Estokova A., Kovalcikova M., 2013, The Study of Zeolite Based Cement Composites in Aggressive Environment, Chemical Engineering Transactions, 35, 1123-1128.
The exposition of concrete and cement composites to the aggressive environment is resulting in damages in the structures before the expected service life. Prolonging the service life of concrete composites through enhancing the mechanical and durability properties has gained great importance in recent years. It is possible to achieve environmental and economical benefits with the utilization of pozzolanic mineral additives in cement production. The use of zeolite as partial replacement of Portland cement prevents alkali-silica reaction by decreasing the alkaline ion concentration in the pore solution in concrete via ion exchange, adsorption and pozzolanic reaction, therefore the formation of alkali silicate gel is eliminated and the interface is improved. The papers presents the results of the comparative study of the resistance of the Slovak origin zeolite based cement composites and cement composites of ordinary CEM I Portland cement exposed to the sulphate environment. The various aggressive media was used for the experiment: sulphuric acid with pH 3 and 4.2 and magnesium sulphate solution with the concentrations of 3g/L and 10g/L. The laboratory experiment proceeded during 90 days under model conditions. The mass changes of samples as well as the changes in the elemental concentrations of calcium and silicon in liquid leachates were observed. The leaching of the calcium and silicon from concrete specimens has been studied by using X – ray fluorescence method (XRF). The pH values of leachates increased to the alkali region for all leachates as expected. Surprisingly, higher leaching ratio of calcium and silicone ranged 1.29 - 8.18 and 2.32 -20.44 for Si and Ca, was confirmed in case of the zeolite based cement composites when comparing to the ordinary cement composites.
