Maximum Dry Density Decreases Research Articles

Study on the Mechanical Properties of Modified Sludge Soil Based on an SM-C Modifier

The purpose of this study is to solve the problem of the harmless treatment of dredged silt and soil extraction during road construction in lake areas. The silt in the project area is used as the research material to evaluate its engineering applicability as an improved filling material for the roadbed of the lake’s surrounding road. Through indoor pretreatment and a series of mechanical performance tests, including compaction tests, unconfined compressive strength tests (UCS), bearing ratio tests (CBR), triaxial compression tests (CU consolidated undrained), and consolidation tests, we obtained key mechanical parameters of modified sludge soil, such as maximum dry density, optimal moisture content, unconfined compressive strength, bearing ratio, shear strength, and compression characteristics. The research results show that with the increase in modifier dosage, the optimal moisture content of modified sludge soil increases, the maximum dry density decreases, and its compressive strength and shear strength significantly improve. The CBR value also meets the technical requirements of each layer of the roadbed. Specifically, after 7 days of curing, the compaction degree of 10% modified sludge soil can exceed 96%, the unconfined compressive strength reaches 0.819 MPa, the CBR value reaches 17.5, the cohesion measured by triaxial tests is 78 kPa, the internal friction angle is 27°, and it exhibits low compressibility. These findings provide new solutions for environmentally friendly treatment, resource utilization, and road engineering in river and lake sediments.

Calcium Carbide and Wood Ash as Environmentally Friendly Soil Stabilizers for Enhanced Subgrade Performance

This study looks at the potential of waste calcium carbide (WCC) and wood ash (WA) as soil stabilizers to improve the engineering characteristics of subgrade soil. The investigation begins by characterizing the properties of the untreated soil, indicating a liquid limit of 24.6%, linear shrinkage of 7.6%, and a non-plastic nature due to the lack of a plastic limit. In addition, the soil composition comprises a mere 2% of small particles measuring less than 63 μm, while a substantial 74% of the particles fall within the range of 63 μm to 2 mm. The particle density of untreated soil is found to be 2.86, beyond the typical soil limitations. Subsequently, an investigation was conducted to examine the impact of WCC and WA on Atterberg limits, compaction characteristics, and California bearing ratio (CBR) values. The findings indicate that the incorporation of WCC and WA leads to a reduction in the liquid limit by a maximum of 18.70% and linear shrinkage by a maximum of 55.26%. Compaction properties show an increase in optimal water content and a minor decrease in maximum dry density. Importantly, CBR values significantly improved, with the soil treated with 6% WCC and WA demonstrating a CBR value of 26.9%, exceeding the subgrade acceptability requirement in road construction. This study highlights the potential of WCC and WA as cost-effective and sustainable soil stabilizers, particularly in areas where traditional stabilizing materials are limited. More research into optimization and long-term performance can help to realize the full potential of this novel method for soil stabilization. Received: 1 January 2024 | Revised: 26 April 2024 | Accepted: 28 May 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study. Author Contribution Statement Samaila Saleh: Conceptualization, Methodology, Formal analysis, Resources, Data curation, Writing - review & editing, Visualization, Supervision, Project administration. Idris Surajo: Conceptualization, Methodology, Formal analysis, Investigation, Resources, Writing - original draft, Project administration. Muhammad Surajo: Formal analysis, Investigation, Resources, Writing - original draft, Project administration. Abubakar Tsagem Idris: Formal analysis, Investigation, Resources, Writing - original draft, Project administration. Abdullahi Umar: Formal analysis, Investigation, Resources, Writing - original draft, Project administration.

Investigation on the Engineering Properties of Peat Soil Stabilised Using Lime Stabilisation and Alkaline Activation

Peat soil is typically classified as a problematic soil due to its expansive behaviour that possesses geotechnical drawbacks. Thus, the condition of peat soil must be improved prior to any construction works. Stabilisation of peat soil can be done via chemical stabilisation and alkaline activation while incorporating industrial by-products or wastes as addictive. This study aims to investigate the effect of press mud as an additive in lime-stabilized and alkaline activator-stabilized peat soils. Press mud is a by-product of sugarcane juice filtering. The lime adopted is at 3 % and 5.5 % while the alkaline activator is used in cold and warm condition. A total of 5 percentages of press mud have been employed, namely 0%, 0.25%, 0.5%, 1% and 2%. The investigations revealed that regardless of the percentage of lime adopted, the optimum moisture content increases while the maximum dry density decreases when the percentage of press mud incorporated is increased. However, when the lime content is increased, the optimum moisture content increases significantly. The UCS of lime-stabilised peat soil sample achieved the greatest strength improvement when the lime and press mud is used at 5.5% and 0.25%, respectively. In contrast, the unconfined compressive strength (UCS) of 3% lime-stabilised peat soil samples with or without press mud shows comparable 28-day strength. On the other hand, the UCS of peat soil stabilised with alkaline activator shows significant improvement, while addition of press mud further improves the strength. Nonetheless, using warm alkaline activator improves the early strength development but cold alkaline activator results in higher 28-day UCS.

Effect of leachate and used motor oil on the geotechnical and mechanical characteristics of soils with different mineralogy under different moisture conditions

ABSTRACT In order to evaluate the geotechnical characteristics of four types of fine-grained clayey soil, including clay with low plasticity (CL), calcium bentonite (CB), sodium bentonite (SB), and a mixture of 50% CL and 50% SB (CL-SB) from the effect of water, leachate and used motor oil (UMO) was used. Unconfined compressive strength (UCS), indirect tensile strength (ITS), standard compaction, Atterberg limit, and free swelling tests are performed. This results showed that the PI of SB, CB, CL, and CL-SB soils with leachate is 43, 25, 10, and 33% higher than water, respectively. The PI of SB, CB, CL, and CL-SB soils with UMO is 72, 66, 12, and 43% lower than water due to the low dielectric constant. Adding leachate compared to water caused a decrease in maximum dry density (MDD) for CL, CL-SB, SB, and CB by 2.6%, 4%, 6%, and 4.5%, respectively. Also, adding leachate and UMO reduces UCS and ITS of all soils. Due to SB soil’s high cation exchange capacity, the changes in its mechanical and geotechnical characteristics were higher than in other soils. Finally, the increase in soil moisture during the sample construction decreased the soil strength due to the addition of leachate and UMO.

Aggregation and dehydration of excavated soft clay and use for subgrade engineering–Part 1: A laboratory study

The reuse of the excavated soil for subgrade construction, as an alternative to the traditional excavated soil management approach, has demonstrated great potential for engineering application. However, its application is currently hindered by the poor engineering properties of soft soils and the pretreatment process. In this paper, an improved technique employing aggregation and dehydration for rapid stabilization of excavated soft clay was proposed. By wet mixing with stabilizers, excavated soft clay was transformed into separated aggregates with the larger surface areas exposed to air. During turning preservation, aggregates were further stabilized and dehydrated as a result of the combined hydration and enhanced evaporation effect. The performance of the produced stabilized-soil aggregates was explored by performing a series of laboratory tests and it was demonstrated that by enhancing the evaporation effect, moisture content of excavated soft clay decreased by over 20 % in 4 days. Through the aggregation effect, the soft clay tended to be silty in the plasticity chart and experienced an increase in optimal moisture content and a decrease in maximum dry density. Unconfined compressive strength and Californian bearing ratio tests showed that compacted aggregates exhibited reliable strength and water stability because of the enhanced cementitious and pozzolanic reactivity, which was capable for various sections of the subgrade with different classifications. Meanwhile, the performance of compacted aggregates was found to be dominated by the stabilizer content and the characteristics of the raw soil, which indicates that it would be preferred to distinguish the stabilizer dosage and the excavated soft clay to counter different requirements for engineering application. And a draft, dry and thermostatic environment for turning preservation is highly recommended for the purpose of improving the efficiency of excavated soil management.

Effect of Tire Buffings Addition on Compaction Properties of Bentonite-Sand, Bentonite-Rock Dust, and Bentonite-Sand-Rock Dust Mixes

Abstract: In landfills, the compacted bentonite-sand (B:S) combination is widely employed as a liner. Since sand is a scarce and expensive material, other waste materials such as rock dust which possess similar properties are used instead of sand, or in other cases, both sand and rock dust are mixed in varying proportions along with bentonite. Urbanization and population explosion have triggered the continuous increase in industrial waste output, particularly waste tires, which posed several challenges to mankind. Incorporating wastes tire as raw resources have been suggested in various industries. Waste tires as stabilizers and investigation of geotechnical properties of the composite can help to minimize pollution while also providing economic and scientific benefits. Past research indicates short fibre has been shown to improve the ductility, toughness, and resistance to tensile cracking of clays. Fibre-shaped tire buffings or tire dust (T) from the retreading process can be used as a fibre reinforcing element in a liner. The objective of this study is to examine the effect of fibre-shaped tire dust (T) addition on the compaction characteristics of bentonite-sand (B:S),bentonite-rock dust (B:R), and bentonite-sand-rock dust(B:S:R) mixes. Locally available sand and rock dust, and commercially available bentonite have been used in this research. The gradation of the (T) used is equivalent to poorly graded sand. Here, all the mixes were prepared with different (T) contents (2 to 16%), and the standard compaction tests were performed. The results reveal that when the tire dust increases, the variation in the optimum moisture content and maximum dry density follow a consistent and predictable pattern. To put it another way, with the increase in the percentage of tire dust in the combination, the optimum moisture content increases while the maximum dry density decreases. Additionally, relationships were offered to predict the maximum dry density and the optimum moisture content with various tire dust content of the composite to be functional in the field

Experimental Study on Engineering Characteristics of Cement-Lime-Improving Silt in Eastern Henan Province

With the construction of expressways in eastern Henan, silt has been widely used as a filling material. However, the silt in this area is lacking clay, the content of active oxides in the soil is low, and the soil particles are bonded together. The property is poor, the erosion resistance is not strong, and the direct filling of the roadbed is prone to engineering problems. Due to the obvious regionality of silt in eastern Henan, this paper firstly analyzes the basic physical properties of silt in eastern Henan using compaction, compression, direct shear and particle gradation tests. The research displays that with the increase of the dosage of cement or lime, the optimal water content increases, while the maximum dry density decreases. The compressibility decreases linearly with the increase of the content. The improved soil has a significant increase in large particles. When the dosage of lime is 2%–6%, the improved soil has a good gradation, and the improved soil has a significant increase in large particles. When the dosage is 2%–6%, the improved soil has a good gradation, and the improvement effect on the cohesion is much greater than that on the internal friction angle. The comprehensive analysis of cement lime shows that the dosage of cement should be 4%–6%. In the early stage, the improvement effect of cement on silt is better than that of lime.

Lime stabilization to improve clay-textured forest soil road subgrades

ABSTRACT Lime is the oldest known traditional soil stabilizer, especially for clay soils. In the Hyrcanian forest in northern Iran, clay-textured soils are widespread and cause many problems for infrastructure development, particularly forest roads. Therefore, the current study investigated the stabilization effect of different percentages (5%, 7%, and 9% by weight) of lime on a typical clay with high plasticity. Laboratory tests were Atterberg limits, standard Proctor, and unconfined compressive strength (UCS) and were used to determine the extent of stabilization. Lime decreased the liquid limit and plasticity index, but increased the plastic limit. The greatest decrease in liquid limit and plasticity index was 48% and 94%, respectively, for the 9% lime treatment and the greatest increase in plastic limit was approximately 39% when 7% lime was added. Furthermore, the greatest decrease in maximum dry density was 5% with the 9% lime addition and the greatest increase in optimum moisture content was 9% when lime was added at both 5% and 7%. Lime treatments generally had a positive effect on soil compressive strength, except when added at the 7% rate. At 7% lime, compressive strength decreased as compared with the control soil. The best improvement in soil strength was achieved with 9% lime treatment; with a 39.45 kN/m2 (6%) increase in the strength. Based on these laboratory findings, lime can improve the engineering properties of expanding clay soils in a forest road. However, further field studies are necessary to determine if the effects of our laboratory study are similar to road subgrades.

UTILIZATION OF INDUSTRIAL WASTES FOR IMPROVING GEOTECHNICAL PROPERTIES OF COLLAPSIBLE SOIL

At the present time the disposal of industrial wastes has become a challenge for most countries. This research aims to study the effect of mixing the industrial textile sludge on geotechnical properties of collapsible soil. The experimental program studies the effect of textile wastes on Atterberg limits, collapse potential, compaction, CBR, and shear strength parameters. The percentages of textile wastes mixed with soil are 4, 8, 12, 16, 20, and 24 %. The results indicated that the collapse potential of untreated soil is significantly decreased from about 11% to 2.6% at 24% of textile sludge. Shear test results show an increase in cohesion and decrease in the internal friction angle. For Atterberg limits there was an increase in liquid limit. For Compaction results, it is noticed a decrease in maximum dry density and an increase in optimum moisture content. CBR values for all samples indicates the suitability of using soil and soil-sludge mixtures only in subgrade layer of pavement. It was found that the reuse of textile sludge with collapsible soils considers an economic method to improve the physical and mechanical properties of the soil, in addition, it could be considered as sustainable management of textile sludge which leads to a reduction in the consumption of natural resources and preserves the surrounding environment through decreasing the retention of these wastes to a minimum

Nano parçacık silisyum dioksit (SiO2) ile yüksek fırın cürufu karışımının kompaksiyon özelliklerine etkisi

This study investigates the effect of using the mixture of silicon dioxide (SiO2) nanoparticles with blast furnace slag in fine grained soil stabilization. The main motive of this study is to evaluate the compaction characteristic (maximum dry density and optimum water content) of stabilized fine-grained soil using SiO2 nanoparticles and blast furnace slag. The standard proctor tests were conducted to obtain compaction characteristics for stabilized fine-grained soils. Two different types of samples were prepared in which soil was mixed with different blast furnace slag percentages (10%, 20%, 30%, and 40%) and small amounts (%1 and 1.5%) of SiO2 nanoparticles. The effect of the blast furnace slag and the mixture of SiO2 nanoparticles with blast furnace slag were investigated, separately. The test outcomes revealed that a decrease in maximum dry density with the increase in blast furnace slag content. Moreover, the addition of SiO2 nanoparticles with blast furnace slag to the soil increased the maximum dry density. The obtained results show that the small amount of SiO2 nanoparticles generally improves compaction characteristics.

Study on Pavement Soil Subgrade Properties with Reinforced Fibres

The present examination researches the advantages of strengthening the subgrade soils in flexible pavements where two different types of fibres (jute and polypropylene fibre) were used and were randomly mixed with soil. Proctor test, unconfined compression test, California bearing ratio (CBR) test and triaxial test were conducted to evaluate the compressive and shear strength of subgrade soil. Both the fibres were added at various percentages (0.5–1.5%) by dry weight of soil for improving soil strength. The prime point of this examination is to assess the usefulness of fibres as soil reinforcement and to evaluate the effect of various percentages of fibre contents on the compressive strength and stiffness of subgrade soil. It is found from the results that maximum dry density decreases and optimum moisture content increases with an increase in fibre content. It is seen that the CBR value increases with an increase in fibre content up to a specific increment of fibre, yet diminishes with additional inclusion of fibre in soil. The maximum CBR value and compressive strength are found at 0.75% jute fibre and 1.0% polypropylene fibre content. The CBR value of the soaked unreinforced soil is 4.17%, which has increased to 8.97% and 10.61% for 0.75% jute fibre and 1.0% polypropylene fibre, respectively. Including of fibre improves the CBR value of soil which reduces the thickness of the pavement structure and in turn reduces construction cost of pavement structure.

Some studies on microstructural behaviour and unconfined compressive strength of soft soil treated with SiO2 nanoparticles

The nanoparticles are basically the smallest particles known in the soil environment. Soil being a particulate material and its essential particles have a different size range. On the other hand, nanoparticles range between 1 and 100 nm and most properties of nanoparticles are size-dependent. In this paper, an experimental study was conducted to study the improvement of strength characteristics of soil treated with SiO2 nanomaterial. Also, X-ray diffraction tests were performed on collected soil samples and nanomaterial. Furthermore, scanning electron microscope analysis was performed to identify the underlying mechanisms of nanomaterials. Soft soils of two types were collected and were treated with nano-silica (SiO2) additive at percentages of 0.5%, 1.0%, 1.5%, and 2.0%. The test outcomes revealed that the unconfined compressive strength increased significantly with increasing percentage of nano-silica. Moreover, a decrease in maximum dry density and increase in optimum moisture content of treated soil were observed. The addition of nanoparticles increased the sample’s reactivity even at an early age and subsequently strength was increased. Therefore, the main aim of this paper was to stabilize soft soil deposits for utilization of various geotechnical applications for sustainable environment.

Experimental study on potential of oyster shell ash in structural strength improvement of lateritic soil for road construction

This study investigated the effect of oyster shell ash (OSA) on the geotechnical properties of lateritic soil. Laboratory studies were performed using lateritic soil treated with up to 15 % OSA. The result shows a decrease in maximum dry density (MDD) with corresponding increase in optimum moisture content (OMC). Unconfined compressive strength (UCS) values generally increased with increased OSA content and curing age, while resistance to loss in strength increased to peak of 18 % at the threshold of 6 % OSA content. Peak California bearing ratio (CBR) values (soaked and unsoaked) were obtained at a threshold of 6 % PSA content. The Fourier transformation infrared (FTIR) spectroscopy of the soil, OSA and soil + OSA blend show the distinctiveness of the relevant functional groups in relation to their specific band. The treated soil show H-O-H bending of water linked to 2Al3+, Si-O, Si-O-Si. The scan electron microscopy (SEM) and electron diffraction spectroscopy of treated soil revealed the formation of compounds responsible in strength improvement of the soil. Generally, OSA show significant strength improvement on the lateritic soil. This study has shown that OSA can be beneficially used in lateritic soil improvement and is also recommended as admixture in either lime or cement stabilization of deficient lateritic soil for use in road construction.

Effect of silica fume on engineering properties of expansive soil

Rapid growth of urbanization and industrialization has led to drastic industrial waste which has become a giant threat to our nature. Minimizing industrial waste now days posing a serious problem in the present scenario. To tackle the problem now a days many innovative and non-traditional researches on waste utilization is gaining importance. The primary purpose of this experimentation is to evaluate the suitability of using the low-cost material i.e. Silica fume as a soil stabilization material. This project work presents the study of expansive soil stabilized with silica fumes which was assembled from an idyllic area named Kalatunga located in Kendrapada district of Odisha state. Soil stabilization was done with various percentages of silica fumes (10 to 100%). The differential free swell (DFS), Atterberg’s limits, standard proctor compaction, california bearing ratio (CBR), unconfined compressive strength (UCS) test and unconsolidated un-drained triaxial (UU) test were carried out on natural and silica fume stabilized soils. Results display that addition of SF scales down the DFS. The compaction curves point out that addition of silica fume results in an increase in optimum moisture content (OMC) and decrease in maximum dry density (MDD). The addition of stabilizers (i.e. silica fumes) escalates the cohesion (C) values in UCS along with an in increase in cohesion and angle of shearing resistance (Ø) in UU triaxial test demonstrating progress in the strength properties of soil.

Moisture-Density Relationship of Bottom Ash, Lime Stabilized Bangkok Clay as a Potential Pavement Material in Thailand

Expansive clayey soils like Bangkok clay can shrink and swell with water contact. Therefore, the presence of such soils tends to damage the road conditions with a higher frequency of rainfall in Thailand. The presence of expansive clayey soil has brought the concept of stabilization of such roads with any other stronger materials. This paper shows the test results on the moisture-density relationship of bottom ash and lime stabilized Clayey soil to use as a pavement material in Thailand. In this study, a waste material produced from coal combustion called bottom ash was used as a replacement material and quicklime as a binding material. During the tests 10%, 20%, 30% and 50% bottom ash and 4%, 8%,12% Lime were used. The result shows a decrease in Maximum Dry Density and increase in Optimum Moisture Content with an increase in each amount of replacement material.

Impact of rice husk ash (RHA) and nylon fiber on the bearing capacity of organic soil

In the south-west part of Bangladesh, the regular systems of foundation are not suitable for the massive structure because an organic soil layer exists at a distance of 3–6 m from the ground surface. The existence of organic soil layer causes excessive settlement due to its high compressibility and low shear strength. To solve this matter, soil improvement is needed indispensably because it drops the construction expense and decreases the risk of further damage to the structures. Soil stabilization is an important method in the field of construction. The techniques of stabilization are used to enhance the strength of expansive or poor organic soil. In Bangladesh, huge amounts of industrial wastes are being produced every year due to fast urbanization and industrialization. Disposal of these waste materials is important as these are creating harmful effects on the environment. Rice husk ash (RHA) and nylon fibers are enormously available as industrial waste are dangerous if not disposed technically. Utilization of these industrial waste in ground improvement is likely to offer an admissible solution. This research represents the investigational results acquired from tests performed on organic soil stabilized with RHA and strengthened with randomly distributed nylon fibers. To investigate the impact of RHA and nylon fiber on strength properties of organic soil, standard proctor compaction, unconfined compressive strength (UCS), unsoaked and soaked CBR tests were conducted first on the soil samples partially replaced by RHA with dose 0%, 5%, 10%, 15%, 20% and then soil plus optimum percent of RHA and different content of nylon fiber (0.3%, 0.5%, 0.7%, 1%, 1.2%). The experimented results disclose that inclusion of different dosages of RHA and nylon fiber in organic soil leads to increase in the optimum moisture content and decrease in maximum dry density. The experimental results also express that the suggested technique is very effectual to improve the strength properties of poor organic soil in words of UCS, unsoaked and soaked CBR values. The result of this research work can be used as a guideline for soil improvement and can be used in the field of civil engineering.

Stabilized soil incorporating combinations of rice husk ash, pond ash and cement

The paper presents the laboratory study of clayey soil stabilized with Pond ash (PA), Rice husk ash (RHA), cement and their combination used as stabilizers to develop and evaluate the performance of clayey soil. The effect of stabilizer types and dosage on fresh and mechanical properties is evaluated through compaction tests, unconfined compressive strength tests (UCS) and Split tensile strength tests (STS) performed on raw and stabilized soil. In addition SEM (scanning electron microscopy) and XRD (X-ray diffraction) tests were carried out on certain samples in order to study the surface morphological characteristics and hydraulic compounds, which were formed. Specimens were cured for 7, 14 and 28 days after which they were tested for unconfined compression tests and split tensile strength tests. The moisture and density curves indicate that addition of RHA and pond ash results in an increase in optimum moisture content (OMC) and decrease in maximum dry density (MDD). The replacement of clay with 40% PA, 10% RHA and 4% cement increased the strength (UCS and STS) of overall mix in comparison to the mixes where PA and RHA were used individually with cement. The improvement of 336% and 303% in UCS and STS respectively has been achieved with reference to clay only. Developed stabilized soil mixtures have shown satisfactory strength and can be used for low-cost construction to build road infrastructures.

Behavior of cement-stabilized fiber-reinforced pond ash, rice husk ash–soil mixtures

In order to study the effect of addition of rice husk ash, pond ash, cement and fiber on the compaction and strength behavior of clay, a series of tests were performed. Modified proctor tests were conducted to evaluate the compaction behavior, while unconfined compression tests (UCS) and split tensile strength (STS) tests were conducted to evaluate the strength properties of clay. For testing purpose specimens were prepared with different amount of admixtures. Pond ash (PA) and rice husk ash were added to clayey soil at ranges of 30–45% and 5–20%, respectively. Polypropylene fibers of length 6 mm and 12 mm are used in this study with different contents as 0, 0.5, 1.0 and 1.5% by dry weight of mix whereas cement contents used are 0, 2 and 4%. To study the effect of curing on strength property, the specimens were cured for 7, 14, and 28 days and tested. Test results have shown that the maximum dry density decreases and optimum moisture content increases with the addition of admixtures, but fiber inclusion have marginal effect. The results shows that the inclusion of fiber reinforcement within un-cemented and cemented soil caused an increase in the UCS, STS and axial strain at failure, decreased the stiffness and the loss of post-peak strength, and changed the cemented soil brittle behavior to a more ductile one. Strength of clay improves by the addition of admixtures and fibers. The study has shown that combination of clay, RHA, PA, cement and fiber can be used as light weight fill material in different structures like embankment, retaining wall etc.

The Tests on the Lime-Treated Expansive Soils Compaction Characteristics

The compaction characteristics of the lime-treated expansive soils from the planning airport in China's Ankang were studied through the heavy compaction tests. The results show that all these elements such as lime content, water content, soil height, wetting time have a certain effect on dry density. As the lime quality ratio increases, the optimum water content under heavy compacting standard of improved soils increases but the maximum dry density decreases. With the increase of lime content, the effect of water content on dry density decreases while the water content near to its optimum value. Soils with the lower height have higher dry density when compaction energy, lime content and water content unchanged. As the wetting time increases, the maximum dry density shows a decreasing tendency until after 48 h it remained stable. It indicates that with the same lime content the order of primary factors influence on dry density are water content, wetting time, soil height. Finally, the lime stabilizing principle to expansive soil is explained through by applying scanning electron microscope technique.

Compaction Characteristic of Lime Modified Expansive Soil

Through compaction test discussed about the compaction characteristics of expansive soil by lime modified in middle of Shandong province. The results show that the optimum moisture content is lower when the expansive soil is cured by dry compaction method, and the maximum dry density is higher. Compaction curve appeared the phenomenon of two peaks when expansive soil is cured by wet compaction method.Lime content of lime improved expansive soil, particle size composition, age and compaction function have influence on compaction curve.With the increase of the quantity of lime, the optimum moisture content increases, the maximum dry density decreases. With the age growth, the optimum moisture content increase slightly,the maximum dry density decreases slightly. The bigger the compaction work, the smaller moisture content is, the larger the maximum dry density is.