Abstract: The early-age hydration of cement is inhibited in the presence of comb-shaped polycarboxylate ether (PCE) polymer -- a dispersant commonly added to control rheological properties of fresh cement paste. This study employs a series of microcalorimetry experiments and phase boundary nucleation and growth simulations to elucidate the effects of dosage and molecular architecture of PCE on hydration of tricalcium silicate (Ca3SiO5 or C3S in cement notation), the dominant phase in cement. Results show that PCE -- regardless of its molecular architecture -- suppresses early-age hydration of C3S. PCE-induced retardation becomes increasingly more pronounced as dosage of PCE in the paste increases. Such suppression of C3S hydration has been attributed to adsorption of PCE molecules on silicate surfaces, which inhibit topographical sites of C3S dissolution and C–S–H nucleation, and impede the post-nucleation growth of C–S–H. This study develops a correlation between molecular architecture of PCE and its ability to suppress C3S hydration through quantitative analyses of retardation effects induced by PCEs with different molecular architectures. The numerical equation, describing such correlation, offers a reliable, and, more importantly, a readily quantifiable indicator of PCE’s potential to suppress C3S hydration in relation to its dosage and molecular architecture. In the context of practical application of this study, the aforementioned numerical equation can be used to order and rank PCEs -- of various molecular architectures -- on the bases of their potentials to suppress C3S hydration, and to select ones that cause the optimum (i.e., user-desired) extent of hydration suppression.


Civil, Architectural and Environmental Engineering

Second Department

Materials Science and Engineering


Funding for this research was provided by the University of Missouri Research Board [UMRB], and the National Science Foundation [NSF, CMMI: 1661609]. Experimental and computational tasks were conducted in the Materials Research Center and Department of Materials Science and Engineering at Missouri S&T. The authors gratefully acknowledge the financial support that has made these laboratories and their operations possible.

Keywords and Phrases

C S 3; Hydration kinetics; Microcalorimetry; Nucleation and growth; PCE; Simulation

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Article - Journal

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Final Version

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Publication Date

03 Feb 2019