Investigation of Pozzolanic Activity Indexes of Pasinler Obsidian and Zinc Slag

Pozzolanes are mineral additives that have been widely used in concrete production recently. The main purposes of pozzolana additives used in concrete are to provide economy and improve various properties of concrete. In this study, obsidian mineral which located in Pasinler District of Erzurum Province and has high amount of reserves in the world with high silica content, and zinc slag which occurring during the production of zinc metal, in the metal industry mainly in Turkey and high production capacity in the world, pozzolanic properties has been investigated. For the pozzolanic activity test, mortar samples were produced by using 5, 10, 15, 20 and 25% obsidian; 2.5, 5, 7.5 and 10% zinc slag instead of cement. Samples produced for the determination of pozzolanic activity index were kept at 7 and 28-days standard cure. At the end of the curing period, pozzolanic activity indexes were determined on the basis of compressive strength. As a result of the pozzolanic activity test, the highest pozzolanic activity value was obtained at the rate of 15% for obsidian and 5% for zinc slag. When the results are examined, it is determined that both materials can be used as pozzolan instead of cement.