Strength of high water-content marine clay stabilized by low amount of cement

Abstract

An ideal solution for disposal of large volumes of unwanted dredged clays is to stabilize and use them as fill materials for land reclamations. This kind of stabilized dredged fill (SDF) requires a lower cement amount (Cm) compared with traditional cement-treated soils. Strength behavior might be different for mixes within the inactive zone (lower Cm) and those within the active zone (higher Cm). The SDF is fully/partially within the inactive zone. A new set of unconfined compressive strength (qu) data as well as qu data compiled from literature covering both lower and higher Cm are analyzed. First, main parameters governing qu of cement-stabilized clays are identified: (1) cement amount (Cm), and (2) water content (W). Then, qu behaviors in the inactive zone and active zone are compared. Results indicate that a nonlinear normalized qu-Cm trend is commonly observed in the inactive zone whereas a linear one is observed in the active zone. In both zones, the normalized qu-W curve (or normalized qm-Cm curve) is unique for a given soil type, regardless of Cm (or W). The key conclusion is that Cm and W should be considered as separate variables in the estimation of qu, rather than in a combined form such as water:cement ratio (W/Aw). The practical outcome is the development of an empirical formula as a function of Cm and W for estimation of qu of cement-stabilized clays. Validation results show the proposed formula is applicable to both inactive zone and active zone. © 2013 American Society of Civil Engineers.