Dear Colleague,

Your intention to conduct thermodynamic modeling of cement hydration processes utilizing X-ray fluorescence (XRF) analysis results is scientifically justified and relevant.

Allow me to propose several recommendations for implementing this approach:

1. Selection of Thermodynamic Model and Software: The most recognized and widely utilized software packages in scientific practice are those based on Gibbs energy minimization methods (e.g., GEMS, CemGEMS, PHREEQC with the CEMDATA thermodynamic database). These tools accurately describe the phase composition of cement systems under equilibrium conditions.

2. Preparation of Initial Data: XRF analysis results should initially be converted into molar oxide ratios. It is crucial to account for loss on ignition (LOI), as it significantly influences the accuracy of subsequent calculations.

3. Characteristics of Thermodynamic Modeling: It is important to note that thermodynamic models describe the equilibrium state of the system and do not directly account for kinetic aspects. To approximate actual conditions characteristic of the 28th day of hydration, it is advisable to specify the degree of hydration of clinker minerals empirically or experimentally determined.

4. Interpretation of Results: The modeling results can provide quantitative estimations of primary phases (C–S–H, portlandite, ettringite, monosulfoaluminate) and residual quantities of unhydrated clinker minerals. This enables a more comprehensive evaluation of the properties and durability of cement paste at the defined stage of its formation.

Дмитро Родіонов Thank you for the explanation. I have one more quick question. What if I want to incorporate the plasticizer effect in the cement hydration?

Thank you for your explanation. Including the effect of a plasticizer in cement hydration modeling is possible by adjusting the kinetic parameters within the utilized models (such as CEMHYD3D or similar). Typically, this is implemented by reducing the effective water-to-cement ratio, altering the hydration kinetics (slowing or accelerating specific phases), and modifying the morphology of hydration products. For a more accurate simulation, specifying the type and dosage of the plasticizer, as well as selecting or adapting the appropriate kinetic model, is essential.

Thank you for getting back to me. I want to start learning CEMHYD3D software for incorporating plasticizer in hydration. Where should I start? What is the most effective way to learn this process?

I am unable to access the program through the older NIST FTP links, as they are no longer functional. May I kindly request your guidance on: The current way to obtain or access the CEMHYD3D software package (v3.0).

Your support will be invaluable to help me move forward with the simulation component of my PhD research. Pawan Acharya

Дмитро Родіонов