Carbonated wollastonite clinker (CS) may be suitable as supplementary cementitious material (SCM) for mortar and concrete. The microstructure of unground CS clinker, carbonated CS slurry and a mortar blended with carbonated CS are investigated by scanning electron microscopy. Additionally, a reference mortar with pure Portland cement and one with a cement replacement level of 30 mass-% by carbonated CS are produced to assess its contribution to compressive strength development. The calcium silicates are decalcified during carbonation resulting in CaCO3 and amorphous SiO2 . The latter reacts when used as SCM in mortar influencing the Ca/Si ratio of calcium-silicate-hydrate and contributing to compressive strength development.
Keywords: carbonation; compressive strength; microstructure; supplementary cementitious material; wollastonite.
© 2021 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.