Marine Geo-Polymer Cement Treated with Seawater, Alkaline Activators, Recycled Particles from Paste, and Recycled Particles from Glass.

This study aims to develop the marine geo-polymer cement that was produced with seawater, recycled particles from paste, recycled particles from glass, and alkaline activators, including NaOH or NaO·3.3SiO. The physicochemical properties and strength of MGPC were investigated with a Uniaxial Compression Test, Particle Size Analysis, Energy Dispersive Spectrometer, X-ray Diffraction, and Thermal-field Emission Scanning Electron Microscopy. The results indicated that the main hydration products in MGPC were calcium carbonate (CaCO), silica (SiO), sodium aluminosilicate hydrate (NaO·AlO·xSiO·2HO, N-A-S-H), and aluminum calcium silicate hydrate (CaO·AlO·2SiO·4HO, C-A-S-H). The calcium carboaluminate (3CaO·AlO·CaCO·32HO, CO-AFm) in MGPC was converted into CaCO and Friedel's salt (3CaO·AlO·CaCl·10HO), which prompted the carbon sequestration. The microstructure of MGPC prepared using NaO·3.3SiO was based on RPG as the matrix, with N-A-S-H, C-A-S-H, and fibrous AFt growing on the periphery. This structure reduces the impact of the alkali-silica reaction on the material and improves its compressive strength. Therefore, the MGPC developed in this study shows the exact benefits of freshwater and natural minerals saving, carbon sequestration, and damage resistance.