Performance evaluation of calcium sulfoaluminate as an alternative stabilizer for treatment of weaker subgrades

Problematic soils cause significant damage and distress in pavements from moisture induced volume and strength changes. Calcium based stabilization are well known to permanently stabilize expansive soils. Traditional calcium-based stabilizers typically include lime and cement for ground improvement of plastic clays to enhance strength. Calcium Sulfoaluminate (CSA) cement can be an effective and sustainable alternative with improved environmental considerations. The application of CSA cement to treat expansive/weak subgrade soils are limited. This research paper examines the efficiency of CSA cement compared to traditional calcium-based stabilizers in road pavements. The comprehensive laboratory study evaluates the durability of stabilized soils by assessing the mechanical performance under the effect of moisture impacts by means of investigating the bearing capacity, unconfined compressive strength (UCS) during wet-dry cycles, the resilient modulus (Mr) and UCS across practical moisture ranges and mechanical strength from vacuum saturation and moisture susceptibility testing. Results from the study reveals that the calcium-based stabilizers are effective in treating expansive soils by increasing strength across the moisture ranges tested. All stabilized soil specimens showed an increase in UCS after the completion of one wet-dry cycle and resistance to both vacuum saturation and moisture susceptibility testing. While the addition of CSA cement treatment showed considerable improvements over untreated expansive soils, it is not as effective in improving the durability performance of expansive soils compared to traditional cement and lime stabilizers under tested conditions. However, the use of CSA cement has high potential for improving weak subgrade conditions through sustainable ground stabilization.