Dynamics of concentrated white portland cement suspensions using multispeckle diffusing wave spectroscopy

• Published in: Construction & building materials Vol. 323; p. 126407
• Main Authors: Ojeda-Farías, O., Hébraud, P., Lootens, D., Liard, M., Durán-Herrera, A., Mendoza-Rangel, J.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 14.03.2022; Elsevier
• Subjects: Autocorrelation function; Cement suspensions; Chemical Sciences; Dynamics; Material chemistry; Multispeckle diffusing wave spectroscopy; Rheology; Autocorrelation function; Cement suspensions; Multispeckle diffusing wave spectroscopy; Dynamics; Rheology
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2022.126407

[Display omitted] •The application of multispeckle diffusing wave spectroscopy (MSDWS) to white portland cement suspensions has been studied.•The dynamics of concentrated white portland cement suspensions were discussed.•Stretched exponential decay to study the dynamics of white portland cement suspensions has been proposed. Cement suspensions behave as a complex fluid from the rheological point of view as they are non-Newtonian fluids and their rheology is time dependent. The early-age hydration kinetics is mainly studied because of the importance of the determination of the initial and final setting time for all the applications of the cementitious materials. The particles within the fresh cement suspension are subject to several interactions which tend to cause aggregation of particles. The dynamics of the systems play an important role in the evolution of the size, density, and mechanical strength of these aggregates over time, and consequently control the macroscopic behavior. In this paper, the dynamics of several white portland cement suspensions with water to cement ratios from 0.25 to 0.46 have been studied. The motion of cement particles was characterized via multispeckle diffusing wave spectroscopy (MSDWS) in back scattering geometry, and the dynamics were described in terms of an autocorrelation function data. At all water to cement ratios, the dynamics of the particles slows down as a function of time. But at intermediate water to cement ratios, the consolidation of the particles networks occurs through temporally heterogeneous rearrangements of the particles. Such rearrangements do not occur at higher water to cement ratios. This behavior is correlated with a loss of flexural rigidity of the set cement.