Stabilization of Dicalcium Silicate-Zn Composite Approaching Layered Double Hydroxide Structure for Bioactive Cement Applications

Abstract

Layered Double Hydroxide (LDH) is ionic clay that is characterized by the union of metal cations and OH- hydroxides. LDH composites exhibit considerably high releasing and recharging capacity and have applications as bioactive cements. They can be prepared by direct co-precipitation of metal salts at controlled pH. The preparation is carried out from an acid solution of Zn (NO3)2.6H2O, Al (NO3)3.9H2O and a basic solution of Na2CO3 and NaOH, with a Zn/Al ratio = 3, the pH is stabilized between 9 and 9.5 at a constant temperature of 45°C. The objective of this study is to incorporate Zinc and Aluminum elements at different percentages in dicalcium silicate phase to produce C2S phase incorporating LDH composite. The characterizations of the developed phases by XRD and SEM indicate the formation of stoichiometric LDH phases Zn6Al2(OH)16CO3.4H2O and non-stoichiometric Zn0.61Al0.39 (OH)2(CO3)0.195.xH2O, the incorporation of Zn in the belitic C2S phase and not Al. The obtained micrographs by SEM(EDAX) analysis show new morphology of the stabilized composite.