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Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior
Ana María Moreno de Los Reyes1, José Antonio Suárez-Navarro2, María Del Mar Alonso1
1Department of Materials, Eduardo Torroja Institute for Construction Sciences (IETcc-CSIC), 28033 Madrid, Spain.
Molecules (Basel, Switzerland)
|January 21, 2022
Summary
This study validates a new method for measuring radioactivity in eco-efficient cements. The method confirmed that cement composition variables do not affect radioactive content in solid samples.
Area of Science:
- Construction Materials Science
- Environmental Science
- Nuclear Chemistry
Background:
- Sustainable construction relies on eco-efficient cements, often incorporating industrial by-products.
- These by-products can contain naturally occurring radioactive materials (NORMs), posing potential radiological risks.
- Accurate assessment of radionuclide activity is crucial for evaluating the safety of these sustainable materials.
Purpose of the Study:
- To introduce and validate a novel gamma spectrometric method for radionuclide activity measurement in solid cement specimens.
- To investigate the influence of alkaline activation variables (activator type, reaction time, curing conditions) on the microstructure and radiological behavior of hybrid cements.
- To compare radioactivity measurements from solid specimens versus powder samples.
Main Methods:
- Development and application of a gamma spectrometric technique for analyzing 5 cm cubic solid specimens of hybrid alkali-activated cements.
- Microstructural analysis of cement pastes to correlate with observed radiological properties.
- Comparative analysis of radionuclide activity in solid samples versus powder samples.
Main Results:
- The new gamma spectrometric method for solid specimens was validated as reliable.
- Microstructural analysis revealed similar reaction products (C-S-H, C-A-S-H, (N,C)-A-S-H) across different activation conditions, but with varying microstructures.
- Crucially, variables in hybrid cement activation did not impact the radioactive content of solid specimens.
- Powder samples exhibited radon-222 (radon-222) emanation, potentially linked to fly ash structural changes during activation.
Conclusions:
- The developed gamma spectrometry method is effective for assessing radioactivity in solid eco-efficient cement specimens.
- Activation process variables do not alter the inherent radionuclide content of the solid cement matrix.
- Further investigation is needed to understand the radon-222 (radon-222) emanation observed in powder samples and its implications.
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