Compaction Energy Level Research Articles

Influence of Energy on Compaction Characteristics of High Expansive Soils

Each soil type has different behavior with regard to determination of maximum dry density and optimum moisture content and therefore any soil type has its own compaction requirements for experimental purposes and for control the compaction in the field. The general purpose of this study is to a better understanding of the compaction characteristics of high expansive soils, with emphasis on the relationships of moisture content and dry density of high expansive soils at a range of compaction energy levels. To achieve this purpose, high expansive soils samples were subjected to Atterberg limit and a set of laboratory compaction tests to find compaction characteristics namely; maximum dry unit weight and optimum water content of high expansive soils at different compaction energy (compaction effort) for different number of hammer blows per each layer range from 10 to 50, which varied the energy per unit volume from 356 KN/m3 to 1188 KN/m3.Rather than single peak compaction curves, the most achieved compaction curves are an irregular one and half peak compaction curves. According to the comparison results of different compaction energy, it was concluded that the maximum dry unit weight of high expansive soil was not highly affected by gradually increase of applied energy. The results showed that, the maximum dry density of tested expansive soils sample increased from 1.48g/cm3 to 1.6g/cm3 with increase of compaction energy from 356 KN/m3 to 1188 KN/m3.

Effect of compaction characteristics on hydraulic conductivity performance for sedimentary residual soil mixed bentonite as compacted liners

This paper discusses on the compaction effect to the hydraulic conductivity performance for the sedimentary residual soil mixed bentonite. This mixture is proposed as a barrier material in landfill area and may possibly potential materials for use as compacted soil liners in landfills for leachate protection. A laboratories series was conducted to evaluate the effectiveness of compaction characteristics on sedimentary residual soil mixed with different percentage of bentonite (5%, 10% and 15%). The sedimentary residual soil sample was used in this study and was collected in sedimentary residual formation area in Salak Tinggi, Malaysia and named as Salak Tinggi soil. The mixed samples were compacted at three different compaction effort with different energy to determine the maximum dry density (MDD) and optimum moisture content (OMC). Then, the permeability test to determine the hydraulic conductivity (k) was conducted at MDD condition at every compaction effort at effective stress of 100 kPa. The results show that the MDD value were slightly low for the entire soil sample mixed with bentonite at all compaction energy level. Instead it shows all the three different compaction efforts applied to the mixed soil samples with bentonite yielded hydraulic conductivity less (k ≤ 1x10−9m/s). In fact, the increment of bentonite content also resulted in lower of MDD value and hydraulic conductivity value. However, MDD values were found to be higher for mixed soil when compacted with high compaction effort. The results of hydraulic conductivity tests demonstrated that hydraulic conductivity, k ≤ 1x10−9m/s can be achieved just by using lower compaction energy for the soil mix with bentonite. Instead it considered as suitable materials for liner due to the hydraulic requirement for soil barrier, k ≤ 1x10−9m/s. This finding show that compaction efforts play an important role for workability of the mixtures and significantly to be used as compacted of soil liner materials.

Improvement of the Index and Compaction Characteristics of Black Cotton Soil with Palm Kernel Shell Ash

The expansive soil obtained from Baure in Yamaltu Deba Local Government Area was rich in clay mineral (montmorillonite), unstable and difficult to use for construction purposes. The soil treated with up to 12% palm kernel shell ash (PKSA an agro – waste) by weight of dry soil to improve index properties and compaction characteristics of the soil using PKSA. Index tests were carried out to classify the natural soil, while the moisture-density relationships were determined by compaction tests on the natural and treated soils using three energy levels viz, British Standard light (BSL), West African Standard (WAS) and British Standard heavy (BSH). BCS used in the study was classified as A-7-5 (20) using the American Association of State Highway and Transportation Officials (AASHTO) and CH group in the Unified Soil Classification System (USCS). Tests results show that specific gravity of the soil increased from 2.29 for the natural to 2.34 at 12% treatment. Liquid limit decreased from 76.2% for natural to 73.4% at 10% PKSA content. Plastic limit increased from 40% for the natural soil to 47.1% at 12% PKSA content treatment. Maximum dry density (MDD) values decreased from 1.44Mg/m3, 1.5Mg/m3 and 1.65Mg/m3 for the natural soil to 1.38Mg/m3 at 10%, 1.45Mg/m3 at 10% and 1.56Mg/m3 at 6% PKSA content for BSL, WAS and BSH compaction energy levels respectively. On the other hand, optimum moisture content (OMC) value decreased from 28.5% and 22.4% for the natural soil to 22.4% and 21.0% at 12% PKSA content for BSL and WAS energies respectively while the value for BSH energy increased from 18.2% to 19.0% at 8% PKSA content. Results show that PKSA is suitable for the improvement of the index properties and compaction characteristics of BCS; and its beneficial use will reduce the attendant disposal problem on the environment.

Cold asphalt mix with emulsion and 100% rap: Compaction energy and influence of emulsion and cement content

The present work aims at determining the conditions for the compaction of cold recycled mixtures with emulsion and 100% RAP. Additionally, the influence of the emulsion and cement on the final properties of the recycled mixtures has been investigated. To achieve these purposes, reclaimed asphalt material coming from the milling of a distressed pavement was mixed with different proportions of water, asphalt emulsion and cement. The mixtures were compacted by a gyratory compactor. As a result of the investigation, it is recommended to apply a compaction energy level of 100 gyrations for specimens 100 mm diameter and 60 mm height, and an energy of 200 gyrations for specimens 100 mm diameter and 100 mm height. As for the mechanical properties of the mixtures, the laboratory tests showed that the presence of cement contributes to improving the sensitivity to water attack, the resistance to permanent deformations, the stiffness modulus and the fatigue life of the mixtures.

A novel approach to evaluating the compaction control of soils

Soil compaction is an important operation during the construction of road embankments, railway subgrade, earth dams and compacted clay liners for waste disposal. Soil compaction is usually controlled based on the ratio of the dry density of the soil to the soil water content. However, this relationship presents problems in both the laboratory and in the field when using excess compaction energy levels in cohesive soils with a high natural water content, including differences in the compaction energy levels and a reduction in strength as a result of over-compaction. The compaction curve, which considered the compaction energy levels, is usually unknown in the field and the main factors influencing the stiffness and strength of compacted soils are the dry density and the degree of saturation. We show here compaction results for soils in terms of the dry density and degree of saturation and introduce the concept of an optimum compaction line.

Effect of Density on Consolidation and Creep Parameters of Clay

Effect of density on consolidation and creep parameters of a clay soil was investigated using a soil classified according to Unified Soil Classification System (USCS) as Clay of High plasticity (CH) and composing majorly of secondary minerals, including montmorillonite. The air-dried soil was compacted at five different compaction energy levels (Reduced Standard Proctor compaction energy, Standard Proctor compaction energy, West African compaction energy, Reduced Modified Proctor compaction energy, and Modified Proctor compaction energy). Specimens for consolidation tests were molded at the five different compaction energy levels (densities). The consolidation parameters (initial void ratio, compression index, and preconsolidation pressure) were observed to be empirically related to the compaction energy. The creep parameters (i.e. primary compression index, secondary compression index, and magnitude of creep) were observed to increase with increases in loading to 387kN/m2, after which the values decreased. Curves resulting from these relationships were observed to increase with increases in compaction energy level and tent towards straight line at Modified Proctor compaction energy. Maximum magnitude of creep estimated for three years was observed to reduce from 455.5 mm at Reduced Standard Proctor compaction energy through 268 mm at West African compaction energy to 247.4 mm at Modified Proctor compaction energy levels.

Compaction performance analysis of alum sludge waste modified soil

Sustainable construction is one of the ultimate requirements of the engineering field. Addition of waste materials not only contribute to the improvement of the density of soils but also help in the enhancement of its strength properties. In the field, compaction is achieved by compactors and rollers, which consumes a lot of energy for this purpose. In this study, two methods related to compaction energy have been applied to study the relation of compaction energy with the strength of soil before and after addition of alum sludge as a soil stabilizer. An advanced Artificial Neural Networks (ANNs) technique has been applied with reference to the addition of alum sludge percentage, plasticity index, specific gravity, optimum moisture content, maximum dry density, AASHTO classification, USCS classification, and group index. It was found that soil strength can be improved even at a low compaction energy level of 600KN-m/m3 by the addition of optimum percentage of 8% alum sludge as a soil stabilizer. So, roller compaction effort can also be reduced by addition of this soil stabilizer to save compaction cost i.e. saving of roller fuel consumption and rental cost as well. This study will not only help in environment-friendly construction but will also manage finance by utilization of optimum compaction energy in the mega projects.

Estimation of the compaction characteristics of soils using the static compaction method

Ground improvement using mechanical stabilization is commonly applied by performing the standard Proctor compaction test, which requires a significant quantity of soil, usually obtained from open pits. A static compaction test is an alternative laboratory compaction test. Although researchers have shown that the results of miniature size static compaction tests are comparable with that of standard Proctor tests in terms of the maximum dry density and the optimum water content, no attempt has been made to compare the two fundamental properties of the compacted soil: undrained shear strength and hydraulic conductivity. The scope of this investigation was to estimate the level of static compaction energy required to (1) obtain a compaction curve similar to that of the standard Proctor test; (2) reconstruct compacted soils using the standard Proctor and static compaction tests at the optimum water content; and (3) compare the undrained shear strength and hydraulic conductivity of compacted soils. The compacted soils at the predetermined energy level were subjected to hydraulic conductivity tests using the rigid-wall falling-head permeability method. Undrained shear strength tests were performed by employing a high-capacity laboratory vane shear apparatus on compacted samples of both the standard Proctor and static compaction tests. The present investigation revealed that the static compaction test, requiring about only 10% of the soil necessary to perform the standard Proctor method, provides comparable results in regard to hydraulic conductivity and undrained shear strength.

Microbiological induced carbonate (CaCO3) precipitation using clay phyllites to replace chemical stabilizers (cement or lime)

The objective of the present study is to develop a biotechnological tool for a new application of clay phyllites as stabilized materials in linear works replacing chemical stabilizer (e.g. cement or lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Bacillaceae family (Bacillus pasteurii). Part of the development process conducting a chemical and mineralogical characterization and an examination of physical and hydromechanical properties. The results of this study show that the effect of bacteria on clay phyllites increases the calcium carbonate content, specific surface area and plasticity values. These increased values are caused by the addition of a non-plastic component to clay phyllites resulting in a more aggregated structure through the precipitation of calcium carbonate from the bacteria, ultimately filling the pores of this material. Microbiological treatments on clay phyllites tends to aggregate the original particles, creating aggregates that are partially associated with the formation of calcium carbonate. Said process is influenced by the curing and compaction procedures conducted on samples, which also cause breakage of carbonated structures formed during treatment. As a result of this breaking process of aggregates, some compaction energy is lost and the treated samples do not reach the maximum dry density of the natural state for the same level of compaction energy applied. Treated samples display a slightly larger friction angle with no cohesion, consistent with filling properties and denser condition. Compressibility is consistently lower than that of the natural state. Comparison of collapse data shows that the occurrence and amount of collapse are controlled by the as-compacted dry density. It is also determined that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the sample for the filling of pores (size ranges 3–50 μm) with calcium carbonate. However, the post-ageing compaction destroys the initial binding/cementation effect.

Compacted states and physical properties of soil controlled by the degree of saturation during compaction

For satisfactory performance of soil structures, it is necessary to properly control soil compaction ensuring the physical properties of compacted soil required in design. Usually the dry density ρd and the water content w are controlled in relation to the maximum dry density (ρd)maxand the optimum water content wopt determined by laboratory compaction tests on a chosen representative sample at a certain compaction energy level CEL. Although CEL and soil type affect significantly (ρd)max, wopt and physical properties, they change inevitably, sometimes largely, in a given project while field CEL may not match the value used in the laboratory compaction tests. In comparison, the optimum degree of saturation (Sr)opt(i.e., Srwhen (ρd)maxis obtained) and the normalized compaction curve (i.e., ρd/(ρd)maxvs. Sr- (Sr)optrelation) for given CEL and soil type are insensitive to variations in CEL and soil type and they are essentially fixed in a given project. Besides, the stress-strain and hydraulic properties of compacted soil are controlled by ρd and “Srat the end of compaction relative to (Sr)opt”. It is proposed to control w and CEL so that Sr= (Sr)optwhile ρd becomes large enough to ensure the physical properties required in design fully taking advantage of available field CEL on site. A case history of earth-fill dam construction in Japan following this soil compaction control method is reported.

Improving bituminous mixture performance by optimizing the design compaction energy – A cost effective approach for better pavements

The design of bituminous mixtures has been improved with new analytical methods and enhanced laboratory tests. However, the adoption of these methods increases the complexity and cost of the design process and may not provide better bituminous mixtures nor improved pavement performance. The aim of this study was to analyse how a more flexible design method, which takes into account in-service conditions, can be a useful tool to improve the overall performance of the mixtures. Two mixtures, an AC20 and a SMA12.5, were designed using current design methods and a procedure based on volumetric design. The performance of the studied blends was characterized using laboratory tests. An analysis of the obtained results was made for the Portuguese in-service conditions, based on current pavement design guidelines. From this analysis values were proposed for the compaction energy levels necessary to design both mixtures, ranging from 45 to 85 gyrations for the AC20 and from 55 to 75 gyrations for the SMA12.5. A cost-benefit analysis was made to assess how mixtures designed with the proposed methodology performed when compared to those designed by the current design methods. For some applications, weighted performance variations were up to 40% while cost increase was below 5%. The results show this approach can be very cost-effective in increasing the performance of the bituminous mixtures and achieve better and more durable pavements.

Prediction of Compaction Characteristics of Soils from Index Test’s Results

This paper presents some attempts at prediction of compaction characteristics of soils using the results of the index tests. A data bank, including 728 compaction tests, was compiled. Each case includes the results of soil type, grain size distribution, Atterberg limits (WL and WP) and specific gravity of soil particles, as well as the compaction characteristics, maximum dry density and optimum moisture content were calculated under different levels of compaction energy. Using artificial neural networks (ANNs) and multi-linear regression (MLR), the applicability of basic information about soils to estimate the compaction characteristics was evaluated. A sensitivity analysis accomplished on the results of ANN method, demonstrated that fine content has the most pronounced effect on the accuracy of compaction characteristics prediction. Using a trial and error approach and combining the different individual variables, the efficiency of multi-linear regression models were improved. However, the comparisons showed that ANN models are more effective in capturing the correlation among compaction characteristics of soils and their index properties, while the ANN shortcomings, due to their black box nature, make MLR models more useful in prompt estimations.

EFFECT OF SODIUM CHLORIDE ON THE WETTING INDUCED COLLAPSE STRAIN OF SOILS

Collapsible soils are unsaturated soils which present the potential for large strains and complete change to the whole particle structure after wetting with or without loading. These soils are characterized with loose structures composed of silt to fine-sand-size particles. Collapsible soils are deposited in arid and semi-arid regions. Due to the expansion of human activities, these regions are occupied aggressively leading to the use of large quantities of water which create favorable conditions for soil collapse. The soils failure leads to severe damages and large distresses to man-made structures. The experimental study on reconstituted soil in laboratory consists of the evaluation of the effect of a saline solution of sodium chloride at different, water content and levels of compaction energy on the collapsible potential. The method used is based on oedometer tests with variation of the vertical stress. The study clearly reveals the influence of the salt concentration on the change of microstructural characteristics of the reconstituted soil and reduction of the collapse potential .

Importance of controlling the degree of saturation in soil compaction linked to soil structure design

Abstract In the typical conventional fill compaction, the dry density, ρd, and the water content, w, are controlled in relation to reference values, (ρd)max and wopt, determined by standard laboratory compaction tests using a representative sample at a certain compaction energy level, CEL. Although CEL and soil type affect significantly (ρd)max and wopt, they change inevitably, sometimes largely, in a given earthwork project while field CEL may not match the value used in the laboratory compaction tests. Compaction control based on only an index of strength/ stiffness of compacted soil has such a drawback that, for a fixed value of ρd, the index may increase significantly as the degree of saturation, Sr, of compacted soil becomes lower than the optimum degree of saturation (Sr)opt defined as Sr when (ρd)max is obtained for a given CEL. In comparison, the value of (Sr)opt and the unified compaction curve in terms of ρd/(ρd)max vs. Sr − (Sr)opt relation of compacted soil are rather insensitive to variations in CEL and soil type. Besides, CBR (unsoaked and soaked), the unconfined compression strength, the elastic shear modulus and the collapse upon submerging of compacted soil and the cyclic undrained shear strength and the coefficient of hydraulic conductivity of saturated soil are all controlled by ρd and “Sr at the end of compaction”. As a standard method, it is proposed to control the values of w and ρd in such that Sr becomes (Sr)opt while ρd becomes large enough to ensue soil properties required in design fully taking advantage of available CEL. It is argued that the compaction control keeping Sr larger than a certain value (or the air void ratio va lower than a certain value) without controlling ρd is relevant as a simplified method only if Sr is controlled to become (Sr)opt while always keeping CEL high enough to ensure the soil properties required in design.

Simplified Method to Predict Compaction Curves and Characteristics of Soils

Improvements of the soils in sites are usually necessary to achieve the desired strength, compressibility and hydraulic conductivity of soils. Generally, improvement in compaction is preferred and applied in sites. The compaction curve and associated characteristics, namely maximum dry unit weight and optimum moisture content, should be determined in the laboratory by using Proctor test procedures. However, a number of Proctor tests need to be carried out for projects like earth dams, embankments and highways. In this paper, a simplified and dependable way of obtaining compaction characteristics and compaction curves at different compaction energy levels for preliminary designs is introduced. For this purpose, Proctor compaction tests were conducted with different soils and at different compaction energy levels apart from using extensive results found in the literature. It was found out that by only getting the compaction characteristics from plastic limit an approximate compaction curve can be obtained from family curves. The approximate compaction curve compares well with the tested values too. Maximum dry density predicted is 0.986 times the maximum dry density at plastic limit, whereas predicted optimum moisture content is 0.99 times the actual optimum moisture content.

Briefing: Lateritic soil and calcined kaolin for earth embankments

Compacted lateritic soil treated with calcined kaolin was considered as a potential material for construction works in this study. The tests carried out were consistency limit, compaction, unconfined compressive strength and shear strength tests. The calcined kaolin contents were 2·5, 5·0, 7·5, 10·0 and 12·5%, all measured by weight of the dry soil. The specimens of the soil mixtures were prepared using two compaction energy levels – namely, the British standard light (BSL) and West African standard (WAS) – at moulding water contents of −2, 0, +2, +4% of the optimum moisture content. The results showed that consistency limits and optimum moisture content reduced, while the maximum dry density rose with increase in calcined kaolin content. The compressive strength improved up to 97 and 115% for BSL and WAS, respectively, while shear strength increased by 137·80% with calcined kaolin content up to 12·5%. The compacted lateritic soil without treatment could not satisfy the compressive strength requirement for some earth embankments such as liners, but up to 5% treatment of calcined kaolin at the optimum moisture content was found suitable for BSL and WAS.

Effect of Compaction Energy on Engineering Properties of Expansive Soil

Swelling of expansive clays is one of the great hazards, a foundation engineer encounters. Each year expansive soils cause severe damage to residences, buildings, highways, pipelines, and other civil engineering structures. Strength and deformation parameters of soils are normally related to soil type and moisture. However, surprisingly limited focus has been directed to the compaction energy applied to the soil. Study presented herein is proposed to examine the effect of varying compaction energy of the engineering properties i.e. compaction characteristics, unconfined compressive strength, California bearing ratio and swell percentage of soil. When compaction energy increased from 237 KJ/m3 to 1197 KJ/m3, MDD increased from 1.61 g/cm3 to 1.75 g/cm3, OMC reduced from 31.55 percent to 21.63 percent, UCS increased from 110.8 to 230.6 KPa, and CBR increased from mere 1 percent to 10.2 percent. Results indicate substantial improvement in these properties. So, compacting soil at higher compaction energy levels can provide an effective approach for stabilization of expansive soils up to a particular limit. But if the soil is compacted more than this limit, an increase in swell potential of soil is noticed due to the reduction in permeability of soil.

Drained and Undrained Shear Behavior of Compacted Coal Wash

AbstractCoal wash is a granular waste material that is readily available in the vicinity of coal mining operations. While its potential use in structural fills has been recognized in the past, the effects of particle breakage on the geomechanical performance of the material have not been thoroughly investigated. In this paper, an experimental study on a selected coal wash is undertaken to characterize the influence of compaction and particle breakage on its corresponding stress-strain behavior. Particular emphasis is given to the role of compaction energy level and associated breakage incurred during compaction on the drained and undrained shearing behavior. The incidence of particle breakage for undrained and drained shearing was observed to be different, which in turn had a strong influence in the yielding behavior and the critical state. Furthermore, the critical state conditions for coal wash seem to be better described through a three-dimensional surface incorporating the effect of breakage.

Improvement of marginal lateritic soil using Melamine Debris replacement for sustainable engineering fill materials

This research evaluates the physical and mechanical properties of marginal lateritic soil and Melamine Debris (MD) blends as a sustainable engineering fill material. Physical property tests included specific gravity, water absorption, Atterberg limits, Los Angeles (LA) abrasion and particle-size distribution, while mechanical property tests included California Bearing Ratio (CBR) and swelling. The results indicate that MD as non-plastic coarse-grained and durable material (LA = 11.3%) can be used as an alternative replacement material for engineering fill materials. The MD replacement of lateritic soil reduces the fine content and increases the abrasion resistance of the soil particles, hence the reduction in liquid limit, plasticity index, LA abrasion and particle breakage. This physical property improvement leads to superior mechanical properties (soaked CBR and swelling) with increasing MD replacement ratio as compared to the soil alone. The proposed empirical equations for predicting soaked CBR and swelling of blends at different MD replacement ratios and compaction energy levels are useful in the selection of the suitable MD replacement to attain targeted mechanical property requirements. The physical and mechanical properties of the 20% MD replacement blend were found to meet the requirement of local road authority for engineering fill materials while the 50% MD replacement blend was at the borderline for a subbase course material.

Importance of Controlling the Degree of Saturation in Soil Compaction

In the typical conventional fill compaction, the dry density ρd and the water content w are controlled in relation to (ρd)max and wopt determined by laboratory compaction tests using a representative sample at a certain compaction energy level CEL. Although CEL and actual soil type affect significantly the values of (ρd)max and wopt, they change inevitably in a given earthwork project while CEL in the field may not match the value used in the laboratory compaction tests. Compaction control based on the stiffness of compacted soil in the field has such a drawback that the stiffness drops upon wetting more largely as the degree of saturation, Sr, of compacted soil becomes lower than the optimum degree of saturation (Sr)opt defined as Sr when (ρd)max is obtained for a given CEL. In comparison, the value of (Sr)opt and the ρd/(ρd)max vs. Sr - (Sr)opt relation of compacted soil are rather insensitive to variations in CEL and soil type, while the strength and stiffness of unsoaked and soaked compacted soil is controlled by ρd and “Sr at the end of compaction”. It is proposed to control not only w and ρd but also Sr so that Sr becomes (Sr)opt and ρd becomes large enough to ensue soil properties required in design.