Silica, ground-water compositions

Ground-water composition would be altered by the glass, either by two-phase chemical reactions or, more likely, by leaching of glass components. In particular, relatively high concentrations of dissolved and colloidal silica would be expected. 

Solubility calculations were added for two allophanes, for which the equilibrium constants and formulae are a function of pH. Paces (74) found cold ground waters collected from springs in granitic rocks of the Bohemian Massif of Czechoslovakia to be supersaturated with respect to kaolinite while being unsaturated with respect to amorphous silica. He interpreted this as an indication that a metastable aluminosilicate more soluble than kaolinite was controlling the concentrations of alumina and silica in these waters. This aluminosilicate was further hypothesized to be of varied chemical composition, controlled by the mole... 

Composite cements may contain mineral additions other than, or as well as, ones with pozzolanic or latent hydraulic properties. Regourd (R34) reviewed the use of ground limestone, which is widely used in France in proportions of up to 27%. The limestones used consist substantially of calcite, with smaller proportions of quartz or amorphous silica and sometimes of dolomite. They must be low in clay minerals and organic matter because of the effects these have on water demand and setting, respectively. The XRD peaks of the calcite are somewhat broadened, indicating either small crystallite size or disorder or both IR spectra confirm the occurrence of disorder. 

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