Dietmar klammer8/2/2023 ![]() Therefore we investigated concrete samples from Austrian tunnels that show partially dissolved dolomite aggregates. In this study we are trying to gain new insides about the conditions that can lead to the dissolution of dolomite in concrete. Due to very low solubility of dolomite in alkaline solutions this reaction seems doubtful. It is believed that dolomite aggregates can react with the alkalis from the cement, dissolve and form calcite and brucite (Katayama, 2004). Much less is known about the so called alkali carbonate reaction (ACR). more Chemical alteration of concrete has gained much attention over the past years as many cases of deterioration due to sulphate attack, thaumasite formation (TSA) or alkali silica reactions (ASR) have been reported in various constructions (Schmidt et al, 2009). Al2O3, Fe2O3, Mg0, CaO, SO3 and H2O% by weight proves to be suitable to characterize silicic, advanced argillic and argillic alteration.Ĭhemical alteration of concrete has gained much attention over the past years as many cases of de. ![]() Based on these results a general chemical characteristic for alteration assemblages in epithermal acid-sulphate districts is presented. The calculations indicate that for the formation of the altered rocks and their zonal distribution the elements of the latitic precursor rock, a volcanic source for S, V, and Sr and probably exogenic water were necessarily involved. The results of the mass change calculations of major, minor and trace elements suggest that the secondary mineral associations and their zonal arrangement at Gossendorf have been formed by a strongly acidic hydrothermal solution rich in SO42−, which underwent chemical variations by reaction with the latite. H2O could have been of exogenous and/or endogenous origin. The chemical species added to the rock during alteration, SO3, V2O3, and SrO, probably originated from a volcanic source. The mass exchange was accompanied by a moderate average decrease in volume of 6.6%. the difference of elemental gains and losses, shows a net mass loss of about 14.60 g. For one altered rock characterizing theoretically the alteration processes in Gossendorf, mass grains were calculated for SO3, H2O, V and Sr, and mass losses for SiO2, Al2O3, Fe2O3, MnO, Mg0, CaO, Na2O, K2O, P2O5, Cr, Co, Ni, Cu, Zn, Rb, Y, Zr, Nb and Ba with respect to an unaltered latite. The gains depend on the newly formed minerals, the losses, however, on the increase of the porosity in the altered rocks. Drastic differences in gains and losses of certain elements which refer to the different alteration conditions were found to exist not only between different alteration zones but also within such zones. ![]() All elements investigated were mobilized during the hydrothermal acid-sulphate alteration process, except Ti, which was selected as the immobile monitor element to calculate mass changes. The associations occur in a zonal arrangement and correspond to the characteristics of the silicic, advanced argillic and argillic alteration terminology. more ABSTRACT The Tertiary latitic rock from Gossendorf, in the Gleichenberg Volcanic Area, Styria, Austria, has in places been completely altered to various associations of the secondary minerals opal-C/-CT, alunite, kaolinite, and montmorillonite. Some of the mineral associations, however, may not be explained by a single alteration process, but must be regarded as the result of multi-stage alteration in which alteration products from weak leaching are super-imposed on alteration products from intense leaching.ĪBSTRACT The Tertiary latitic rock from Gossendorf, in the Gleichenberg Volcanic Area, Styria, Au. The results of experimental alteration tests on the latitic rock in open hydrological systems suggest that these secondary minerals and some of the associations observed in the field as well as their zonal distribution, may have been formed by an originally strongly acid solution rich in SO42- which, undergoing progressive chemical variation by reaction with the rock, exhibits a chemical gradient. These associations occur in a zonal arrangement, in which the innermost part has been totally altered to opal and moreover has retained its original latitic structure. ![]() more Summary The latitic rock mined at the Gossendorf open pit in the Gleichenberg Volcanic Area of Styria, Austria, has in places been completely altered to various associations of the secondary minerals opal-C/-CT, alunite, kaolinite and montmorillonite. Summary The latitic rock mined at the Gossendorf open pit in the Gleichenberg Volcanic Area of St. ![]()
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