Hydration reactions and their rates have been studied qualitatively in CaO- and P205-rich compositional regions of the system Ca0-Si02-P205-H20. Using aqueous solutions of Ca(N03) 2 • 4H20, Ludox, and H3P04 as starting materials, amorphous powders made by the sol-gel process were reacted with water. Some “curing” reactions were carried out at several temperatures: Room temperature, 90 °C, and under hydrothermal conditions. Some glasses in the phosphate-rich region of the system were also made and hydrated. The hydration products are OH-Ap [OH-Ap = Ca10(PO4)6.(OH)2], Ca(OH)2[CH = Ca(OH)2],C-S-H crystalline, C-S-P-H (C = CaO,S = Si02,P = P205,H = H20) crystalline, C-S-H gel, C-S-P-H gel, Ca (H2P04) 2) H20, and CaHP04. All phases have been identified and characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray analysis (EDAX). The reactivities of the precursor materials and the compositional-structural nature of the hydration products formed are discussed. Some new compositions for “cementlike behavior” have been discovered.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering