Authors:W.Y. Gao, Y.W. Wang, L.M. Dong, and Z.W. Yu1
A microcalorimeter (Setaram c-80) was used
to study the thermokinetics of the hydration process of calcium phosphate
cement (CPC), a biocompatible biomaterial used in bone repair. The hydration
enthalpy was determined to be 35.8 J g–1
at 37.0°C when up to 80 mg CPC was dissolved in 2 mL of citric buffer.
In the present study, parameters related to time constants of the calorimeter
were obtained by fitting the recorded thermal curves with the function θ=Ae–?t(1– e–?2t).
The real thermogenetic curves were then retrieved with Tian function and the
transformation rate of the hydration process of CPC was found to follow the
The microstructures of the hydrated CPC were examined by scanning electron
microscopy. The nano-scale flake microstructures are due to crystallization
of calcium phosphate and they could contribute to the good biocompatibility
and high bioactivity.
particles in the first few minutes, while free water mainly contributes to fluidity of cement paste.
Since cement paste were mixed, the structure of cement paste is formed and becomes denser as hydration proceeds. If the hydrationprocess of cement
Differential calorimetry was used to determine the heat evolution and kinetics of hydration processes of the calciumsulphatealuminate phase Ca4(Al6O12)(SO4) with gypsum CaSO4 · 2H2O at room temperature with one mole of water added to the solid phase. An increasing content of sulphate ions in the sytem results in substitution of the monosulphate Ca4(Al2O6)(SO4) · 12H2O in the reaction products by ettringite, Ca6(Al2O6)(SO4)3 · 32H2O. Higher contents of ettringite influence the rates of hydration reactions and the values of the evolved heat.
Influence of the additives and admixtures on portland cement hydration
The main components of OPC are tricalciumsilicate (3CaO·SiO 2 , C 3 S, alite), dicalciumsilicate (2CaO·SiO 2 , C 2 S belite), tricalcium
Authors:Valentin Antonovič, Marius Aleknevičius, Jadvyga Kerienė, Ina Pundienė, and Rimvydas Stonys
physical properties in the hardened state. The authors of [ 22 ] have found that, depending on the chemical structure, polycarboxylate ethers influence the hydrationprocess of CAC. They can either retard or accelerate cement hydration, which can result
calcium silicate hydrates formed at C 3 S and C 2 S hydrations, a corresponding excess of Ca(OH) 2 (portlandite) results [ 11 ].
Monitoring the evolution in time of the hydrationprocess by the proportion of calcium silicate hydrates is rather
Authors:Alina Bădănoiu, Jenica Paceagiu, and Georgeta Voicu
good mineralizer for Portland cement production [ 11 , 12 ], but little information is available regarding its influence on the hydrationprocesses of resulted clinker and cement [ 13 ]. Due to the simultaneous presence of fluorides and Cu/Sn elements
composition of the hydrates. Nonetheless, results of OPC and blended cements can be compared to detect the differences in hydrationprocess between both.
In this research, isothermal calorimetric measurements and TG analyses were performed on pastes in
Authors:Alex Neves Junior, Romildo Dias Toledo Filho, Eduardo de Moraes Rego Fairbairn, and Jo Dweck
post-accelerating cement hydration stages, the available free water controls the hydrationprocess and there is a higher formation of hydrated products. Thus, the paste prepared with W/C = 0.55 presents more hydrated products and total combined water