Alkali activated Slag

In the construction industry are annually consumed approximately 2 billion tons of Portland cement (PC) and the demand is continuously increasing. Moreover, the manufacturing of cement contributes for 5–8 % of the total manmade carbon dioxide emissions.
Since the beginning of this century, alkali activated materials (AAM) are considered high-potential binders for producing green and sustainable concrete. These materials are characterized by good durability, as well as good mechanical properties, such as high early strength, low thermal conductivity, and high resistance to acid and chemical attack.
Precursors for producing AAM are usually industrial by-products rich in alumina and silica, like blast furnace slag (BFS), fly ash, rice husk ash, etc. Moreover, as activator can be used different alkaline aqueous solution, as e.g. silicate, carbonate, hydroxide or sulphate. Use of BFS as binder can decrease the CO2 emission by approx. 80% if compared to OPC on a binder-to-binder basis.
In this project is investigated shrinkage and creep of alkali-activated ground granulated blast furnace slag (GGBFS) coming from Sweden and with a high MgO content (16.1wt%). Alkaline activators used in this investigation included sodium silicate solution, sodium carbonate and a combination of both. Heat and laboratory curing conditions were applied to determine their effects on shrinkage and other related properties of AAS matrixes. Changes of the activators type and dosage, as well as curing conditions are performed in order to evaluate their effect on the AAM properties, such as setting time, workability, strength development, carbonation, hydration temperature, and microstructure.
Contact
Andrzej Cwirzen
- Professor and Head of Subject
- 0920-493387
- andrzej.cwirzen@ltu.se
- Andrzej Cwirzen
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