Soluble zinc salts added to cement mix water are generally agreed to retard hydration. The role of zinc in clinker is, however, less well-established. Experiments are reported on clinker stimulants and real industrial clinker meals, the latter. doped with 1.5 wt% ZnO. Contrary to findings in the literature, relatively, little zinc goes into solid solution in the main clinker phases: much is present in the interstitial phases as a solid solution based on 6CaO . 3ZnO . 2Al(2)O(3). Supplementary studies of the CZA system disclose the existence of two ternary phases. C(6)Z(3)A(2) and C(3)ZA(2). Both are cementitious in combination with Ca(OH)(2) or gypsum, or with both. ZnO at 1.5 wt% clinkered in industrial meal, does not affect set times but enhances the rate of strength gain. Zinc remains relatively insoluble, with aqueous Zn concentrations of stimulants not exceeding 2.2 ppm.
|Number of pages||7|
|Journal||Advances in Cement Research|
|Publication status||Published - 2000|