2Yildiz Technical University, Department of Chemical Eng., Esenler, ISTANBUL
The cement industry generates approximately 5% of man-made carbon dioxide (CO2) emissions worldwide. Today, research interest in reducing carbon dioxide emissions in the cement industry isincreasing rapidly. For this purpose, alkaline-activated materials or geopolymers, have become an important research topic. Alkaline-activated materials use waste such as fly ash, blast furnace slag, and silica fume without any clinker. Alkaline-activated binders have been investigated for many years owing to their environmentally friendly properties, but they have not progressed beyond research activities owing to production problems and a lack of standardization.
In this study, the effects of retarders on mortar samples produced by alkaline activation were investigated. Blast furnace slag obtained from Eregli was used as the binder. Alkaline activation was carried out using a mixture of sodium silicate and sodium hydroxide as the activator. The setting times were delayed using boric acid and boric acid slurry obtained from Etimaden Bandırma plants. The effects of boric acid and boric acid waste on compressive strength, setting time, and consistency were determined. The carbonation reactions, chloride migration coefficients, alkaline silica reactions, and water absorption properties of the mortar mixtures were determined according to EN 13295, NT Build 492 standard, the accelerated mortar method and ASTM C1403 standard, respectively.