ارزيابي سنگدانه هاي مستعد واكنش قليايي در چند منطقه كشور

Evaluation of Aggregates Susceptible to Alkali Reactivity in Certain Regions of Iran

In rock materials there are reactive silica including opal, chalcedonic, tridolomite, etc. which are reactant and generally present in aggregates in the production of concrete. These aggregates react with alkali derived from cement. An alkali - siliceous gel is formed due to this active silica which is then expanded and swollen over a period of time and gradually deteriorates the concrete. In execution of civil projects the potential of alkali reactivity of aggregates should be studied by means of required chemical, accelerating and complementary tests before using in concrete production. In this paper aggregates selected from quarries of different cities in Azerbeydjan Province are assessed in order to determine the reactivity aggregates of to be used in the concrete of several industrial projects, having conducted accelerating mortar prism test ASTM C 1260, chemical methods ASTM C 289, long term Concrete prism CSA-A 23, 2-14A. Besides, aggregates deterioration test by means of sodium sulfate analysis and chemical test were carried out to determine the overall sulfate and chloride contents. Consequently the tests results have been used in the procedures of concrete mixing plan/design.