AN FTIR AND XPS INVESTIGATIONS OF THE EFFECTS OF CARBONATION ON THE SOLIDIFICATION STABILIZATION OF CEMENT-BASED SYSTEMS-PORTLAND TYPE-V WITH ZINC

The effects of carbonation on the solidification/stabilization (S/S) o f zinc using Portland cement Type V (OPC) has been investigated by X-r ay photoelectron spectroscopy(XPS) and Fourier transform infrared spec troscopy (FTIR). The FTIR results indicate that carbon dioxide reacts with the metal-bonded and hydrogen-bonded hydroxides [CaZn2(OH)6.2H2O] generally present in zinc-doped Portland cement (Zn-OPC) samples. XPS examinations of the carbonated products of the undoped and doped (Zn- OPC) samples indicate that the resulting silica phases have chemical s tates different from standard silica gel. Both FTIR and XPS results su ggest that carbonation promotes polymerization of the SiO4 units prese nt in OPC matrix. The chemical states of the surface components obtain ed by XPS analysis are discussed in the light of polymerization of the silicates.