Strength Performance and Microstructure of Calcium Sulfoaluminate Cement-Stabilized Soft Soil

Calcium sulfoaluminate cement (CSA) was used to stabilize a type of marine soft soil in Dalian China. Unconfined compressive strength (UCS) CSA-stabilized tested and compared ordinary Portland (OPC); meanwhile the influence amounts gypsum CSA contents stabilized soils on were investigated. X-ray diffraction (XRD) tests employed detect generated hydration products, scanning electron microscopy (SEM) conducted analyze microstructures soils. The results showed that UCS at 1, 3, 28 d firstly increased then decreased with increasing from 0 40 wt.%, exhibited highest when content equaled 25 wt.%. When mixing OPC same, had significantly higher early (1 3 d) than OPC. For wt.% gypsum, monosulfate (AFm) detected as major product. As for certain intensity ettringite (Aft) sample hydrating without but tiny peak AFm also could be 15 d. Additionally, AFt tended decrease slightly, residual In microstructure OPC-stabilized soils, hexagonal plate-shaped calcium hydroxide (CH) constituted skeleton structures, clusters hydrated silicates (C-S-H) gel adhered particles crystalline sizes increasing; meanwhile, aluminum (AH3) phase observed adhere strengthen interaction.