A Review of Durability and Strength Characteristics of Alkali-Activated Slag Concrete

• Main Author: Osama Ahmed Mohamed
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Materials
• Subjects: alkali activated slag; carbonation; shrinkage; alkaline activator; hydration products; alkali-silica reaction; curing temperature; fly ash; silica fume
• Online Access: https://www.mdpi.com/1996-1944/12/8/1198

Alkali-activated slag (AAS) is a promising alternative to ordinary Portland cement (OPC) as sole binder for reinforced concrete structures. OPC is reportedly responsible for over 5% of the global CO₂ emission. In addition, slag is an industrial by-product that must be land-filled if not re-used. Therefore, it has been studied by many investigators as environmentally friendly replacement of OPC. In addition to recycling, AAS offers favorable properties to concrete such as rapid development of compressive strength and high resistance to sulfate attack. Some of the potential shortcomings of AAS include high shrinkage, short setting time, and high rate of carbonation. Using ground granulated blast furnace slag (GGBS) as an alternative to OPC requires its activation with high alkalinity compounds such as sodium hydroxide (NaOH), sodium sulfate (Na₂SO₃), sodium carbonate (Na₂CO₃), or combination of these compounds such as NaOH and Na₂SO₃. The mechanism of alkali-activation is still not fully understood and further research is required. This paper overviews the properties, advantages, and potential shortcomings of AAS concrete.