WATER RETENTION AND SWELLING CHARACTERISTICS OF DIATOMACEOUS EARTH TREATED EXPANSIVE SOIL

Abstract

Expansive soils pose significant challenges to highway embankments due to their high swell-shrink potential, which is exacerbated by desiccation cracking. While diatomaceous earth (DE) has shown promise in mitigating these issues, the underlying mechanism in expansive soils remains poorly understood. This study investigates the mechanism of diatomaceous earth (DE) addition in improving the behavior of expansive soils by examining soil-water retention and swell characteristics. The filter paper method was employed to assess soil water retention, while a one-dimensional swell compression test assessed swelling potential and swell pressure. Results indicate that adding 10%DE_SF in mass enhances water retention capacity and air entry suction, thereby improving the soil structure and reducing desiccation cracking. Furthermore, the swell potential and swell pressure of the expansive soil were significantly reduced, highlighting the effectiveness of DE treatment in mitigating soil expansion. These findings contribute to a better understanding of the role of DE in expansive soil stabilization. However, future research should focus on detailed microstructural analysis to explain the mechanisms at the particle level and field-scale validation to ensure practical applicability.