Stabilization Of Subgrade Soils Research Articles

Design of sustainable bituminous concrete pavement with cement–treated granular layers constructed on stabilized subgrade

Purpose Designing a sustainable bituminous concrete with long-term performance is a challenging problem. In addition, strength of the subgrade has a crucial impact on pavement design. This paper aims to concentrate on subgrade soil stabilization with granite dust powder (GDP) and crumb rubber powder (CRP) to improve the engineering properties of the soil. Further design of bituminous concrete pavement with cement-treated layers in base and subbase course layers was carried out with life cycle cost analysis and life cycle assessment for 1 km of a four-lane national highway. Design/methodology/approach Subgrade soil stabilized with GDP and CRP is characterized as per Indian Standards (IS)-2720 to determine the optimum dosage. Further, the mechanistic-empirical pavement design was carried out using Indian Road Congress-37 (2018), analyzed using IITPAVE software and validated with ANSYS software. The life cycle cost analysis is carried out using the net present value method, and the life cycle assessment is performed according to the cradle-to-grave approach. Findings A soil mix comprising 10% GDP and 2.5% CRP yielded a soaked California bearing ratio value of 6.58%. In addition, the design of bituminous concrete pavement with cement-treated granular layers showed a 26.9% reduction in life cycle cost and 59.4% reduction in total carbon footprint per kilometer compared to the pavement with traditional aggregate layers. Originality/value The research on subgrade stabilization with sustainable materials like GDP and CRP incorporating mechanistic empirical pavement design, life cycle cost analysis and life cycle assessment is limited. Overall, the study recommends the use of GDP and CRP to stabilize soil for subgrade application and incorporate cement-treated granular layers, which offer economic and environmental benefits compared to traditional pavement construction.

Influence of Cementitious Stabilization of Subgrade Soil on the Distresses of Flexible Pavement Sections

Influence of Cementitious Stabilization of Subgrade Soil on the Distresses of Flexible Pavement Sections

Feasibility of using building-related construction and demolition waste-derived geopolymer for subgrade soil stabilization

A high-value utilization approach is essential to improve the utilization rate of building-related construction and demolition waste (brCDW). This study developed a novel approach by synthesizing a brCDW-derived geopolymer to stabilize high liquid limit subgrade soil. The unconfined compressive strength (UCS) test, shear strength test, resilient modulus test, and permanent strain test were conducted to investigate the effects of brCDW-derived geopolymer dosage, curing time, stress state, and moisture condition on the engineering properties of geopolymer stabilized soil. These test results demonstrated that increasing the geopolymer dosage effectively improved the UCS, shear strength and resilient modulus of stabilized soil and reduced the permanent strain of stabilized soil. The 8% brCDW-derived geopolymer provided adequate UCS, shear strength, resilient modulus, and resistance to permanent strain for stabilized soil, which showed the most economical improvement. Mechanistic-empirical models were employed to accurately estimate the stress-dependent resilient modulus and permanent strain of geopolymer stabilized soil at any given stress state. The Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) test were performed to investigate the strengthening mechanism of brCDW-derived geopolymer stabilization of subgrade soil. The SEM test results indicated that the porosity of stabilized soil was significantly decreased when the geopolymer dosage increased to 8%. The EDS test results demonstrated that the predominant gel types generated from the geopolymer stabilization might be Calcium–Aluminum-Silicate-Hydrate (C-A-S-H), Calcium-Silicate-Hydrate (C–S–H), and Calcium-Aluminate-Hydrate (C-A-H) gels. There was also a small amount of Sodium-Alumino-Silicate-Hydrate (N-A-S-H) gel detected in the geopolymer stabilized soil. Finally, the sustainability of brCDW-derived geopolymer stabilization approach was assessed in terms of material production cost, carbon dioxide emission, and energy consumption. The brCDW-derived geopolymer was proven as a sustainable stabilizer for subgrade soil.

CONSTRUCTION OF SUSTAINABLE ROADS USING THE MIXTURE OF ALKALI-ACTIVATED RICE HUSK ASH AND FLY ASH

Soil stabilization, crucial for enhancing the stability and engineering properties of soil, has been the subject of extensive research utilizing mechanical and chemical methods. This study delves into the challenges faced in traditional soil subgrade stabilization methods, stemming from factors such as soil erosion, inadequate load-bearing capacity, and susceptibility to environmental conditions. These challenges have prompted the exploration of innovative solutions for road subgrade soil stabilization. Our primary motivation stems from the limitations of conventional techniques and the pressing need to address issues like resource exploitation and environmental pollution. Geopolymers, specifically alkaline-activated materials, have emerged as a promising alternative for soil stabilization. This research investigates the effects of geopolymer blended with rice husk ash (RHA) and fly ash (FA) on various geotechnical properties of natural and admixed black cotton soil. The soil is replaced with admixtures ranging from 0% to 30% of blended geopolymer by weight. The study provides a comprehensive analysis, focusing on quantifiable improvements in soil properties through numerical results. The investigations consistently reveal that the application of geopolymer as a soil stabilizer results in notable improvements in the geotechnical properties like index properties, strength properties, resistance to penetration (CBR), etc., of problematic soil. Comparative analysis with traditional methods underscores the superiority of the proposed geopolymer blend, showcasing its innovation, sustainability, and cost-effectiveness. The findings of this study contribute to the advancement of soil stabilization techniques, specifically in the context of geopolymer applications. For future work, this study suggests an in-depth exploration of geopolymer-stabilized soil's long-term durability and environmental impact. Additionally, further research could focus on optimizing the geopolymer blend ratios for varying soil types and environmental conditions.

Subgrade soil stabilization using the Quicklime: a case study from Modjo- Hawassa highway, Central Ethiopia

This study examined the index properties, strength, and swelling pressure by mixing the Quicklime with five soil samples taken from the Meki-Abossa road section part of the Modjo- Hawassa highway. The main goal of this study was to provide more insight into the effects of Quicklime stabilization on the Atterberg limit like (LL, LP, and PI), OMC, MDD, CBR, and CBR swell percent of subgrade soil along the selected route alignment. Five disturbed samples were collected from the Meki-Abossa Road section to achieve the objectives. The samples were collected using the open pit sampling method with an average 1-1.5 m depth. Laboratory works were carried out for natural sub-grade soil and soil mixed with Quicklime. The natural sub-grade soil was classed as A-7-5 (38) by AASHTO and MH & CH by USCS, with a maximum LL of 75, PI of 41.6, MDD of 1.59, and OMC of 28, with CBR values less than five and CBR swell > 2%. The recommended lime (4%, 6%, and 8%) was mixed with the subgrade material. The result shows that the soil treated with Quicklime 4%, 6%, and 8% improved or lowered the untreated expansive soil plasticity index by 18.5%, 28.9%, and 23.8%, respectively, and increased OMC by 15.2% and reduced MDD by 18.23%. On the other hand, CBR values of the treated soil were increased by an average of 56.9%, with lower swelling potential decreases by 93.3%, higher workability, and stabilized soils were feasible to be used as subgrade material.

NSF (Nylon Synthetic Fiber) Effectiveness in Stabilizing Weak Subgrade Soil: An Experimental Investigation

Improvement in subgrade soil has always been an area of concern for highway and geotechnical engineers. Weak subgrade soil results in a greater thickness of the pavement layer, which increases the cost of pavement construction. It further leads to large deformations, which in turn cause continuous deterioration of the paved surface. To solve this problem, various engineering solutions and soil improvement mechanisms were previously proposed. This study was designed to investigate the stabilization of weak subgrade soil with nylon synthetic fiber (NSF) in a compromising combination. Previously, some investigations used a lower fiber content with a higher fiber length, whereas others used a lower fiber length with a higher fiber content. However, this investigation was uniquely designed to stabilize weak subgrade soil with the consideration of appropriate fiber length (10 mm and 20 mm) and content (0.5%, 1%, 1.5%, and 2.5%). The engineering properties of the soil, the effect of NSF on weak subgrade soil, various fiber content and aspect ratios, and the optimum content and critical fiber aspect ratio were investigated in a laboratory. The effect of fibers on compaction, CBR values, and CBR swell values has also been studied. Laboratory results on the modified compaction tests showed that maximum dry density (MDD) was increased with the increment of fiber content, whereas optimum moisture content (OMC) remained constant. The soaked CBR and CBR swell values of natural soil were 1.80% and 8.95%, respectively. Due to reinforcement, the percentage increase in soaked CBR value at the optimum NSF content is 265.3, 310.0, 282.8, and 342.2 for aspect ratios of 33.33, 66.67, 25, and 50, respectively, with reference to natural soil. Also, the percentage decrease in swelling is 34.7, 52.75, 43.55, and 36.9, respectively. Moreover, the CBR value increases with the increase in aspect ratio by keeping the diameter constant and decreases with the increase in aspect ratio by keeping the length constant. It was also observed that increasing the length and diameter of NSF further increased the CBR value of reinforced soil. This increment was substantial at a fiber content of 1.5% for an aspect ratio of 50 (length = 20 mm, diameter = 0.4 mm). There was also a decrease in the CBR swelling value with an increase in fiber content. Finally, this investigation concluded that the use of NSF is a solution to weak soils with regard to moisture and performance problems.

Subgrade soil stabilization using geosynthetics: A critical review

The construction of roads has been highly impacted due to weak subgrade. During the design phase of road, the index properties and various investigations required to check the strength of subgrade. In different types of soil subgrade, subjected to its weak strength, various types of stabilization have been performing throughout the world. Geosynthetic materials are now a days become a research interest for stabilization of weak soil. It acts as reenforcing agent in soil subgrade. Geotextiles, geogrids, steel fibers, etc. are some types of geosynthetics which helps to distribute the loads on pavement structure more efficiently. According to studies, it improves the soil subgrade's effective bearing capacity and serves as an alternate method of economic stability. Geotextile may also be used as reinforcement in asphalt overlays to mitigate the reflection cracking. Geotextiles also aid in enhancing the base course's flexural stiffness, which lowers the maximum vertical load on the subgrade. The stability of subgrade soil under the effect of geosynthetic materials contributes to an increase in bearing capacity.

Multiwalled Carbon Nanotube Aided Fly Ash-Based Subgrade Soil Stabilization for Low-Volume Rural Roads

Multiwalled Carbon Nanotube Aided Fly Ash-Based Subgrade Soil Stabilization for Low-Volume Rural Roads

Stabilization of calcareous subgrade soils with polyelectrolytes: mechanisms and mechanical properties

ABSTRACT Organic polyelectrolytes, i.e. anionic poly(sodium 4-styrenesulphonate) (PSS), cationic poly(diallyldimethylammonium chloride) (PDADMAC) and their polyelectrolyte complexes (PECs) were evaluated for stabilisation of calcareous sandy subgrade soil. This paper investigated the effects of polymer type, surface charge type of PEC, concentrations of PEC solutions and dosages of polymer solutions added to the soil on improvement of soil mechanical properties. We found that anionic polymers, for both PECs and individual polyelectrolytes, were superior to their cationic counterparts in improving soil strength. Besides, the constituent polyelectrolytes, PSS and PDADMAC, worked better than their PECs for the specific soil investigated. The strength of polymer-treated soils was also found to increase with the increase in dosages of the polymer solutions as well as curing periods. Furthermore, polymer-treated soil specimens exhibited significant toughness improvement, which was higher than cement-treated samples. Scanning electron microscopy images revealed the abundance of long palygorskite fibres covering the surfaces of larger calcite and dolomite particles and linking surrounding aggregates after adding polymers. This observation suggests the interconnection of palygorskite fibres and their linking networks between and among coarse aggregates as the likely mechanism of polymer stabilisation of the soil studied.

A review on subgrade soil stabilization using bio enzymes

A review on subgrade soil stabilization using bio enzymes

Sustainable Utilization of Calcium Carbide Residue along with Polypropylene Fiber Waste Materials for Accessing Swelling and Strength Characteristics of Black Cotton Soil

Due to industrialization and modernization, huge amount of waste generated by many industries causes a huge threat to the human health, environment and aqua life due to disposal problems. The present study focuses on utilizing industrial wastes to strengthen geotechnical properties of black cotton soil. The toxic compounds included in calcium carbide residue (CCR) created by the acetylene gas companies and polypropylene fiber made by the textile mills are both highly polluting. These materials can be utilized in soil stabilization alone and in combination in various proportions to obtain the finest subgrade material. The use of such industrial waste for subgrade soil stabilization is a cost-effective way of building pavements. This study examines the effects of addition of different percentages of CCR and fiber contents on Atterberg’s limits, compaction characteristics, unconfined compressive strength and California bearing ratio.

Sustainable Application of Wool-Banana Bio-Composite Waste Material in Geotechnical Engineering for Enhancement of Elastoplastic Strain and Resilience of Subgrade Expansive Clays

Agro-biogenic stabilization of expansive subgrade soils is trending to achieve cost-effective and sustainable geotechnical design to resist distress and settlement during the application of heavy traffic loads. This research presents optimized remediation of expansive clay by addition of proportionate quantities of waste renewable wool-banana (WB) fiber composites for the enhancement of elastoplastic strain (ԐEP), peak strength (Sp), resilient modulus (MR) and California bearing ratio (CBR) of expansive clays. Remolded samples of stabilized and nontreated clay prepared at maximum dry density (γdmax) and optimum moisture content (OMC) were subjected to a series of swell potential, unconfined compressive strength (UCS), resilient modulus (MR) and CBR tests to evaluate swell potential, ԐEP, MR, and CBR parameters. The outcome of this study clearly demonstrates that the optimal WB fiber dosage (i.e., 0.6% wool and 1.2% banana fibers of dry weight of clay) lowers the free swell up to 58% and presents an enhancement of 3.5, 2.7, 3.0 and 4.5-times of ԐEPT, Sp, MR and CBR, respectively. Enhancement in ԐEP is vital for the mitigation of excessive cracking in expansive clays for sustainable subgrades. The ratio of strain relating to the peak strength (ԐPS) to the strain relating to the residual strength (ԐRS), i.e., ԐPS/ԐRS = 2.99 which is highest among all fiber-clay blend depicting the highly ductile clay-fiber mixture. Cost-strength analysis reveals the optimized enhancement of ԐEPT, Sp, MR and CBR in comparison with cost using clay plus 0.6% wool plus 1.2% banana fibers blend which depicts the potential application of this research to economize the stabilization of subgrade clay to achieve green and biogeotechnical engineering goals.

Subgrade soil stabilization using marine debris: A literature review

The use of different marine residues found in the great biodiversity of the Peruvian coast, such as crushed mollusk shells or fan shells, can be used as mechanical stabilizers for clay soils due to a change in granulometry. In this article, we reviewed 74 research studies indexed in different databases such as Scopus, Scielo, Ebsco, Proquest, Springer Link, and ScienceDirect, whose publication has not exceeded seven years, with the objective of carrying out a systematic review of the use, effect and influence of marine debris as soil stabilizers. For this purpose, the analyses of the mechanical and also physical properties of such mixtures in different marine debris were reviewed compared to the various types of stabilizers currently used. These evaluated results indicate, that the Pacific razor clam shell offers a lower bearing capacity compared to the fan shell when stabilizing clayey soil. However, the shredded output of both types of marine debris can meet the need for clay subgrade stabilization. Based on the review, it was determined that the addition of different types of shredded marine debris reduces water absorption by capillarity, increasing the resistance and bearing capacity of the soil.

Application of eco-friendly and smart materials in geotechnical engineering for subgrade stabilization: a review

The performance of road pavement mainly depends upon the properties of subgrade soil. The failures occur in case of road pavement is due to poor strength characteristics and high volume change behaviour of subgrade soil. Thus, considering the performance criteria, subgrade soil needs to be treated so as to make it suitable for the construction of road pavement. It was observed that, soil stabilization using various admixtures is more effective and commonly used practice for enhancing the properties of subgrade soil. The previous research shows that subgrade soil stabilization can be achieved with the application of various environmental friendly (Bio – Enzymes) and smart materials (Agricultural and Industrial waste) in required quantity to enhance the physical, strength and volume change characteristics of natural soil. It was also observed that, the combined use of such materials makes the subgrade soil more suitable for the construction of road pavement. From the experimental investigations of various available research works on subgrade stabilization, it was observed that strength and volume change properties such as California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS) and Swell Pressure of subgrade soil can be effectively changed with the help of use of such materials. It was also observed that use of conventional methods has negative impact on environment. Thus, subgrade can be stabilized with eco – friendly and cost effective materials to achieve both economic and serviceability criteria.

Effects of Solid Beer Factory Waste as a Partial Replacement of Gypsum for Stabilization of Weak Subgrade Soil

Effects of Solid Beer Factory Waste as a Partial Replacement of Gypsum for Stabilization of Weak Subgrade Soil

Investigation on use of silica based additive for sustainable subgrade construction

This study presents the potential application of cement and StabilRoad, a silica based additive for subgrade soil stabilization. The coupling effect of soil, cement and StabilRoad additive has been evaluated by compaction characteristics, California bearing ratio (CBR) and Unconfined compressive strength (UCS) at various percentages of cement along with this additive. The underlying mechanism that contributes to the stabilization process was visualized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result indicates an enhancement in mechanical performances of the soil mixture containing this additive. CBR value and UCS were increased by 72.413 % (soaked condition) and 79.16 % (28 days) on addition of 1 % StabilRoad to the cement modified soil mixture. Meanwhile, different regression models namely, quantile regression (QR), partial least square regression (PSL-R), and linear regression (LNR) models have been developed to establish the relationship of UCS and CBR with routine properties of subgrade soil. LNR model attained the highest predictive accuracy in all cases. An increase in the intensity of C-S-H peaks has been observed with the incorporation of this additive which is responsible for enhanced strength in the modified soil mixture. Subgrade stabilization with this additive also resulted in reducing the overall cost by minimizing the crust thickness of the pavement. Therefore, the present investigation confirms the usability of cement and StabilRoad in subgrade stabilization with significant economic benefits.

Impacts of Lightweight Aggregate Interlayers for Air Convection Embankment on Pavement Thermal Profile and Pavement Performance in Alaskan Permafrost Regions

Crushed-rock air convection embankment (ACE) has been used to mitigate pavement distresses caused by climatic extremes in permafrost regions for more than three decades. This study proposes using lightweight aggregates as cost-effective alternative materials to overcome the shortage of desired crushed rocks needed for ACE in interior Alaska. This paper presents an investigation of the performance of six selected pavement structures: an asphalt pavement typical of the northern region of Alaska and five pavements reinforced with different paving interlayers (i.e., silty sand/gravel, crushed rocks, cellular concrete aggregate, foam glass aggregate, and lightweight expanded clay aggregate). Pavement thermal analyses using Temperature Estimate Model for Pavement Structures (TEMPS) program and ANSYS Fluent software were performed to predict heat transfer patterns and thermal performance for each case. Pavement performance analyses using viscoelastic-based FlexPAVE™ and the elastic-based Alaska Flexible Pavement Design (AKFPD) program were conducted to evaluate the long-term performance and structural stability of subgrade soil with different types of interlayers. The results showed that the lightweight aggregate ACEs improved cooling performance more effectively than the crushed-rock ACE. The lightweight aggregate interlayers could maintain desired thermal insulation in summer and enhance the cooling effect in winter. The modeling results identified the high potential of using lightweight aggregates as alternative ACE materials to improve pavement service life and subgrade stability.

Evaluation of Geopolymer for Stabilization of Sulfate-Rich Expansive Soils for Supporting Pavement Infrastructure

Stabilization of sulfate-rich expansive subgrade soils is a persistent cause of concern for transportation infrastructure engineers and practitioners. The application of traditional calcium-based stabilizers is generally not recommended for treating such soils because of the formation of deleterious reaction products such as ettringite. Sulfate-induced heaving causes severe structural damage to pavements and accounts for enormous expenditure from routine maintenance and rehabilitation activities. A research study was undertaken to evaluate the feasibility of using a metakaolin-based geopolymer (GP) for the treatment of sulfate-rich expansive soil. Laboratory studies were conducted on natural soil and artificially sulfate-rich soils, when treated with either lime or GP, to evaluate and compare the improvements in the engineering properties, including unconfined compressive strength, swelling and shrinkage, and resilient moduli characteristics over different curing periods. Microstructural studies, such as field emission scanning electron microscopy and X-ray diffraction, were performed on treated soils to detect the formation of reaction products. The engineering studies indicate that GP treatment enhanced strength and resilient moduli while suppressing ettringite formation and the associated swell–shrink potential of the treated soils. The microstructural studies showed that GP gels contribute to the improvement of these engineering properties through the formation of a uniform geopolymer matrix. In addition, the absence of a calcium source suppressed the formation of ettringite in the GP-treated soils. Overall, the findings indicate that GPs could be used as a potential alternative to existing traditional stabilizers for treating sulfate-rich expansive soils.

Suitability Assessment of Using Lime Sludge for Subgrade Soil Stabilization

Although several studies have been conducted regarding the use of lime sludge (LS) in engineering and agricultural applications, its use for stabilizing subgrade soils has not been fully investigated. In this study, an effort was made to evaluate the suitability of using LS alone or in combination with traditional stabilizers [fly ash and portland cement (PC)] to stabilize a frost-susceptible loess soil (LOE). A series of unconfined compression (UC), pH, and freeze-thaw (F-T) tests, as well as scanning electron microscopy (SEM), were performed for the evaluation. Test results indicated that using LS alone effectively improved the unconfined compressive strength (UCS) of the soil. In addition, using LS in combination with fly ash yielded further improvements in the UCS of the soil compared with using only fly ash for stabilization. Alternatively, using LS in combination with PC improved the UCS of the soil to a lesser extent than using PC alone for stabilization. In all the cases, the presence of LS in the soil matrix reduced the F-T durability.

Experimental investigation on stabilization of subgrade soil using bio-enzymatic additive for pavement construction

Experimental investigation on stabilization of subgrade soil using bio-enzymatic additive for pavement construction