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What is alkali activated slag?

What is alkali activated slag?

Alkali-activated slag (AAS) and AASC (alkali-activated slag concrete) are made by activating granulated blast furnace slag (GGBS) with alkali solutions. The Portland cement can be replaced entirely, thus offering a substantially reduced environmental impact over conventional concrete.

What are properties of slag cement?

Properties of these slag cements are broadly similar to those of portland cement, but they have a lower lime content and a higher silica and alumina content. Those with the higher slag content have an increased resistance to chemical attack.

What is alkali activated concrete?

Alkali-activated concrete (AAC) is defined as a class of cement-free concrete that is an alternative to Portland cement concrete (PCC). Instead of using ordinary portland cement (OPC) and water, AAC uses other supplementary materials like blast furnace slag (BFS) or fly ash (FA) along with an alkaline activator.

What is activated slag?

Abstract: 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.

How do you activate slag?

Most applications employ the use of high pH values in the pore solution (> 13.0) to accelerate the corrosion of the glass network of the slag. It is shown in this work that activation is also possible by lowering the pH to a range between 11.8 and 12.2 by the addition of calcium hydroxide and soluble calcium salts.

Is slag cement good for construction?

Portland Slag Cement, commonly known as PSC, is blended cement. PSC has been voted as the most suitable cement for mass construction because of its low heat of hydration.

Can slag be used under concrete?

Steel slag is not recommended for use in rigid confined applications – such as concrete aggregate, base or fill under structures or floor slabs, or backfill against structures or bridge abutments. Durability: The slags are highly resistant to weathering action such as freezing and thawing.

Who invented geopolymer concrete?

Joseph Davidovits
In the 1950s, Viktor Glukovsky, of Kiev, USSR, developed concrete materials originally known under the names “soil silicate concretes” and “soil cements”, but since the introduction of the geopolymer concept by Joseph Davidovits, 1991, the terminology and definitions of ‘geopolymer’ have become more diverse and often …

Does slag Harden?

Slag cement improves many of the strength and durability properties of hardened concrete. Slag cement is a hydraulic binder that, like portland cement, reacts with water to form cementitious material (calcium-silicate hydrate or CSH).

What activates a blast furnace?

The use of calcium chloride or calcium bromide allows for the activation of blast furnace slag due to the maintenance of a high calcium ion concentration and reduction of pH in the pore solution.

What is slag cement disadvantages?

Disadvantages of Blast-Furnace Slag Cement Early Strength is low; therefore, it cannot be used in Reinforced Cement Concrete (RCC) works. As the initial setting time is high, this cement is not used for emergency or repair works.