Composite alkaline activator on cemented soil: Multiple tests and mechanism analyses

Adding cement in to reinforce soft soil has been a widely used technique in engineering projects. However, there exist great concerns over the issues of low early strength and massive resources consumption. This study tested a composite alkaline activator of sulfate and alkali aluminate in cemented soil by Unconfined Compressive Strength (UCS) test. Multiple analyses of X-ray Diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), Thermo Gravity Analysis (TGA), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Mercury Intrusion Porosimetry (MIP) were carried out to explore the activation mechanisms of the activator under different additions over curing periods. Test results revealed that UCS of stabilized soil was greatly improved in especially early periods with proper activator dosages. Hydration and pozzolanic reaction extents were accelerated with proper additions, while significant retardation for products of hydration and pozzolanic products was observed with excessive dosages.