Quasielastic Neutron Scattering Study of the Effect of Water-to-Cement Ratio on the Hydration Kinetics of Tricalcium Silicate

• Published in: Cement and concrete research Vol. 28; no. 2; pp. 231 - 243
• Main Authors: Berliner, R., Popovici, M., Herwig, K.W., Berliner, M., Jennings, H.M., Thomas, J.J.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Ltd 01.02.1998; Elsevier Science
• Subjects: Applied sciences; Buildings. Public works; Cement concrete constituents; Cements; Exact sciences and technology; Hydration; Materials; Properties of anhydrous and hydrated cement, test methods; Water cement ratio; Particle size distribution; Neutron scattering; Hydration; Cements; Kinetics; Experimental study; Energy transfer; C3S phase
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/S0008-8846(97)00260-3

Quasielastic neutron scattering (QNS) measurements of the hydration kinetics of tricalcium silicate (C 3S) have been made with 60 μeV energy resolution at a momentum transfer q = 1 Å −1. Monitoring the fraction of neutrons elastically scattered from C 3S paste specimens follows the progress of the C 3S hydration reactions. Three different water/cement ratios (w/c = 0.3, 0.5, and 0.7) were studied in this experiment. Analysis of the rate of reaction over the first approximately 15 h was by an Avrami model. After this time, the rate of hydration no longer follows nucleation and growth kinetics but enters a diffusion controlled regime. At this point, the rate of hydration depends strongly on the w/c, with more reaction at higher w/c ratios. A shrinking core model was used to analyze the diffusion-limited portion of the reaction at later times. The values of the apparent diffusion constant obtained from these data indicate a log-linear relationship between the diffusion constants and the w/c ratio.