkali-activated materials and geopolymers, is also addressed.

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Radiological behaviour of pigments and water repellents in cement-based mortars

Cited by 9 publications

References 39 publications

An Evaluation of the Radioactive Content of Ashes Obtained from the Use of Fuels from Recycled Materials by Co-Processing in the Cement Industry

An Evaluation of the Radioactive Content of Ashes Obtained from the Use of Fuels from Recycled Materials by Co-Processing in the Cement Industry

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

NORM waste, cements, and concretes. A review

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