Title: Chloride Ions Penetration and Carbonation in Alkaline Activated Slag

Author(s): Douglas Everton Cadore, Lucas Ceconi Kretschmer, Carlos Eduardo de Morais Lavandoski, Caroline Angulski da Luz, and Marcelo Henrique Farias de Medeiros

Publication: Symposium Paper

Volume: 326

Issue:

Appears on pages(s): 24.1-24.8

Keywords: alkaline activated cement, durability, chloride ions, carbonation

DOI: 10.14359/51711006

Date: 8/10/2018

Abstract:
Granulated blast furnace slags (GBFS) are by-products from pig iron manufacturing process, and widely used as supplementary cementing materials (SCMs) to Portland cement (PC) to obtain GBFS-Cement blends. In Brazil, PC can have up to 70% of GBFS to obtain PC III which presents good durability properties. On the other hand, alkaline activated cement (AAC) can be obtained from wastes such as fly ash or even GBFS, which are activated by solutions of sodium hydroxide (NaOH), potassium hydroxide (KOH) and silicates, without calcination process and, in this case, are denominated alkaline activated slag (AAS). In addition to their good environmental properties, AAS also present good mechanical characteristics. Then, the goal of this study was to contribute to investigation about durability of AAS, in this case, chloride ions penetration and carbonation. Therefore, samples of concrete made with AAS were subject to test of chloride ions penetration according to ASTM C1202:2012 and to carbonation test according to a specific method. Concrete made with PC with a good behavior to aggressive environment was used as comparison. The comparative analysis showed that the penetration of chloride ions was lower in AAS. However, AAS samples presented higher carbonation depths than PC samples after 16 weeks.