Dosage Proposal for Stabilization Silty-Clayey Residual Soils in the Northern Region of Santa Catarina State

Objective: This study investigates the dosage of cement and rice husk ash (RHA) for the chemical stabilization of a silty residual soil from the northern region of Santa Catarina, aiming to determine the minimum required contents to ensure adequate unconfined compressive strength under saturated conditions. Theoretical Framework: The research is based on the principles of soil chemical stabilization, emphasizing the use of hydraulic binders, such as cement, and pozzolanic materials, such as RHA, which can enhance the mechanical strength and durability of fine-grained residual soils. Method: Two soil samples were collected and classified according to the Unified Soil Classification System (USCS) as clayey silt and silty sand, with the latter being discarded due to its coarser nature. Specimens were prepared with 4%, 6%, and 8% cement, as well as a combination of cement and 10% RHA, both replacing the dry soil weight. After a 7-day curing period under saturated conditions, the specimens were subjected to unconfined compressive strength testing. Results and Discussion: The 4% and 6% cement dosages, with or without RHA, did not achieve satisfactory strength. The best performance was obtained with 8% cement and 10% RHA, suggesting this as the minimum effective dosage. Research Implications: The findings support soil stabilization projects in the northern region of Santa Catarina, promoting sustainable practices by incorporating agro-industrial waste. Originality/Value: This study demonstrates the technical feasibility of RHA as a complementary stabilizing agent, reinforcing its potential to enhance soil performance in geotechnical applications.