Keywords and Phrases
Cement Chemistry; Filler Effect; Hydration Kinetics; Machine Learning; Pozzolanic Effect; Thermodynamics
” This research is made up of several studies. The first study focused on understanding the reaction kinetics of Ca3SiO5 and metakaolin (MK) mixtures compared to Ca3SiO5 and silica fume (SF) mixtures. It was shown that MK was a more effective additive than SF at small replacement levels (i.e. ≥ 10% by mass) while higher replacement levels of MK became a detriment due to excess (Al(OH)4¯) ions preventing the nucleation and growth of C-S-H. In a follow-up study where the MK particle size distribution (PSD) was modified, similar effects were observed but unlike typical mineral additives (e.g. limestone), it was the coarse PSD that was optimal. A different study examined the contradiction between experimental data and classical phase boundary nucleation and growth (pBNG) models as the water to cement content (w/c) increases. When the reaction rates were measured via isothermal calorimetry, they were insensitive to changes in w/c whereas increasing w/c affected simulated reaction rates. Utilizing a modified pBNG model, these contradictions were rectified by accounting for physical phenomena. It was demonstrated that hybrid random forest firefly algorithm (RF-FFA) is highly effective at predicting compressive strength of concrete with the mix design as an input. The subsequent study, [Ca3Al2O6 + CaSO4] mixtures were hydrated in solutions of varying water activity (aH), the solubility product of Ca3Al2O6 and the critical aH to arrest hydration were determined as 10-20.65 and 0.45 for the first time. In the final study, high α-Al2O3 calcium aluminate cements mixtures were hydrated with limestone or calcium sulfate. While the binary mixtures exhibited an increase in the heat released, this did not translate to greater the compressive strengths”--Abstract, page v.
Brow, Richard K.
O'Malley, Ronald J.
Smith, Jeffrey D.
Materials Science and Engineering
Ph. D. in Materials Science and Engineering
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Influence of Pozzolanic Additives on Hydration Mechanisms of Tricalcium Silicate
- Elucidating the Effect of Water-To-Cement Ratio on the Hydration Mechanisms of Cement
- Effect of Particle Size Distribution of Metakaolin on Hydration Kinetics of Tricalcium Silicate
- Prediction of Compressive Strength of Concrete: Critical Comparison of Performance of a Hybrid Machine Learning Model with Standalone Models
- Influence of Water Activity on Hydration of Tricalcium Aluminate Calcium Sulfate Systems
- Hydration of High-Alumina Calcium Aluminate Cements with Carbonate and Sulfate Additives
xx, 317 pages
© 2020 Jonathan Lee Lapeyre, All rights reserved.
Dissertation - Open Access
Lapeyre, Jonathan, "Thermodynamic investigations of pure and blended cement mixtures" (2020). Doctoral Dissertations. 2954.