نوع مقاله : یادداشت فنی
نویسندگان
1 گروه مهندسی عمران، دانشگاه فردوسی مشهد، ایران
2 دانشگاه فردوسی مشهد
3 گروه مهندسی عمران، دانشگاه کوفه، نجف، عراق
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
This research explores the compaction behaviour of Iraqi gypsum-sand soils stabilized with cement and cement kiln dust (CKD) at varying additive percentages (1%, 3%, 5%, and 7%) under different compaction levels (90% and 95%). Laboratory experiments were conducted using a modified oedometer to obtain Soil Water Retention Curves (SWRC) and assess the impact of matric suction on soil compressibility and water retention. The study reveals that both cement (3%) and CKD (5%) significantly improve the water retention capacity of the soil, reduce hysteresis effects, and enhance its resistance to compaction and swelling. These additives positively influence the soil’s water-holding capacity, thereby improving its performance in both saturated and unsaturated conditions. The Van Genuchten model was effectively used to describe the SWRC, demonstrating that cement outperforms CKD in terms of hydraulic behaviour due to the formation of stronger cementitious bonds, which contribute to better soil structure and stability.
Additionally, the improvement analysis highlights that stabilization at higher compaction levels (95%) and under conditions of increased matric suction results in greater effectiveness, with cement-treated soils showing the most significant improvement in performance. This is particularly critical for applications in environments where soil behaviour under varying moisture content is a key factor. Furthermore, Scanning Electron Microscope (SEM) analysis confirmed the microstructural enhancements caused by cement hydration and the pozzolanic reactions of CKD, which help form a more stable and cohesive structure at the particle level.
The results showed that adding 3% cement and 5% CKD reduced hysteresis and improved the SWRC curve, especially at 95% density. Also, at 95% density and 60 kPa suction, cement reached an improvement factor of 83% and CKD reached 33%.
The findings underline the importance of both the type of stabilizing agent and the compaction level in improving the hydraulic properties and long-term stability of Iraqi gypsum-rich sandy soils. This research emphasizes the potential of using cement and CKD for soil stabilization, particularly in regions where moisture variability and soil behaviour are significant challenges. These insights contribute to the development of more durable and sustainable soil stabilization techniques in geotechnical engineering.
کلیدواژهها [English]
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