Influence of acrylic superplasticizer and cellulose-ether on the kinetics of tricalcium silicate hydration reaction

This paper reports on the analysis of the hydration kinetics of a tricalcium silicate paste cured in presence of polymers industrially used in the extrusion process of mortars. In particular, we investigated the effect of a rheology-modifying additive (a methyl hydroxy ethyl cellulose) and a superplasticizer (a polyacrylic polymer). These polymers have been added to tricalcium silicate paste, both separately and together, to understand their distinct influence on the tricalcium silicate hydration and their possible synergies. The kinetic curves have been monitored from 10 to 40 °C by means of Differential Scanning Calorimetry and fitted using the generalized Boundary Nucleation and Growth Model combined to a diffusion-limited model, to extract: induction times, reaction rates, activation energies and diffusion coefficients. As a main result, this paper contributes to the advancement of the knowledge in the field of the extrusion process of cementitious materials, providing a thermodynamic support to the empirical evaluations of the additives performances.

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► We studied the hydration kinetics of tricalcium silicate cured with additives.
► The investigated additives are commonly used in the industry for extrusion.
► The kinetics obtained by means of DSC were fitted to extract the kinetic parameters.
► Polymers reduce the nucleation rate and increase the growth rate of the hydrates.
► Polymers reduce the dependence of the diffusion coefficient on the temperature.