Examination of mechanical and durability properties of various types of fly ash produced by using alkali activated mortars

Cement has been the most important building material in construction industry from the 19th century until today. With this, however, the cement sector is known as a fact of affecting the ecological balance adversely by excavating millions of tons of clinker raw materials from the land and releasing carbon dioxide gas into the atmosphere during the high-temperatured incineration furnaces of clinker. However cement production seems to be an indispensable sector of today and future, in terms of sustainability of environmental protection activities, producing alternative building materials to the cement binder is also continuing rapidly. It is possible to produce high-strength mortar as a result of activating various alkaline fly ash. In this study F Class fly ash is obtained from Tunçbilek Thermal Power Plant and C Class fly ash obtained from Kangal Thermal Power Plant, sand, water, sodium hydroxide (NaOH) and sodium silicate (nSiO2Na2O) is applied by dry-blending temperature cure. Produced cement mortar samples were immersed in the air cure at room temperature for 28 days. Then flexure and compressive strengths of the samples were tested. Reaching the maximum compressive strength of the sample amount of the activator was determined as the ratio of the appropriate activator. Thus, high strength of F Class and C Class fly ashes that are used in this study have been identified the most suitable activator ratios. With the mixtures the production of the most appropriate activator, as a result of the implementation of different curing temperatures 3,21-50,64 MPa having a compressive strength in alkali activated cement mortar sample was obtained. From the production of these samples, in the period of time up to 1 year strength changes were observed. Then the samples of the produced cement which were activated from the most appropriate activator of F Class fly ash were compared with the cement-bound samples of durability characteristics. In this study, to obtain high strength and toughness in the alkali activated composite as an alternative to cement -bonded composites and to reduce the damage which is given to the environment by the thermal power plants waste product "fly ash" in our country, is aimed. Keywords: Fly ash, alkali, activator, sodium hydroxide, mechanical strength, durability.