Zeolite is a natural mineral that is used in many different areas such as agriculture, fisheries, industry and conservation of environment. Besides that, zeolite also has potential to be used as pozzolanic materials as it contains high silica contents that are expected to react with Ca(OH)2 to improve the performance of concrete materials. In this research study, the influence of zeolite as a partial substitution of cement in the properties of concrete has been studied through comparison of test results of zeolite chemical composition and the mechanical strength of mortar/ concrete containing zeolite. The type of zeolite materials used is natural zeolite from Lebak, Banten Province. In this study, the natural zeolite used is treated first. The treatment of zeolite is an effort to improve the performance of natural zeolite. There are 3 (three) methods used, i.e heat treatment with temperature of 250 oC (ZAF), immersion in 0.8M NaOH solution (ZAK1) and immersion in 2 M NH4Cl solution (ZAK2. In the mortar and concrete samples, the cement contents are substituted with 20% and 10% zeolite, respectively. Reactivity of zeolite with Ca(OH)2 is also measured in this study by titration of Ca(OH)2 contents in the sample of zeolite-Ca(OH)2 solution.

The results of this study indicate that the natural zeolite originating from Lebak, Banten Province and also the treated one can be used effectively as supplementary cementing materials or cement replacement in concrete mix. When used in the concrete mix, both the untreated and treated zeolite consume quite significant amount of Ca(OH)2.