Evaluation of the strength and microstructural characteristics of stabilized organic clay soil

Abstract

Organic soils, characterized by high compressibility and low shear strength, pose significant challenges in construction. This study employs the Solidification/Stabilization (S/S) method to assess the strength of organic clay soil, integrating sewage sludge and cement as stabilizing agents. Recognizing the need for effective strategies to overcome the inherent difficulties associated with these soils, the research explores the synergistic effects of sewage sludge and cement. Sewage sludge, introduced at varying percentages (7 %, 14 %, and 21 %), is blended with soil, and the resulting mixtures are treated with cement at dry weight ratios (0 %, 3 %, 6 %, and 9 %). Unconfined compressive strength tests at 7, 14, and 28 days assess soil stability, complemented by scanning electron microscopy (SEM) and X-ray diffractometry (XRD) to elucidate changes in mineralogy and morphology. Cement emerges as the most efficient stabilizer, enhancing the strength of organically treated soils. Strength loss corresponds with increased organic content, attributed to contaminants from sewage sludge hindering the formation of cementitious materials. Notably, the optimal improvement in strength occurs at 7 % organic matter and 9 % cement, emphasizing the delicate balance required for effective soil stabilization, an Unconfined compressive strength of (3700,5200,6100) Kpa was obtained at 7, 14, and 28 days. These findings offer valuable insights for sustainable and efficient soil treatment in construction, addressing the intricate interplay between organic content and cementitious material formation, which underscores practical insights for addressing challenges in environmental and chemical engineering applications.

Keywords

• Cement
• Contaminated soil
• Organic soil
• Stabilization
• Unconfined compressive strength