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Compaction Control Using Degree of Saturation and Plasticity Index on Tropical Soil Hasbullah Nawir; Laras Dipa Pramudita; Tita Kartika Dewi; Dayu Apoji; Sugeng Krisnanto
Journal of Engineering and Technological Sciences Vol. 55 No. 3 (2023)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2023.55.3.5

Soil compaction in the field is conventionally controlled using maximum dry density, (ρd)max, and optimum moisture content, (w)opt, as the target properties. However, achieving accurate control of these target properties can be difficult due to variation of compaction energy level (CEL) and soil type. Recently, a novel soil compaction control approach using optimum degree of saturation, (Sr)opt, as the target properties has been proposed. It was argued that (Sr)opt can be a better compaction control property as the value is less sensitive to the variation of CEL and soil type. This paper presents an investigation of the compaction characteristics of tropical soils from several locations in Indonesia based on both primary and secondary data. This study was performed by exploring the relationships between (i) dry density (ρd) and Sr, (ii) (ρd) and plasticity index (PI), (iii) (ρd) and CBR, as well as (iv) (ρd) and permeability. This study showed that the (Sr)opt of the soils was 91.2%, with variation between 81.2% and 96.5%. This study also showed that (ρd)max can be related to PI at a given CEL. It is expected that the proposed relationships can be better references for field compaction control practices in Indonesia.

STUDY ON THE CHANGES IN CHARACTERISTICS OF HIGHLY EXPANSIVE SOIL IN CIREBON DUE TO ADDITION OF EGGSHELL POWDER Gerry T Padantha; Billy Tanadi; Hasbullah Nawir
Jurnal Ilmiah Teknik Sipil Vol. 29 No. 2 (2025): Jurnal Ilmiah Teknik Sipil, Vol. 29 No. 2, September 2025
Publisher : Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JITS.2025.v29.i02.p01

Expansive soils, which swell with increased moisture and lose strength compared to their dry state, can cause landslides, structural cracks, and other shrink–swell related issues. Lime treatment is commonly used to mitigate these problems but is unsustainable and leaves a large carbon footprint. As an alternative, eggshell powder (ESP), rich in calcium, is proposed as a stabilizing agent. Soil properties were tested in accordance with ASTM standards. Consistent with Lee and Suedkamp, high-plasticity soil shows no distinct optimum dry density, making it difficult to establish a clear pattern of changes in this property. ESP addition reduces the Atterberg limits and Methylene Blue Value, lowers the swelling potential, and increases the unconfined compressive strength (UCS). The calcium content in ESP decreases the soil’s capacity to swell, although the effect appears limited due to remaining organic components. A significant improvement in UCS was observed with 5% ESP at 14 days of curing, increasing strength from 181.87 kPa to 327.49 kPa, while the most notable reduction in swelling potential occurred with 15% ESP at 7 days of curing. However, both UCS and swelling potential showed no consistent trend, likely due to complex interactions of organic materials in ESP that reduce its effectiveness in soil stabilization.

STUDY ON THE CHANGES IN CHARACTERISTICS OF HIGHLY EXPANSIVE SOIL IN CIREBON DUE TO ADDITION OF EGGSHELL POWDER Gerry T Padantha; Billy Tanadi; Hasbullah Nawir
Jurnal Ilmiah Teknik Sipil Vol. 29 No. 2 (2025): Jurnal Ilmiah Teknik Sipil, Vol. 29 No. 2, September 2025
Publisher : Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JITS.2025.v29.i02.p01

Expansive soils, which swell with increased moisture and lose strength compared to their dry state, can cause landslides, structural cracks, and other shrink–swell related issues. Lime treatment is commonly used to mitigate these problems but is unsustainable and leaves a large carbon footprint. As an alternative, eggshell powder (ESP), rich in calcium, is proposed as a stabilizing agent. Soil properties were tested in accordance with ASTM standards. Consistent with Lee and Suedkamp, high-plasticity soil shows no distinct optimum dry density, making it difficult to establish a clear pattern of changes in this property. ESP addition reduces the Atterberg limits and Methylene Blue Value, lowers the swelling potential, and increases the unconfined compressive strength (UCS). The calcium content in ESP decreases the soil’s capacity to swell, although the effect appears limited due to remaining organic components. A significant improvement in UCS was observed with 5% ESP at 14 days of curing, increasing strength from 181.87 kPa to 327.49 kPa, while the most notable reduction in swelling potential occurred with 15% ESP at 7 days of curing. However, both UCS and swelling potential showed no consistent trend, likely due to complex interactions of organic materials in ESP that reduce its effectiveness in soil stabilization.

Adaptive Real-Time Strain-Rate Control in CRS Consolidation Testing Using SARSA Reinforcement Learning Muhammad Fadhl 'Abbas; Hasbullah Nawir; Dimitri Mahayana; Erza Rismantojo; Dayu Apoji; M. Alifsyah Putra Nasution; Targhib Ibrahim
Civil Engineering Journal Vol. 12 No. 4 (2026): April
Publisher : Salehan Institute of Higher Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28991/CEJ-2026-012-04-023

This study presents a reinforcement-learning framework for real-time strain-rate control in Constant Rate of Strain (CRS) consolidation testing to hasten the testing process using the SARSA algorithm. The controller adaptively adjusts deformation rate based on evolving pore-pressure ratio, with a reward strategy designed to maintain an average pore-pressure ratio near 30% to ensure partially drained conditions consistent with CRS theory. Two normally consolidated clays with contrasting compressibility were modeled numerically using a 1-D CRS consolidation model to evaluate learning and testing performance. The results show that the SARSA agent autonomously learns soil-specific strain-rate policies and maintains smooth effective stress trajectories and stable pore-pressure ratio responses. Test duration reductions of 60-75% were achieved depending on soil type. The interpreted compression index (Cc) remains consistent with the baseline CRS values, confirming that reinforcement-learning-based strain-rate control can accelerate testing without compromising data integrity. The study demonstrates the feasibility of reinforcement learning for CRS testing and highlights practical potential for soil-responsive, adaptive strain-rate control. Current limitations include simulation-based evaluation, discretized action selection, and the need for multiple runs to achieve optimal convergence.

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