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. 2022 Jan 13;27(2):498.
doi: 10.3390/molecules27020498.

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

Ana María Moreno de Los Reyes  1 , José Antonio Suárez-Navarro  2 , María Del Mar Alonso  1 , Catalina Gascó  2 , Isabel Sobrados  3 , Francisca Puertas  1
Affiliations

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

Ana María Moreno de Los Reyes et al. Molecules. .

Abstract

The use of more eco-efficient cements in concretes is one of the keys to ensuring construction industry sustainability. Such eco-efficient binders often contain large but variable proportions of industrial waste or by-products in their composition, many of which may be naturally occurring radioactive materials (NORMs). This study explored the application of a new gamma spectrometric method for measuring radionuclide activity in hybrid alkali-activated cements from solid 5 cm cubic specimens rather than powder samples. The research involved assessing the effect of significant variables such as the nature of the alkaline activator, reaction time and curing conditions to relate the microstructures identified to the radiological behavior observed. The findings showed that varying the inputs generated pastes with similar reaction products (C-S-H, C-A-S-H and (N,C)-A-S-H) but different microstructures. The new gamma spectrometric method for measuring radioactivity in solid 5 cm cubic specimens in alkaline pastes was found to be valid. The variables involved in hybrid cement activation were shown to have no impact on specimen radioactive content. The powder samples, however, emanated 222Rn (a descendent of 226Ra), possibly due to the deformation taking place in fly ash structure during alkaline activation. Further research would be required to explain that finding.

Keywords: NORMs; alkaline activation; characterization; fly ash; gamma spectrometry and radon; hybrid cements.

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Conflict of interest statement

The authors declare that they have no known competing financial interest or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
OPC and FA particle size distribution.
Figure 2
Figure 2
Flowchart for procedure followed and variables used to prepare hybrid cement paste specimens.
Figure 3
Figure 3
Ca-Si-Al ternary diagrams for (A) 2 days and (B) 28 days of HN T25, HN T80, H-WG T25 and H-WG T80 pastes.
See this image and copyright information in PMC

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