1995/07/01 by Stephen Kwan, Judith L. LaRosa, Michael W. Grutzeck · 3 citations
Engineering · Materials Science · Chemistry · #Concrete and Cement Materials Research #Clay minerals and soil interactions #Zeolite Catalysis and Synthesis
paper · doi:10.1111/j.1151-2916.1995.tb08910.x
openalex publication_date 1995/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/23
Strätlingite (2CaO·Al 2 O 3 ·SiO 2 ·8H 2 O) is a complex calcium aluminosilicate hydrate commonly associated with the hydration of slag‐containing cements or other cements enriched in alumina. Strätlingite can coexist with the hydrogarnet solid solution [hydrogarnet (3CaO·Al 2 O 3 ·6H 2 O)‐katoite (3CaO·Al 2 O 3 ·SiO 2 ·4H 2 O)] and calcium silicate hydrate (C‐S‐H). Since Strätlingite is present in many blended cements, the knowledge of strätlingite's characteristic silicate anion structure and how aluminum is accommodated by the structure is important. Phase pure Strätlingite samples have been synthesized from oxides in the presence of excess water and from metakaolinite, calcium aluminate cement, CaO, NaOH, and water. The samples were characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) and then further examined using 29 Si, with and without cross‐polarization (CP), and 27 Al solid‐state magic angle nuclear magnetic resonance spectroscopy (MASNMR). For the most part, NMR data for these strätlingites corroborate structural information available in the literature. The aluminum atoms are both tetrahedrally and octahedrally coordinated, and the silicon atoms exist predominantly as Q 2 , Q 2 (1Al), and Q 2 (2Al) species. The presence of alkali affects the structure of strätlingite in subtle ways, significantly reducing the Al IV /A1 VI ratio.