Valorisation of iron-rich slags in cement systems: from chemistry to application

Researchers:

• Vincent Hallet 
  
•  Yiannis Pontikes (supervisor)
• Nele De Belie (supervisor)

Description:

There is a large production of non-ferrous slags in Belgium, currently mostly used in low-value applications. Using these slags as substitution for Portland clinker in blended cements presents an opportunity for both valorization of the slags as well as environmental impact reductions of cement. Hence the first goal of this project is investigating the impact of incorporating these slags in blended cements on their properties, including resistance to carbonation, chloride ingress and freeze-thaw, and to compare them with commercially used supplementary cementitious materials, such as fly ash or ground granulated blast furnace slags. Furthermore, contrary to those supplementary cementitious materials, these slags have a high Fe(II) content. As little is known at this point about the resulting phases due to this Fe(II) content, a second goal is to determine the reaction products in the slag-blended cements, specifically focussing on Fe-rich phases. Further improvement of these blended cements may be possible by the use of various additions or by changing the fineness of the slag. Hence some additions, such as limestone, and their impact on the properties are investigated as well, in order to obtain a broader understanding of how these slags can be valorized in various blended cement systems.