Abstract
Turkey has 955,297 thousand tonnes of B2O3 reserves which correspond to 72.1% of the world. Colemanite (Ca2B6O11·5H2O), ulexite (NaCaB5O9·8H2O) and borax (tincal) (Na2B4O7·10H2O) are the most important boron minerals that are used in production of boric acid and different kinds of borates. During these production processes, boron including wastes form and these wastes pollute the environment. To minimize the pollution caused by these wastes, they are evaluated in different kinds of processes such as cement and concrete production. Borogypsum is one of the boron wastes that is used in cement mortar production. In this study the aim was to compare the calcined and non-calcined borogypsum addition to clinker and also investigate its effects on cement mortar. Moreover, to see how borogypsum addition affected the cement properties, different ratios of borogypsum between 1% and 7% were used. Also setting time and consistency analyses were applied to fresh mortar; compressive strength and splitting tensile strength of 3, 7, and 28 days were investigated according to the Turkish Standard (TS EN 196-1). X-ray diffraction (XRD) analysis was realized for characterization of the chemical structure of 28-days mortars. 3% was the ratio at which the optimum results were obtained for both calcined and non-calcined borogypsum.