Investigation of usability of tuffs called as Bayburt stone as a mineral admi̇xture in cement production

Cement is one of the most important constituents which effect strength and cost of a construction. However, cement production causes approximately 8% of the world CO2 production. Therefore, waste and new ingredients have been using in cement production in order to enhance properties and cost effectiveness. Pozzolans are the most common way to get these purpose. White, green and yellow colored Bayburt stones have high alumina and silica structures, and so they have pozzolanic reactivity. Quarry works of these stones cause roughly 70% of wastes. In this study, grinded Bayburt stones were replaced with Portland cement at different ratios in blended cement production. This application was performed to reduce costs of cement and to enhance some of properties of cement. Thus, it is aimed to produce of CEM II and CEM IV cements. In experimental study, initially Bayburt stones were taken from industry of waste region in Bayburt province, and afterwards they crushed by laboratory type crusher. Following, materials were grinded as D90: 45 µm by ball mill. Grinded three different colored Bayburt stone were replaced with Portland cement at ratios 0%, 5%, 10%, 15%, 20%, 30% and 40%, respectively. After that, Standard consistency, initially and final setting times and soundness tests were performed according to the TS EN 196-3 on produced blended cements. Furthermore, 4x4x16 cm sized mortar specimens were produced according to the TS EN 196-1 with using produced blended cements. With these mortar specimens, Compressive and flexure tests were performed at 2nd, 28th, 90th and 270th days according to TS EN 196-1; water absorption test were performed at 2nd, 28th, 90th days according to the ASTM C642; capillary absorption test were performed at 90th day according to the ASTM C1585 and elevated temperature effect tests were performed at 90th day . Moreover, mineralogical and microscopically analysis were performed by using X-Ray Diffraction Spectroscopy (XRD) and Scanning Electron Microscopy (SEM) at 7th and 90th days. According to the results obtained from the experiments; Due to the low specific gravity, 28 compressive strengths and low water permeability of the cements produced, they can be used in the production of BT doped cement. It has been determined that the properties of BT substituted cement are in accordance TS EN 197-1. As a result of this research, it was determined that 20% of Bayburt white stone, 30% of Bayburt green stone and 40% of Bayburt yellow stone could be used as substitute for instead of Portland cement.