Novel hydrothermal synthesis method for tobermorite fibers and investigation on their thermal stability

Tobermorite fibers have been successfully synthesized by hydrothermal reaction at 200°C under the pressure of 2 MPa after 3–10 h using a Ca(II)–EDTA complex precursor. XRD patterns, TG-DTA analysis, and SEM observations show that the products are needle-like tobermorite fibers, which have diameter, length, and aspect ratio in the range of 0.1–10, 40–100, and 20–80 μm, respectively. The fibers can maintain their shapes up to 1150°C during the heat treatment.