High Hydration Activity Research Articles

The Experimental Studies on the Prepartion of Steel Slag Cement by Gas Quenching Steel Slag

According to a series of experimental studies such as the content of the f-CaO, the relative grindability index of the gas quenching steel slag, the properties of gas quenching steel slag cement and a detailed analysis of the potential economic benefits of steel slag cement. It was found that it has a huge economic benefits in preparing the cement with gas quenching steel slag.The results showed that the content of f-CaO in slag particles less than 2mm were no more than 2.7% and there exists a well proportional relation between it and the grain size; the grindability of gas quenching steel slag is much better than heat-stew steel slag; what's more,because of the high hydration activity of gas quenching steel slag, it can be produced the perfect steel slag cement with excellent hydration, stability and strength.

Highly Reactive Remelted Belite

Remelted belite showed higher hydration activity and better grindability than the quenched material. Both properties were closely related to the belite microtextures induced by the remelting reaction; after the reaction, the belite showed disintegration of the intracrystalline lamella structure, inclusion of the liquid exsolved on the former lamella boundaries, and crystallization of the liquid during further cooling. The fractures easily penetrated the remelted crystal grains upon grinding, probably along the disintegrated lamella boundaries and/or along the inclusions. The resulting fragments were irregular in shape with high specific surface area, leading to the high hydration activity of the remelted belite.

The structure and quantum chemistry studies of 3CaO · 3Al 2O 3 · SrSO 4

The 3CaO · 3Al 2O 3 · SrSO 4 single crystals are prepared and defined with PbCl 2 as a flux. By means of structure analyzing the overall crystal parameters are obtained. The space group is I4̄3m, and unit cell parameter is a = 9.210(4)Å. Atomic coordinates, bond lengths and angles are refined. By a SCC-DV-X α method of quantum chemistry the molecular structures of 3CaO · 3A1 2O 3 · SrSO 4 and 3CaO · 3Al 2O 3 · BaSO 4 are discussed in detail. The Fermi energy, bond order, population, net charge and covalent bond order of molecular structures are obtained. Possessing higher net charge of Ba atoms, lower atomic bond order and covalent bond order of Ba and Ba-O bond than those of Sr and SrO bond in 3CaO · 3A1 2O 3 · SrSO 4, 3CaO · 3A1 2O 3 · BaSO 4 has higher hydration activity and initial rate of hydration.

Characterization of C‐S‐H from Highly Reactive β‐Dicalcium Silicate Prepared from Hillebrandite

β‐dicalcium silicate synthesized by thermal dissociation of hydrothermally prepared hillebrandite (Ca2(SiO3)(OH)2) exhibits extremely high hydration activity. Characterization of the hydrates obtained and investigation of the hydration mechanism was carried out with the aid of trimethylsilylation analysis, 29Si magic angle spinning nuclear magnetic resonance, transmission electron microscopy selected area electron diffraction, and XRD. The silicate anion structure of C‐S‐H consisted mainly of a dimer and a single‐chain polymer. Polymerization advances with increasing curing temperature and curing time. The C‐S‐H has an oriented fibrous structure and exhibits a 0.73‐nm dreierketten in the longitudinal direction. On heating, the C‐S‐H dissociates to form β‐C2S. The temperature at which βC2S begins to form decreases with increasing chain length of the C‐S‐H or as the Ca/Si ratio becomes higher. The high activity of β‐C2S is due to its large specific surface area and the fact that the hydration is chemical‐reaction‐rate‐controlled until its completion. As a result, the hydration progresses in situ and C‐S‐H with a high Ca/Si ratio is formed.