California Bearing Ratio Research Papers (original) (raw)

2025, Materials

The utilization of industrial by-products as stabilizers is gaining attention from the sustainability perspective. Along these lines, granite sand (GS) and calcium lignosulfonate (CLS) are used as alternatives to traditional stabilizers for cohesive soil (clay). The unsoaked California Bearing Ratio (CBR) was taken as a performance indicator (as a subgrade material for low-volume roads). A series of tests were performed by varying the dosages of GS (30%, 40%, and 50%) and CLS (0.5%, 1%, 1.5%, and 2%) for different curing periods (0, 7, and 28 days). This study revealed that the optimal dosages of granite sand (GS) are 35%, 34%, 33%, and 32% for dosages of calcium lignosulfonate (CLS) of 0.5%, 1.0%, 1.5%, and 2.0%, respectively. These values are needed to maintain a reliability index greater than or equal to 3.0 when the coefficient of variation (COV) of the minimum specified value of the CBR is 20% for a 28-day curing period. The proposed RBDO (reliability-based design optimization)...

2025, Geological Behavior

Incessant road failures in Nigeria have become an issue of serious concern in recent times as a large portion of states and federal budgets are dedicated to revamping road infrastructures. In this study, we examined the geotechnical properties of clay samples collected from Ntak Inyang along Calabar-Itu highway, in Itu LGA of Akwa Ibom State, Nigeria with the aim of ascertaining whether the earth material at the study location is suitable for road construction. We carried out proctor’s compaction test, sieve analysis, California bearing ratio test and Attenberg’s limit test to analyse the clay samples for moisture content, California bearing ratio, plasticity and plastic limit, dry density and particle sizes. Results obtained indicate that the clay sample has an optimum moisture content of 13.53 %, dry density value in the range: 1580 kgm-3-1650 kgm-3, plastic limit of 22.15 %, plasticity index of 23 %, liquid limit of 45.63 %, sieve of 43.36 % with particles less than 0.075 mm and ...

2025, Tikrit Journal of Pure Science

The geotechnical, engineering and chemical properties of the sediments of river terraces on the right bank and flood plain on the left bank of Tigris river. The physical tests include (specific gravity, absorption%, moisture content %, atterberge limits, grain size analysis) showed that the dominant component of soil is (gravel) with varied amount of fine components, the engineering tests include direct shear test, CBR, and point load test, while the chemical analyses include gypsum%, T.D.S% and O.M% showed increase in gypsum% and T.S.S% in right bank and increase of O.M%, and decrease of the three ratios in the left bank because the leaching of the sediments. The geotechnical study showed many engineering problems occurs in engineering establishments specially in the river terraces because the high ratios of gypsum and T.S.S. http://dx.doi.org/10.25130/tjps.24.2019.110

2025, Applied Sciences

The application of new materials for soil stabilisation is a growing field of study in recent years. In this work, the effect of two types of silica-based nanomaterials combined with binders (quicklime and cement) are studied to stabilise soils and form structural layers for rural and low volume roads. The physical and chemical properties of the materials have been determined, as well as the mechanical behaviour of the stabilised soil. Three hybrid stabilised soil sections have been designed using a multilayer elastic model, executed at full scale and measuring the evolution of their properties in the medium to short term. The results show that the application of silica-based nanomaterials and two types of binders on the tread layers provide high structural stability and good behaviour of the sections.

2025, International journal of GEOMATE : geotechnique, construction materials and environment

Deep Soil Mixing (DSM) is a ground modification technique to improve soil characteristic. This paper explain the result of laboratory experiment of deep soil mixing (DSM) in small scale. The model have been constructed to estimate field condition. The important properties of expansive soil such as the strength and swelling were investigated. The fly ash was used as binder material to enhance strength and mitigate swell potential. However optimum binder dosage, water -binder ratio and geometrical column (length, diameter and spacing) influenced performance of DSM. Variation of length and spacing of column could be established by considering active zone and the area ratio in the single square arrangement. The required treatment area are determined based on tolerable swelling and allowable bearing capacity. The small scale of DSM construction showed significant improvement of swell and strength properties compare with untreated soil. The empirical model are presented in this research provided reasonable predictions of strength and swelling for in situ condition.

2025, Sustainability

Mining industries around the world produce massive amounts of solid waste that has potential environmental impacts. Therefore, it is necessary to explore alternative solutions to this waste disposal problem and to obtain economic benefits from it. Up to now, no significant attempts have been made to use granite dust (GD) as a soil stabilizer. GD is a by-product produced in large amounts during the cutting and processing of granite rocks at manufacturing factories. Thus, an attempt has been made here to define the role of GD in enhancing the geotechnical behaviour of expansive soil in order to make it suitable for construction. Moreover, the aim of this study is to evaluate the micro-level alterations occurring in the soil to elucidate the stabilization mechanism of granite dust–soil interaction. Comprehensive geotechnical tests, such as Atterberg limits, compaction characteristics, unconfined compressive strength (UCS), California bearing ratio (CBR), and swelling percentage, as wel...

2025, Sakarya University Journal of Science

Geotechnical investigations are one of the most crucial parts of the construction to save the time and effort spent on the projects. Particularly, in the case of the clays with high plasticity are encountered, the analysis of bearing capacity and settlement of structures such as buildings, roads, and dams governs the design. The possible solutions can be leaving the land, reaching a strong soil bypassing the weak one, removing the weak soil by replacing it with a higher strength of the material, and applying soil improvement methods. Glass fibers are one of the synthetic additives which may be used to address improving the weak soil properties. In this study, the effect of alkaline-resistant glass fiber additive on the undrained shear strength of the clayey soils was investigated. Fibers with distinct lengths were added to the natural soil at increasing rates, and the mixtures were prepared in the optimum water content. The prepared mixtures were compacted in a compaction mold with ...

2025, Civil Engineering Journal

Expansive clays can cause major problems for urban development (roads, railways, infrastructure, etc.); therefore, reducing the swelling potential of clays has always been a concern in the geotechnical field. The presented paper investigates the effect of polypropylene reinforcement fibers on the swelling potential and shear strength of clay. The samples studied were taken from the clayey region of Mila, located in the northern east of Algeria. The experimental procedure adopted in this research consists first of the assessment of the physical, mechanical, and mineralogical characteristics of the soil samples without reinforcement. Then, swelling pressure, swelling rate, and swelling index are used to assess the swelling potential of these samples. After the reinforcement using a variety of polypropylene fiber concentrations (2 to 6% of the weight of the dry clay), the free swelling is clearly reduced. The optimum reinforcement rate in this case is 4%, in which the swelling was redu...

2025, Innovation in Engineering

In developing countries, crushed rocks are mainly used in road subbase and base courses for road construction. As a result of extremely high fuel prices and lengthy travel times, particularly from Mokepalin, which is 92 miles from Yangon, the exorbitant costs of crushed rock aggregates for road building in Myanmar have therefore become a major concern. Due to energy consumption and carbon emissions, this dependence on remote sources results in increased building costs, project delays, and environmental destruction. In Yangon, local marginal materials (lateritic soil) are also available in Hmawbi, Hlegu, Taikkyi and Twantay townships. According to the engineering properties of soil in term of CBR, Hmawbi lateritic soil is nearly the same as the Mokepalin. Therefore, lateritic soil from Hmawbi was selected as a case study material for this research in order to reduce costs and to be more economical. To evaluate the engineering properties of soil, laboratory tests including sieve analysis, Atterberg limits, UCS, compaction, and CBR testing were carried out. The purpose of this paper is to stabilize lateritic soils for possible use as materials for road sub base and base to substitute crushed rocks. Results showed that 2% of cement and lime content met subbase course for Unconfined Compressive Strength (UCS) values of 0.75 MPa and 1.75 MPa according to Joint Departments of the Army and Air Force and 16% of cement satisfied for road base course for UCS value of 5.36 MPa. The use soil lime mixture was found to be unsuitable for road base course. Cement stabilized lateritic soil proved to be stronger, durable and better than soil lime mixture for road construction.

2025, International Journal of Scientific & Engineering Research Volume 10, Issue 8,

Twelve samples were collected from different locations in Anambra State for evaluation as base material for road construction. The samples were tested for specific gravity, particle size distribution, atteberg limit, linear shrinkage, compaction and california bearing capacity. The result of the specific gravity test ranges from 2.35Mg/m 3-2.63Mg/m 3 while the values of the particle size distribution test ranges from 13% and 36% making only sample S8 unsuitable for use as base material. The samples revealed the following range of values for atterberg limit properties: Liquid Limit 22% to 44%; Plastic Limit 10% to23%; Plasticity Index 12% to 24%; Linear Shrinkage 7% to 11%. AASHTO soil classification system identified S8 as A-7(poor), S9 and S12 as A-2-7 (good) while others are A-2-6(good) samples. M.D.D values obtained from compaction parameters range from 1.96 Mg/m 3 to 2.24 Mg/m 3 and O.M.C as 7.44% to 14.67% while the California Bearing Ratio (unsoaked) ranges from 76% to 113%. Based on the Nigerian Federal Ministry of Works and Housing specification (NFMWH), samples S1, S6 and S8 are only suitable for sub-base while samples S2, S3, S4, S5, S7, S9, S10, S11 and S12 are suitable for both sub-base and base-course. However, samples S1, S6 and S8 can be improved with stabilizers for use as base-course materials.

2025

Growing concern over the combustion cost and environment has made road engineers and scientists to explore the possible use of locally available materials for the construction of roads. The present study evaluated the strength and durability characteristics of five sites having locally available silty soils using lime and cement-sand stabilization technique. The test results showed that the cement-sand stabilization technique using 6% cement and 5% local sand resulted in higher strength and durability as compared to lime stabilization. There is also a significant increase in the value of the soaked California bearing ratio (CBR). As unconfined compressive strength (UCS) attained the threshold strength as prescribed by IRC SP 72 2015 for the granular sub-base (GSB) layer, by the use of sand cement stabilization, this technique of stabilization for local silty soils could be used for GSB for low volume road (LVR) construction. As observed from microstructural results which were performed by analysing SEM images, sand cement stabilisation leads to CSH gel and agglomerate formation thereby increasing strength and durability properties. The cost analysis for the replaced stabilized GSB layer showed that using sandcement stabilization, the estimated cost can be reduced by 56% of the total cost as compared to the conventional method.

2025, Jordan Journal of Civil Engineering

Globally, most of the factories have some waste that can be regularly produced. Cement factories generate cement kiln dust (CKD) waste, releasing large plumes into the air. Accumulation of factory waste, such as CKD, is a serious issue that has been considered in much research for some time to find the best cost-effective methods to utilize CKD for various purposes in construction projects. In this study, clay soil (CL) that covers most of north Iraq is considered to characterize its geotechnical characteristics in the in-situ condition and as a soil-CKD mixture. CKD was utilized with percentages of 10%, 20%, 30%, and 40% as an additive to replace the dry mass of the in-situ soil sample. The study's experimental program involves conducting geotechnical experiments to determine compression index, expansion index, standard proctor compaction, compressibility, and hydraulic conductivity. CKD improved the compaction characteristics, increasing the maximum dry density (MDD) after adding 10% CKD, and the optimum moisture content (OMC) linearly rose. The reduction in the porosity value was noticed particularly after 20% addition of CKD. Compressibility parameters, compression index (Cc) and expansion index (Ce), settlement, and swelling were also enhanced for stabilization and their reductions were significantly noticed. CKD successfully reduced the hydraulic conductivity values of soil-CKD mixtures. The study indicates that CKD is a significant soil stabilizer, suggesting that its removal and use for soil stabilization could have positive environmental consequences.

2025, Applied Sciences

The California bearing ratio (CBR) test evaluates the structure of the layers of pavements. Such a test is laborious, time-consuming, and its results are generally affected by sample disturbance and tests conditions. The main objective of this research was to build a numerical model for the prediction of CBR tests that might substitute laboratory tests. The model was based on structural and physical parameters of granular bases. Four different materials from the central region (Querétaro) and north (Mexicali) of Mexico were used for the experimental work. Using the above-mentioned materials, 36 samples were fabricated, and six of them were used for the evaluation of the model presented in this research. Numerical and experimental comparisons demonstrated the adequacy of the model to predict the result of CBR tests from soil parameters.

2025, Acta Technica Jaurinensis

In this study, use of a new polypropylene geofiber type called microgrid fiber (MGF) was investigated in comparison with a conventional polypropylene fiber (PPF) product. Liquefaction resistances of saturated silty sand type soil mixes reinforced with different polypropylene type geofiber additives were investigated carrying out different laboratory scale cyclic load tests. Depending on the fiber content, liquefaction resistances of soil mixes were significantly improved using the geofiber additives. According to the results obtained from this study, the MGF type fiber increased the liquefaction resistances at higher rates in comparison with the conventional PPF product. It was assessed that MGF type novel additives can be used to supply a better adherence in soil mixes and higher reinforcement performances against the liquefaction, rather than conventional PPF products.

2025, Buildings

The increase in population has made it possible for better, more cost-effective vehicular services, which warrants good roadways. The sub-base that serves as a stress-transmitting media and distributes vehicle weight to resist shear and radial deformation is a critical component of the pavement structures. Developing novel techniques that can assess the sub-base soil's geotechnical characteristics and performance is an urgent need. Laterite soil abundantly available in the West Godavari area of India was employed for this research. Roads and highways construction takes a chunk of geotechnical investigation, particularly, California bearing ratio (CBR) of subgrade soils. Therefore, there is a need for intelligent tool to predict or analyze the CBR value without timeconsuming and cumbersome laboratory tests. An integrated extreme learning machine-cooperation search optimizer (ELM-CSO) approach is used herein to predict the CBR values. The correlation coefficient is utilized as cost functions of the CSO to identify the optimal activation weights of the ELM. The statistical measures are separately considered, and best solutions are reported in this article. Comparisons are provided with the standard ELM to show the superiorities of the proposed integrated approach to predict the CBR values. Further, the impact of each input variable is studied separately, and reduced models are proposed with limited and inadequate input data without loss of prediction accuracy. When 70% training and 30% testing data are applied, the ELM-CSO outperforms the CSO with Pearson correlation coefficient (R), coefficient of determination (R 2 ), and root mean square error (RMSE) values of 0.98, 0.97, and 0.84, respectively. Therefore, based on the prediction findings, the newly built ELM-CSO can be considered an alternative method for predicting real-time engineering issues, including the lateritic soil properties.

2025, Buildings

2025

NZ Transport Agency Research Report 628 that the New Zealand vibrating hammer compaction test procedure provides inconsistent results, with Repeatability and Reproducibility values of the New Zealand Standard for the vibrating hammer compaction test method being lower than those values found in standards both in America and the United Kingdom.
New Zealand pavements are predominantly (>90%) unbound granular aggregates, which fail primarily either in fatigue (shear), or consolidation (rutting). These types of aggregates and pavements rely heavily on reaching design compaction levels to be able to withstand their design life of repeated loading cycles. The desired compaction level is therefore extremely important to getting the expected design life out of the total pavement structure. As can therefore be expected, Quality Assurance of constructed road layers is also carried out primarily through the achievement of the design dry density in-situ at completion of compaction, commonly specified as a percentage of the Maximum Dry Density (MDD) for the material being used, such as in NZTA B/02:2005.
The most commonly used laboratory compaction methods around the world are the Standard or Modified Proctor tests. The Standard and Modified Proctor tests were established in the 1930s and 1950s, respectively, and have remained relatively unchanged since then. In the same time frame, field compaction has undergone major advances due to technological advances and equipment size and design. There have been many studies and research projects carried out internationally to try replicate these developments in field compaction, and laboratory test procedure changed over the years with this in mind.
New Zealand, to remain abreast of these developments, adopted the British vibratory hammer compaction method, with variations i.e. NZS 4402:1986 test 4.1.3 method which was considered a closer approximation of field compaction. Generally, in New Zealand, Maximum Dry Density is obtained in the laboratory following this test method. Furthermore, the same vibrating hammer compaction technique is also used to produce samples for several other pavement and geotechnical-related test methods including California bearing ratio (CBR), Indirect Tensile Strength (ITS), Unconfined Compressive Strength (UCS) and Repeated Load Tri-Axial Test (RLT).
As discussed earlier however, this test method demonstrates significant variability when testing the same sample with the same equipment by the same operator (poor repeatability) and when testing the same sample with different equipment and a different operator (poor reproducibility). This variability potentially leads to a number of issues including contractual and long-term performance issues as the laboratory density may be significantly higher or lower than that achievable in the field, and also makes retesting of a material problematic. Improved accuracy and consistency of sample compaction is therefore very important from a quality control perspective in terms of pavement testing, construction and performance.

2025, Malaysian journal of civil engineering

As a result of increase in population and socioeconomic activities, the rate of production of wastes over the years has been on the rise. A major approach towards managing these wastes is to consider the possibility of waste recycle and minimization. This study assesses the effects of Snail Shell Ash (SSA), a product of snail shell-which itself is a waste product, on lime stabilized lateritic soil. Preliminary tests such as; specific gravity, Atterberg limits and particle size distribution tests were carried out on natural soil sample, for the purposes of identification and classification. The soil sample based on AASHTO classification was classified as A-7-5. Hydrated lime was added to the soil sample at varying proportions of 2, 4, 6, 8 and 10% by weight of soil, thereafter, each of the mixes was subjected to Atterberg limits tests to get the optimal amount of lime required, which was 10% lime because it was at this amount of lime that the least value of plasticity index was gotten. The Snail Shell Ash was later added to the lime-treated lateritic soil at proportions of 2, 4, 6, 8 and 10%. Each of the mixes was subjected to compaction, California bearing ratio (CBR), Atterberg limits and unconfined compressive strength (UCS) tests. Results from these tests showed improvement in soil properties, also, the values of the CBR and UCS increased considerably. At soil natural states, CBR values of 9.5% and 5.5% increased to 67.20% and 53.60% at 6% SSA at unsoaked and soaked states respectively. Also, UCS value of 190 kN/m 2 at soil natural increased to 380kN/m 2 at 6% SSA. It can be concluded that the SSA performs satisfactorily as a cheap complement for lime in stabilizing lateritic soil.

2025, Journal of Engineering and Technology

This study assesses the effects of Guinea Corn Husk Ash (GCHA) on lime stabilized lateritic soil. Preliminary tests were carried out on natural soil sample, for the purposes of identification and classification. The soil sample was classified as A-7-5. Hydrated lime was added to the soil sample at varying proportions of 2, 4, 6, 8 and 10% by weight of soil, thereafter, each of the mixes was subjected to atterberg limits tests to get the optimal amount of lime required, which was 10% lime because it was at this amount of lime that the least value of plasticity index was obtained. The guinea corn husk ash was later added to the lime-treated lateritic soil at proportions of 2, 4, 6, 8 and 10%. Each of the mixes was subjected to compaction, California bearing ratio (CBR), atterberg limits and unconfined compressive strength (UCS) tests. Results from these tests showed improvement in soil properties, also, the values of the CBR and UCS increased considerably. It can be concluded that the GCHA performs satisfactorily as a cheap complement for lime in stabilizing lateritic soil.

2025, International Journal of Design & Nature and Ecodynamics

The roads in the city of Nasiriya in southern Iraq suffer from problems that occur as a result of repeated vehicle loads or due to weak soil and lead to losing their performance and being out of service despite their construction for a very short period. The use of chemical additives to improve the subgrade widely worldwide and give strength and durability to the weak soil while the possibility of using chemical additives for the substrate in Al-Nasiriya is still practically limited. The study aimed to verify the use of chemical additives (cement, lime, and ferric chloride) and to know their effect on the properties of Al-Nasiriya soil. The results showed a clear improvement in the UCS test when using chemical additives, and then the optimal percentages of additives were determined and were 9%, 10%, and 2% respectively, in addition to knowing the effect of the curing period (1, 7 and 14) days on the results of the test. For the other tests (maximum dry density, CBR, swelling, and op...

2025

The construction and maintenance costs of pavement are important aspects for road construction. The current research provides a newly technique for the use of jute fibre sheet as an interface layer between the subgrade soil and subbase layer which is limit in previous studies. The work involved comparison different locations for jute fibre sheet with the tradition approach of soil stabilization which imbedded the jute fibre sheet inside the subgrade soil. California Bearing Ratio (CBR) test was conducted on samples with jute fibre sheet, jute fibre sheet coated with bitumen and fibre only. Finite Element Models (FEM) using ABAQUS programme was implemented to show the effect of the new improvement on the vertical compressive strain at the top of subgrade and consequently rutting resistance. The experimental results showed a superior performance for the specimens containing bitumen coated jute fibre sheet placed at the interface between subbase and soil compared with unreinforced specimens (190 % penetration resistance). The bitumen coated jute fibre sheet also showed a significant increase in CBR value compared with traditional improvement of mixing or

2025, Civil Engineering Journal

Recently, geotechnical studies have been conducted more progressively to utilize dredged soil. The inclusion of shredded rubber (SR) and natural minerals (NM) to stabilize dredged soil (DS) has become an exciting issue in the geotechnical field. This technique can be a promising environmental innovation for the future. This study aimed to investigate the unconfined compressive strength (UCS), California bearing ratio (CBR), and embankment performance under the strip footing test. The UCS sample was prepared using shredded rubber with a proportion of 2% and 3% and natural minerals with a proportion of 3%, 6%, 9%, and 12% from the dry weight of the soil. Whereas for the CBR samples (both in un-soaked and soaked conditions) were also prepared with a proportion of 2% and 3% shredded rubber and 6% and 9% natural minerals from the dry weight of the soil as well. The strip footing test was conducted in small-scale laboratory tests to evaluate the performance of stabilized dredged soil emba...

2025

This standard is issued under the fixed designation D6241; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

2025

A global database of in situ soil test measurements and associated attributes was compiled for use in developing California bearing ratio (CBR) prediction models. From a variety of potential data sources, a collection of U.S. Army and Air Force airfield pavement research and evaluation reports was selected for inclusion. The schema includes data fields for common geotechnical parameters related to airfield pavement strength and geomorphological features associated with soil formation. More than 4,500 records from 46 test sites, representing 10 countries and 4 continents, were gathered and more than 1,500 of these contain field CBR test values. The database includes a wide variety of Unified Soil Classification System (USCS) soil types from a diversity of natural environments. The distribution of the numeric parameters in the database fall within the range of published distributions for natural soils reported in the literature. The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

2025, Discover Civil Engineering (Springer)

Road pavement requires a standard level of strength before it can be safely used to accommodate wheel loads. This strength can be achieved by compacting and stabilizing the soil with Portland cement. However, the environmental problem associated with its production has made researchers delve into substitute material. An investigation was conducted on the effectiveness of mango leaf waste ash (MLWA) in stabilizing compacted lateritic soil (CLS) for road pavement (RP). The various tests conducted on the LS and LS-MLWA in the laboratory include index properties, Atterberg limit, compaction characteristics (using British standard light energy), California bearing ratio (CBR), and unconfined compressive strength (UCS). The results were analysed using analysis of variance (ANOVA). The LS was treated with varying concentrations of MLWA up to 10% by soil dry weight. The compacted natural lateritic soils (LS) used in the study were categorized as A-7-6 (5) and CL under the America Association of State Highway Officer (AASHTO) and Unified Soil Classification System (USCS) classifications, respectively. The result of the atterberg limit indicated an improvement in the plasticity of the treated soil. The maximum dry density (MDD) value of the treated soil lessened with an increase in optimum moisture content (OMC). MLWA content of up to 6% resulted in an improvement in both the CBR and UCS values. However, UCS values of the cured for 7, 14 and 28 days fell short the TRRL road Note: 31 recommendation and Nigerian General Specification for Road and Bridges, which is 1710 kN/m 2. Analysis of variance (ANOVA) test results displayed that the Atterberg limits, compaction parameters, CBR, and UCS were statistically significant for the MLWA-LS mixture. The combination of LS and 6% MLWA produced an optimal mixture that significantly improved the soil's strength, making it suitable for use as sub-base material in roads with low to moderate traffic.

2025, International Journal of Progressive Sciences and Technologies

This study investigated the effect of rice husk ash (RHA) on the strength properties of cement stabilized lateritic soil. Geotechnical and chemical tests were used to characterize both the raw and treated laterite. Rice Husk Ash (RHA) was used in the present study as admixture. The compaction test, specific gravity, triaxial compressive strength test and California bearing ratio tests of the samples were carried out with varying proportions of RHA; 2%, 4%, 6%, 8% and 10%. The soil classification test showed that the soil is A-7-6 soil on the AASHTO soil classification system. The specific gravity test result showed that specific gravity of 2.70 was obtained. There was an increase in dry density from 1.325mg/m 3 at 0% to 2.3mg/m 3 at 10% RHA + 6% cement content. The CBR value increased from 11.00% in its natural state to 102.05% at 10% RHA + 6% cement content. The Triaxial compressive strength test showed that the frictional angle increased from 22° at 0% to 28° at 8% RHA and the test maintained a considerable cohesion with the varied percentage of RHA. Therefore, RHA has been proved to be a good admixture on the improvement of the engineering properties of lateritic soil for road construction.

2025

A nation's development depends on the transportation of goods and services via roads. Subgrade properties control the structural design of road pavement systems. Poor subgrade soil conditions can result in inadequate pavement support and reduced pavement life. In the subgrade construction of roads, the use of all natural materials is largely unavoidable due to technical, economic and environmental considerations. As a result, identifying and treating poor soils is one of the most important objectives. Soil stabilization can be used to improve the quality of subgrade soil materials. Stabilization can be achieved through different techniques such as compaction, chemical stabilization, and mechanical stabilization. These techniques are used to improve the load bearing capacity of soil and reduce the shrink-swell potential. This ensures a stronger foundation and better performance of the pavement. In the past conventional materials such as Portland cement and bitumen were used as additives to improve qualities of subgrade soil. However, due to the cost and environmental concerns, more eco-friendly and cost-effective materials such as lime and fly ash are being used as alternatives. These materials also have the same stabilizing effects as conventional materials. These materials not only reduce the cost of construction but also reduce the environmental impact. This makes them a great alternative for stabilizing subgrade soil and improving pavement performance. However, increase in the cost of these materials in recent times has led to some construction companies avoiding their use and a search for other alternatives. The LL, PL, LS and PI were 48.0, 16.5, 9.0 and 31.5%, respectively for laterite soil with lime while its LL, PL, LS and PI were 48.0, 17.5, 9.0 and 30.5% respectively for laterite soil with CKD, it has been found to be advantageous over some other stabilizers, due to its effectiveness in improving soils strength, minimizing work time and cost. Therefore, research into the other alternatives has been undertaken, such as geosynthetic materials, which have been found to be a promising solution. Geosynthetics are also cheaper and require less maintenance than conventional materials. Lime is utilized as an effective way of modifying subgrade soil conditions, thereby improving both workability and load-bearing characteristics while increasing stability and impermeability. Geosynthetic materials are also more environmentally sustainable than conventional materials, making them a preferred option for many projects.

2025

2025, Advances in Civil Engineering

Black cotton soils, which are expansive, are present in abundance in Ethiopia. This type of soil possesses expansion when saturated with water and contraction during hot seasons, due to which it is labelled as “weak soil.” They may remain a threat to the structures if they are constructed over them without precautions. The quality of such soils can be improved by treating them with suitable stabilizers or soil reinforcers. This paper discusses the chances of using the second waste of plastic bottles as a reinforcer to strengthen weak black cotton soils in Ethiopia. Second, plastic bottle waste was added at 1%, 2%, 3%, 5%, 7%, and 9% to the soil, and numerous trials were conducted to ensure the reliability of the results. The effects were analyzed based on the results from the Atterberg limit tests, compaction tests, unconfined compression strength (UCS) tests, and the California bearing ratio test (CBR) for soaked and unsoaked conditions. The results were compared against the natura...

2025, Materials and Structures

In many developing countries, where resources are at premium, thin asphalt layers or chip seals are widely used to provide a durable all weather pavement surfacing. In such pavements the role of granular layers is very important in the general performance of the structure. Pavement designs in these countries are empirical in nature and rely on simple input parameters like California Bearing Ratio (CBR) values. Although widely applicable the traditional CBR test does not provide the mechanical properties such as resilient and permanent deformation characteristics of granular road materials. This paper documents the characterization technique developed to determine the mechanical behavior of granular (sub-) base materials based on CBR test using repeated load cycles. The confining pressure developed in the complex CBR stress state is estimated using strain gauges. Finite Element analysis has been attempted to model the repeated load CBR (RL-CBR) and derive an equivalent resilient modulus. Furthermore, a large scale cyclic load triaxial test was carried out on coarse unbound granular materials (UGMs) to validate the result of the RL-CBR. The RL-CBR test reasonably estimates the resilient modulus of UGMs which can be used as an input in mechanistic pavement design analysis in the absence of triaxial testing facilities.

2025, Journal of Artificial Intelligence and System Modelling (JAISM)

In geotechnical engineering, the CBR test is an essential evaluation tool that can be used in laboratory and field settings. It is essential for figuring out the resistance properties of subgrade soil, whether it is used as the foundation for retaining wall fills, highway embankments, bridge abutments, or earth dams. CBR values provide a valuable metric for assessing the strength of the soil. This paper presents a novel approach to the accurate prediction of CBR values. Using the DT algorithm, the method creates complex and incredibly accurate predictive models. These models include a wide range of intrinsic soil characteristics, including particle distribution, plasticity, linear shrinkage, and the kind and number of stabilizing additives. The dataset of this study consisted of several variables, including LL, PI, PL, MDD, OMC, OPC, SDA, and QD. The DT algorithm improves forecasting accuracy by establishing significant correlations between these soil properties and CBR values. The study incorporates two state-of-the-art meta-heuristic algorithms, the NGO and the EOS, to further improve the predictive model's accuracy. Three unique models are produced by this framework: DTEO, DTNG, and a hybrid DT model. Out of all of them, the DTEO model performs exceptionally well, exhibiting excellent prediction abilities and remarkable generalization. Its performance is rigorously assessed using a range of soil types derived from earlier stabilization tests' outcomes. The DTEO model's remarkable R2 values of 0.996 during the training phase highlight its remarkable accuracy and dependability. Additionally, it achieves an ideal RMSE of 0.732, confirming its accuracy and consistency.

2025

This report discusses the current applications of the dynamic and static cone penetrometers in pavement design and construction. The dynamic cone penetrometer (DCP) is the most versatile rapid, in situ evaluation device currently available. Correlations to CBR, unconfined compressive strength, resilient modulus, and shear strengths, and its use in performance evaluation of pavement layers make it an attractive alternative to more expensive and time consuming procedures. Many useful correlations between the DCP penetration index and other material properties continue to be reported. Other possible applications of DCP such as its use in the quality control of compaction of fill are discussed. In addition, advantages and disadvantages of the penetrometer testing are reported. The static cone penetrometer has also several applications in such areas as the evaluation of resilient modulus of cohesive soils, estimation of CBR, and the determination of relative density of sands. An overview of current practices ae well as areas of possible future trends are reported.

2025

11. Contract (C) or Grant (G) No. (c) 89261 (wo) 4 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered

2025

This paper compares the tests results obtained with two types of presuremeters, one pressuremeter equipped with a monocell probe and the other equipped with a tricell probe (Menard type). These tests were carried out in polymer tubes specifically designed and manufactured for this purpose. These tubes of different stiffness were chosen because they allow to simulate a large range of soil stiffness, they ensure a good repeatability of the results, and finally because they generate information about stiffness and strength. These tests made it possible to quantify the difference in the results obtained with these two pressuremeters in a controlled environment. Potential explanations were proposed and verified in order to explain these differences. Suggestions were made for reducing them.

2025

This paper compares tests results from two types of pressuremeters: one equipped with a monocell probe and the other equipped with a tricell probe (Menard type). These tests were carried out in polymer tubes specifically designed and manufactured for this purpose. These tubes of different stiffness were chosen because they allowed the simulation of a large range of soil stiffness, they ensured a good repeatability of the results, and because they exhibited a three-step deformation pattern similar to the one obtained in soil with pre-bored pressuremeters. These tests show a difference between the moduli measured with these two types pressuremeters. Possible reasons for this difference were therefore analyzed. Finally, a method for reducing this difference was proposed.

2025, Jordan Journal of Civil Engineering

Nowadays, disposal of waste materials has become a matter of serious concern due to environmental and ecological issues. In this paper, an attempt is made to determine an optimum proportion mix suitable for geotechnical applications by blending the locally available clayey soil with sand, fly ash, tile waste and jute fibers. This optimum mix provides a cheaper construction material and helps in effective utilization of waste materials like fly ash and tile waste; thus solving the problem of disposal of waste materials to some extent. In this research, the percentage of waste materials added to the clayey soil to make the optimum mix is obtained on the basis of compaction characteristics and the optimum mix is further checked for strength and permeability characteristics. The basic idea behind this study is to explore the collective benefit of the material properties of waste materials when used in a composite form. It can be revealed from this study that mixing of waste materials brings out significant improvement in geotechnical properties of locally available clayey soil. From economic analysis, it can be concluded that the optimum mix obtained in this study yields an improved and cheaper construction material for the construction of flexible pavement.

2025, Zede Journal

Damage due to soil swelling is very noticeable in wide spectrum of structures such as roads, buildings, canal linings, landfill liners, etc. To evaluate severity of swelling, an accurate assessment of the swell potential is required. The main reason of swelling behavior is water absorption of soil mass in time. And the time required for completion of swelling is relatively long. In view of that several attempts have been made by researchers to obtain time-swell relationships for expansive soils. In this study a simple hyperbolic mathematical model is used to predict the swelling behavior of an expansive soil from Addis Ababa. The main parameters that are needed to run the model are the applied pressure and initial dry density. The other parameters of the model including the initial slope of the swell-time curve, the final slope, the reference swell, and the peak swell were investigated experimentally. Based on the experimental results, empirical relationships were developed for dete...

2025, Zede Journal

The Expansive soil collected from Addis Ababa, Bole sub city, classified as an A-7-5 soil on the AASHTO classification was stabilized using 3% lime, 15% bagasse ash and 15% bagasse ash in combination with 3% lime by dry weight of the soil. The effect of the additives on the soil was investigated with respect to plastcity, compaction and California bearing ratio (CBR) tests. The results obtained indicate an increase in optimum moisture content (OMC) and CBR value; and a decrease in maximum dry density (MDD) and plasticity of the soil for all additives. But there was also a tremendous improvement in the CBR value when the soil is stabilized with a combination of lime and bagasse ash. This shows a potential of using bagasse ash as admixture in lime stabilized expansive soil. Keywords: Expansive soil, bagasse ash, lime, plasticity, compaction and strength characteristics

2025, International Journal of Construction Engineering (IJCE) ,IAEME

In a move toward greener construction methods, researchers have tested a soil stabilization technique using a blend of cement, fly ash, and rice husk-a natural agricultural by-product. The study focused on improving the strength and durability of weak subgrade soils commonly used in infrastructure projects. Soil samples were treated with varying proportions of each material, ranging from 0% to 20%, and subjected to standard tests such as the Proctor compaction test, California Bearing Ratio (CBR), and optimum moisture content analysis. The standout result came from a mix containing 15% cement, 15% fly ash, and 15% rice husk, which delivered the highest strength and load-bearing capacity compared to untreated soil. Beyond

2025, IAEME PUBLICATION

In a move toward greener construction methods, researchers have tested a soil stabilization technique using a blend of cement, fly ash, and rice husk—a natural agricultural by-product. The study focused on improving the strength and durability of weak subgrade soils commonly used in infrastructure projects. Soil samples were treated with varying proportions of each material, ranging from 0% to 20%, and subjected to standard tests such as the Proctor compaction test, California Bearing Ratio (CBR), and optimum moisture content analysis. The standout result came from a mix containing 15% cement, 15% fly ash, and 15% rice husk, which delivered the highest strength and load-bearing capacity compared to untreated soil. Beyond performance, the study highlights a key environmental benefit: the reuse of industrial and agricultural waste. Researchers say this cost-effective combination not only reduces reliance on cement but also promotes sustainable practices in civil engineering—offering a practical path to eco-friendly construction.

2025, Materials

Industrial waste causes environmental, economic, and social problems. In Morocco, the Jorf Lasfar Thermal Power Station produces two types of coal ash with enormous quantities: fly ash (FA) and Bottom ash (BA). FA is recovered in cement while BA is stored in landfills. To reduce the effects of BA disposal in landfills, several experimental studies have tested the possibility of their recovery in the road construction, especially as a subbase. In the first phase of this study, the BA underwent a physicochemical and geotechnical characterization. The results obtained show that the BA should be treated to improve its mechanical properties. The most commonly used materials are lime and cement. In the selected low-cost treatment, which is the subject of the second phase of the study, lime is used to improve the low pozzolanicity of BA while calcarenite sand is used to increase the compactness. Several mixtures containing BA, lime, and calcarenite sand were prepared. Each of these mixtures was compacted in modified Proctor molds and then subjected to a series of tests to study the following characteristics: compressive strength, dry and wet California Bearing Ratio (CBR), dry density and swelling. The composition of each mixture was based on an experimental design approach. The results show that the values of the compressive strength, the dry density, and the CBR index have increased after treatment, potentially leading to a valorization of the treated BA for use in a subbase.

2025, Materials

2025, Journal of Geotechnical Studies

Lateritic soil is a soil layer that is rich in high iron content, derived from the weathering of rocks formed under high temperature and heavy rainfall conditions and having reddish to yellow color. It has been used extensively in road construction, backfilling, and foundation works. This study investigates the effect of stabilizing laterite using quarry dust and limestone powder to improve the geotechnical properties. The soil sample was tested through preliminary laboratory tests, Unconsolidated Undrained Triaxial test, Proctor Compaction, and California Bearing Ratio Tests. The additives (Quarry dust and Limestone powder) were combined in 5%, 10%, 15%, 20%, 1%, 3%, and 5% respectively. The deviator stress at failure was determined and the shear strength parameters were obtained. From the results obtained, the natural soil was classified as A-7-6 of fair to poor plasticity. Results obtained show an increase in the cohesion and angle of internal friction, as the ratio of the combination of the laterite and stabilizers increases. In addition, the maximum dry density, optimum moisture content as well as penetration increased with a corresponding increase in the percentage mixture of quarry dust and lime. The optimum results were however obtained at 10% quarry dust to 3% limestone mixture.

2025, Journal of Geotechnical Studies

Lateritic soils are known to have very poor geotechnical properties such as high plasticity, poor workability, low strength, high permeability, tendency to retain moisture and high natural moisture content. The purpose of this research work was to evaluate the stabilization and engineering behaviour of laterite using Quarry Dust (QD) and cement. Various laboratory geotechnical tests were carried out to determine the index properties in order to classify the soil sample and the preliminary investigations showed that the soil belongs to the A-7-6 class of soil in the AASHTO classification system. Other tests include Specific Gravity, Grain Size Distribution, Moisture Content, Compaction characteristics, Maximum Dry Density (MDD), Optimum Moisture Content (OMC), California Bearing Ratio (CBR), Triaxial and Consolidation of the treated natural soil. The soil was stabilized with concentrations of 0%, 5%, 10%, 15% and 20% of quarry dust and 1%, 3% and 5% of cement. Analysis showed that the highest Specific Gravity occurred at 15% Quarry Dust and 5% Cement. Result also showed that the stabilizers increased the maximum dry density and decreased the optimum moisture content of the soil with the highest MDD occurring at 15% Quarry Dust and 5% cement while the OMC occurred at 5% Quarry Dust and 5% cement. The values of cohesion (triaxial test) and California bearing ratio increased when the percentages of quarry dust and cement were increased with the highest CBR and cohesion occurring at 20% quarry dust and 5% cement respectively. Both stabilizers when combined enhanced the geotechnical property of the soil.

2025, Journal of Geotechnical Studies

Soil stabilisation is vital in foundation and roadway building because it enhances soil engineering qualities. The volumetric change of expanding soil is seen as a challenge in geotechnical engineering practice. The stabilization method has to be safe. In this study quarry dust (QD) in proportions of 5%, 10%, 15%, and 20% and lime in proportions of 1%, 3%, and 5% were used to improve the engineering qualities of laterite. The tests carried out in this study were specific gravity, proctor compaction, consolidation, particle size distribution, Atterberg limits, and triaxial and consolidation tests. The lateritic soil was classified as A-3, A-2-4 and A-2-6 and was found to be acceptable for sub-grade, good fill subbase and base materials. The result showed the highest CBR occurred at 5% quarry dust and 5% lime. Results also showed that the higher the percentage of quarry dust, the strength of the soil. The liquid limit (LL), plastic limit (PL) and plasticity index (PI) of the natural soil samples were 41.1%, 27.96%, and 13.14% respectively. LL of the soil samples falls between intermediate plasticity. The experimental results in general, showed that the admixtures (quarry dust and hydrated lime) improved the engineering properties of the soil.