Stabilization of Coastal Soils to Improve Resiliency of Transportation Infrastructure after Storm Surge Events

Hurricane storm surges can significantly damage transportation infrastructure and consequently hinder access routes for relief and quick recovery of the affected communities. Problematic coastal soils are often weak in strength and stiffness and highly erodible, which causes distress to the pavements and arterial roads after flooding events. As a result, enhancement of the engineering properties of such weak soils is essential to provide resilient coastal infrastructure systems. A research study was designed to assess the efficacy of calcium-based stabilizers including lime and cement on the strength, stiffness, and erodibility characteristics of coastal soils. Laboratory studies were conducted on natural sandy and clayey soils as well as 7-day cured cement-treated sandy soil and 14-day cured lime-treated clayey soils to evaluate the improvements in resilient modulus, unconfined compressive strength, and erodibility. Specimens were also tested after soaking in the water bath for 6 and 24 h to replicate storm surge aftereffects. Test results indicated that the application of stabilizers significantly increased the strength and stiffness values for treated clayey and sandy soils. The treated clayey soils retained an average 150% higher strength after moisture conditioning and also recorded an average of 60% less degradation in the resilient moduli values as compared to untreated soils. Similar results were also observed for cement-treated sandy soils. The stabilized specimens also illustrated a reduction in the erodibility coefficient, from 0.1 to 0.02 cm3/N-s in lime-stabilized clay and 8 to 0.007 cm3/N-s in cement-stabilized sand. Consequently, the behavior of the natural soils changed from erodible or very erodible soils to resistant or very resistant soils after chemical stabilization. Overall, the study provides a comprehensive understanding of the efficacy of calcium-based stabilizers in improving the resiliency of transportation infrastructure, which could extend the service life and provide quick recovery from coastal hazards.