The Influence of Chemical Activators on the Hydration Behavior and Technical Properties of Calcium Sulfoaluminate Cements Blended with Ground Granulated Blast Furnace Slags

• Main Authors: Milena Marroccoli, Antonio Telesca
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Buildings
• Subjects: low-CO₂ binders; calcium sulfoaluminate cements; supplementary cementitious materials; ground granulated blast furnace slag; hydration; expansion/shrinkage
• Online Access: https://www.mdpi.com/2075-5309/11/7/268

The manufacture of Ordinary Portland cement (OPC) generates around 8% of the global CO₂ emissions related to human activities. The last 20 years have seen considerable efforts in the research and development of methods to lower the carbon footprint associated with cement production. Specific focus has been on limiting the use of OPC and employing alternative binders, such as calcium sulfoaluminate (CSA) cements, namely special hydraulic binders obtained from non-Portland clinkers. CSA cements could be considered a valuable OPC alternative thanks to their distinctive composition and technical performance and the reduced environmental impact of their manufacturing process. To additionally reduce CO₂ emissions, CSA cements can also be blended with supplementary cementitious materials. This paper investigates the influence of two separately added chemical activators (NaOH or Na₂CO₃) on the technical properties and hydration behavior of four CSA blended cements obtained by adding to a plain CSA cement two different ground granulated blast furnace slags. Differential thermal-thermogravimetric, X-ray diffraction and mercury intrusion porosimetry analyses were done, along with shrinkage/expansion and compressive strength measurements.