Relating early hydration, specific surface and flow loss of cement pastes
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Flow loss in superplasticized systems has been mainly explained in qualitative and comparative ways over the past years. This is due to the intrinsic complexity of the underlying mechanism involving a change in the agglomeration degree as a result of cement hydration. The lack of robust and reliable experimental methodologies must have additionally discouraged researchers from attempting to understand the phenomena of flow loss in quantitative terms. Thanks to new analytical methods, it was possible to prove that after the so-called onset point, yield stress increases exponentially with the increase of both heat rate measured by isothermal calorimetry and specific surface. This paper also identifies the existence of a direct proportionality between the increase of heat rate and the increase of specific surface area during the acceleration period, most likely reflecting the nucleation and growth nature at this stage of the cement hydration.
KeywordsSuperplasticizers Yield stress Heat rate Isothermal calorimetry BET model
Funding for Sara Mantellato was provided by the SNSF Project (No. 140615) titled “Mastering flow loss of cementitious systems” and the SNSF National Centre for Competence in Research in Digital Fabrication—Innovative Building Processes in Architecture. The authors wish to thank Lukas Frunz (SIKA AG Schweiz) for providing the polymers and Giulia Gelardi (ETH Zürich) for their characterization.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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