Compaction Energy Research Articles

Effects of oil palm fibre ash on cement stabilised lateritic soil used for highway construction

ABSTRACT Increasing road construction activities in Nigeria has led to increased demand for lateritic soil (LS), whose properties vary from one location to another, and. The properties of some of this laterite deposits along road alignment can be improved to enable it withstand traffic loads. This paper presents results of the laboratory evaluation of LS stabilised with oil palm fibre ash and cement blends, with a view to determine its suitability as flexible pavement construction material. The mixtures were subjected to British Standard heavy (modified Proctor) compaction energy to determine their strength characteristics. Test results show that the properties of LS improved with oil palm fibre ash and cement treatment. The maximum dry density decreased with corresponding increase in optimum moisture content as the cement content increased from 0% to 6% and the LS content of the mixtures decreased with increased oil palm fibre ash, at a fixed per cent of cement. The peaked California bearing ratio of 190.09% (soaked) recorded for the 80% LS + 14% OPFA + 6% C mix proportion, with 14th day unconfined compressive strength of 785.75 kN/m2, cohesion of 140 kN/m2 and angle of internal friction of 25°, can be used as a base material in road construction. Further work may be encouraged to assess resilient modulus of this material under cyclic load.

Laboratory Methods for Assessing the Influence of Improper Asphalt Mix Compaction on Its Performance.

Compaction index is one of the most important technological parameters during asphalt pavement construction which may be negatively affected by wrong asphalt paving machine set, weather conditions, or the mix temperature. Presented laboratory study analyzes the asphalt mix properties in case of inappropriate compaction. The reference mix was designed for AC 11 S wearing layer (asphalt concrete for wearing layer with maximum grading of 11 mm). Asphalt mix samples used in the tests were prepared using Marshall device with the compaction energy of 2 × 20, 2 × 35, 2 × 50, and 2 × 75 blows as well as in a roller compactor where the slabs were compacted to various heights: 69.3 mm (+10% of nominal height), 66.2 mm (+5%), 63 mm (nominal), and 59.9 mm (−5%) which resulted in different compaction indexes. Afterwards the samples were cored from the slabs. Both Marshall samples and cores were tested for air void content, stiffness modulus in three temperatures, indirect tensile strength, and resistance to water and frost indicated by ITSR value. It was found that either insufficient or excessive level of compaction can cause negative effect on the road surface performance.

Potential Use of Sandy Mining Wastes as Raw Material in Road Construction

Sustainable programs are increasingly stimulating the use of industrial wastes, minimizing economic and environmental impacts. This use is especially notable in the mining industry, in which the amount of discarded material is exaggeratedly higher than the amount of obtained product. In this context, the aim of this paper is to study the sandy wastes generated from beneficiation processes of scheelite (CaWO4) to determine its potential use as a raw material in pavements. First, a physical, chemical and mineralogical characterization of the sandy wastes was performed. Subsequently, geotechnical characterization tests (grain size analysis, specific gravity, compaction, CBR and direct shear) were performed. The waste presented a heterogeneous mineralogical composition which is consistent with the mineralogical composition of the scheelite host rocks. The main minerals are calcite, quartz, micas and silicates of the garnet group and the pyroxene group that commonly occur in calcium-rich metamorphosed sediments. This resulted in a sandy and non-plastic material, positively influencing the geotechnical behaviour. The results show that the residual strength envelope exhibits zero cohesion for compaction energies, but the residual friction angle increases with the increasing energy. The values obtained for the strength parameters indicate that this material can be used as road embankment layers.

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.

Compactive Energy Level Effect on Strength of Fiber-Bentonite-Sand Mixture

Compactive Energy Level Effect on Strength of Fiber-Bentonite-Sand Mixture

Performance-based design of hard asphalt mixtures based on different compaction effort variable

Due to potential thermal cracking risks, marginal hard asphalt has not been widely used in China. A design method for hard asphalt under lower compaction levels was adopted in the present study with the aim of compensating for low-temperature cracking problems by increasing the asphalt content; simultaneously, the rutting resistance can still be maintained due to the high stiffness of hard asphalt itself. Four groups of asphalt, i.e. a control group (70# asphalt under Ndes = 75); two experimental groups (30# and 50# asphalt under Ndes = 50); and an analysis group (70# asphalt under Ndes = 50), were designed to evaluate the performance. Based on the experimental results, the conventional and this design method using 50# hard asphalt showed almost the same high- and low-temperature resistance. It is noteworthy that this method exhibited better fatigue resistance and increased fatigue life by approximately 1.6 times. In addition, this method also showed a larger dynamic modulus, especially under the traffic conditions of low frequency or high temperature. These results may indicate that a cheap marginal hard asphalt mixture under less compaction energy could achieve an even better performance than the conventional asphalt.

Strength Characteristics of Crushed Concrete and Carbide Wastes Stabilization of Clayey Soil as Highway Material

The functionality of a highway pavement is often judged by the quality and engineering properties of the soil-pavement structures and the materials used to improve the properties of these underlying soils. In this study, crushed concrete waste and carbide waste, whose associated disposal problems constitute environmental hazard, were used for the stabilization of clayey soil using British Standard heavy (Modified Proctor) compaction energy, and used as highway construction material. The various mixes were subjected to particles size analyses, specific gravity, moisture content, Atterberg limits, compaction characteristics, California bearing ratio, unconfined compressive strength test triaxial and water absorption tests. The test results show that the properties of the clayey soil improved with its stabilization with crushed concrete and carbide wastes. The maximum dry density decreased from 1.93 to 1.29 Mg/m3 with corresponding increase in optimum moisture content from 6.0 to 16.6 %, as carbide waste content increased, and crushed concrete waste and clayey soil contents of the mixtures decreased. The maximum California bearing ratio value of 55.01 % (unsoaked and soaked for 24 h) recorded for 25%CS + 75% (75%CCW + 25%CW) mix can be used as subbase material in flexible pavement construction. Further work may assess resilient modulus of this material under cyclic load.

Study of the Effect of Waste Glass Fibers Incorporation on the Collapsible Soil Stability Behavior

Soil collapse remains a major issue affecting structural foundations, particularly in arid and semi-arid zones where humidification is a key factor contributing to the collapse. Much research has been devoted to identifying treatment methods which enhance the stability and load-bearing capacity of this type of soil. This paper investigates the potential advantages of the addition of milled glass fibers (Fg ). Soil samples were prepared at different compaction energies and various water contents, then treated with different percentages of milled glass fiber, before being submitted to the simple consolidation odometer test. The results obtained in this study showed that soil samples treated with an optimal dosage of 6% of milled glass fibers compacted at 60 blows and humidified at 6% of moisture content. This represents an improvement in the stability of the soil, reducing the collapse potential (Cp) from 11.95% to 1.62%. This treatment method produces soil which can be classified as a moderate risk foundation soil according to the Jennings and Knight evaluation metrics (1975).
 Keywords: collapsible soils, arid zones, fiberglass, odometer test.

Effect of Discharge Energy of Magnetic Pulse Compaction on the Powder Compaction Characteristics and Spring Back Behavior of Copper Compacts

Magnetic pulse compaction (MPC) technology had unique compaction advantages compared to traditional powder compaction methods. In this study, the pure copper compacts have been consolidated by MPC technique. The effect of discharge energy on the microstructures, relative density, micro hardness, strain and stress of copper compacts were analyzed via optical microscopy, scanning electron microscopy, hardness tester and FEM simulation. The relationship between discharge energy and spring back was analyzed by numerical calculation. Results showed that the MPC method had the advantages to refine powder particles. The relative density of copper compacts reached 96% when the discharge energy was 9 kJ. Stress concentration was occurred at the upper edge of the powder body, and propagated to the upper center, lower edge and middle position of the powder body. The powder body could have a uniform strain distribution in a short period of time when the discharge energy was greater than 7 kJ. There was a linear relationship between the relative density and the logarithm of Vickers hardness. The axial and radial spring back both increased with the increase of discharge energy. When the discharge energy was 9 kJ, the axial and radial spring back was 2.36% and 0.42%.

CBR Laboratory Analysis for Determining The Number of Compaction Tracks to Achieve Field CBR

Compaction is the process of grounding the soil by removing air from the pores of the soil mechanically (beaten, crushed and so on) Compaction is carried out with the aim of improving the technical properties of the soil, namely obtaining the densest soil conditions (maximum solid state). In the process of compaction water content also plays a significant role to achieve maximum density value. Water is a lubricant for the soil to help unify the aggregate and remove air in the compaction process. From the results of compaction in the laboratory can be seen how much compaction energy is given and optimum water content (Wopt) to achieve maximum compaction. From the results of compaction in the laboratory can be applied for maximum compaction in the field, from the calculation of compaction energy in labour from the hammer weight of 4.5 kg, 45.7 cm falling height, g = 10 m/s2. The compaction energy is 1134 kg.m/s2. To get the number of compaction paths needed to achieve maximum compaction can be determined from the equipment used, the amount of energy used as an example of a vibro roller capacity of 10500 kg, get the solidification energy 164.1 (kg.m2/s). So the trajectory required vibro roller tool as much as seven trajectories.

Studies on properties of Flowable Earth Mix concrete for monolithic load bearing walls

The paper presents the results of experimental studies carried out on the properties of Flowable Earth Mix (FEM) Concrete. The FEM concrete can be used for the construction of monolithic load bearing walls in buildings. Smaller structures such as sanitary units, soak pits, water storage tanks etc. can also be built with single casting. Compared to the formwork and compaction energy used in monolithic rammed earth wall constructions, casting FEM concrete requires simpler formwork (minimising the cost of formwork) and minimum compaction energy for casting. The properties of FEM Concrete such as workability, compressive strength, flexural strength, drying shrinkage and moisture movements are discussed. The variables considered included type of soil, clay content of the mix and cement content. The results indicate the feasibility of producing monolithic FEM Concrete walls for load bearing buildings. It is easy to achieve required workability and strength of FEM Concrete through the mix design.

Evaluation of the Hydraulic Conductivity of Compacted Laterite-Metakaolin Mixtures for Solid Waste Leachate Containment

This paper presents the results of a study conducted to investigate the benefits of using metakaolin (MK) with laterite as liner material for containment of municipal solid waste (MSW). Laboratory tests were conducted on laterite specimens treated with MK at concentrations of 0 - 20 % by weight of the soil and compacted using four types of compaction energies. Hydraulic conductivity was determined based on permeation of the compacted laterite - MK mixtures with deionized water (DW) and municipal solid waste leachate (MSWL), respectively. Deionized water was the reference permeant fluid. The results showed that hydraulic conductivity generally decreased with increase in the percentage addition of MK to the soil. From an economic and sustainability point of view, it has been found from the results that 5 % MK can be added to soil and compacted at moulding water content of 14.1 % using the West African Standard (WAS) compaction energy to achieve the regulatory hydraulic conductivity of less than or equal to 1 x 10-9 m/s for compacted soil liner. The natural logarithm of the hydraulic conductivity experimental results were computed and used to develop regression equations for estimating hydraulic conductivity given MK contents and compaction energies. The results of the two-way analysis of variance (ANOVA) test carried out at 5 % level of significance showed that calculated F-statistics are statistically significant and the measured values of hydraulic conductivity compare well with the predicted values. The developed models can therefore be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Therefore, the developed models can be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Keywords ­_ Deionized water, Hydraulic conductivity, Leachate, Metakaolin, Municipal solid waste.

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.

Serviceability during asphaltic concrete production and leaching concerns of asphalt mixture prepared with recycled paper mill sludge

ABSTRACT The performance of an asphalt mixture does not only rely on its engineering properties. Yet, the service characteristics of an asphalt mixture do play an important role on the durability of pavements. This study was conducted to evaluate the effect of different aggregate types (granite and limestone) and the incorporation of recycled paper mill sludge (RPMS) on mixtures behaviour in terms of workability and compaction energy index (CEI). The effect of RPMS incorporation on the leaching potential was also assessed. A test was evaluated through the toxicity characteristics leaching procedure (TCLP) to identify the leaching behaviour of heavy metals with a possibility to contaminate the nearby water sources. Next, a surface morphological analysis was also conducted through the Scanning Electron Microscopy (SEM) to assess the relationship of fillers addition to the optimum binder content and water absorption. In this study, RPMS was used at rates of 0.5% and 1%. Based on the TCLP’s results, the leaching potential of RPMS incorporated mixture was addressed and proven to be less than the standardised requirements. The addition of different percentages of RPMS into limestone and granite asphalt mixtures had resulted in the increment of optimum binder content; however, still lower than control samples. Whereas their small increment in the combined water absorption percentage are relatively same to the control samples. The workability indices of asphalt mixtures peaked upon the usage of 0.5% RPMS but slightly reduced at 1% RPMS but nevertheless remained higher than the control specimen. This is due to the ability of RPMS reduce the surface tension, hence enabling less energy for compaction. The 0.5% RPMS addition was found to be the optimal content required to obtain a better service performance of asphalt mixture during mixing and compaction processes.

Influence of silica fume on mechanical and durability of pervious concrete

Anecdotal evidence has suggested that silica fume is beneficial for improving pervious concrete strength and durability. To determine how silica fume influences a variety of pervious concrete properties and durability the research presented herein studied the performance of paste and ultimately two types of pervious concrete. Since paste properties control pervious concrete workability, compaction, and ultimately performance, rheological properties of a series of paste mixtures with proportions and admixture dosages representative of field-placed pervious concrete were used to provide baseline behavior. Paste samples were continuously mixed and tested over time with the amount of silica fume replacing Portland cement up to 10%. The impact of silica fume on pervious concrete was first investigated on samples produced with a fixed compaction energy, as common in the field, using smooth river gravel aggregate. For pervious concrete produced with fixed compaction energy, changes in workability were reflected in void content which significantly impacted performance. Since void content and density changes significantly impacted performance, lastly samples were produced at a fixed void content using both smooth river gravel but also rougher limestone coarse aggregate. In fixed void content pervious concrete the compaction energy was varied to achieve a fixed void content of 20% for all samples. Results show around 5% silica fume produced the best performance of increased workability, strength and durability.

Modification Compression Strength of Test Machine by Using Control System on Compaction Energy

Soil compaction for specific construction is determined soil density tests. Several methods have been developed by previous researches and the prominent method is soil density. Several types of soil compaction method in the field, namely compaction method using vibration machine, impact, and pressure. In laboratories, soil compaction test was performed by using a hammer which uses human strength to solidify soil. An experimental investigation was conducted to explore a new modification related to compression strength test machine with energy compaction control system control system the energy of compaction. Researchers tried to design and make a soil compactor with a different mould measures from the standard Proctor method to modified method. The special of this new tool is that it can measure the compaction energy from each layer and dry density values. This research used different pressures as much as 1.67 N/mm2 - 20 N/mm2, every load conducted for sandy clay and silt samples. The values of dry density obtained from this research were between 1.59 kN/m3 - 1.68 kN/m3 and the value is higher compared with the value obtained from experiments using the Standard Proctor system. Meanwhile, the soil compaction results in the laboratory by using a new modification compression strength test machine with energy compaction control system can be an option of heavy equipment which can be used in the field.

Laboratory investigation on warm mix asphalt incorporating organo-silane additive

Warm mix asphalt (WMA) was developed to reduce asphalt production temperatures and energy consumption. Production of toxic gas emissions can be reduced considerably. However, lowered production temperature results in the presence of trapped moisture in the aggregates that could lead to stripping and subsequently moisture susceptibility problems, and which can be mitigated by using additives. Asphalt mixtures incorporating such additive must exhibit at least similar performance to conventional hot mix asphalts (HMA) which produce at higher temperatures. This paper evaluates the engineering properties and moisture susceptibility of asphalt mixtures incorporating Organo-Silane additive for use as WMA and anti-stripping agent. WMA samples were compacted at 125 °C and 115 °C and their performance were compared with control HMA specimens. The asphalt mixtures were prepared using similar aggregate gradation and binder types. Mixture workability was quantified in terms of the Compaction Energy Index (CEI) that was measured by integrating the area under the densification curve between gyration 8 and 92% theoretical maximum density. Lower CEI implies a more workable mixture. The CEI of WMA was 76.4, which was much less than the corresponding value for HMA. Samples were also tested for Marshal stability, resilient modulus and wheel tracking (WTT) tests according to ASTM D6927, ASTM D4123 and BS EN12697-22 procedures, respectively. The control samples perform better in the stability test. The resilient modulus of WMA was only about 10% lower compared to HMA. Resistance to permanent deformation was measured from the dynamic stability (DS) or the number of wheel passes per 1 mm rut depth over the last 15 minutes in a 60-minute tracking test. The DS of HMA, WMA compacted at 125 °C and 115 °C were 3138, 3044 and 2837, respectively. From the rutting resistance standpoint, the results are not significantly different. Hence, incorporation of the additive does not adversely affect mixture rutting resistance despite the lowered production temperature.

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.

Study on Characteristics and Application of High Plastic Clay Filling for In-service Highway

Clearing the engineering characteristics of high plastic clay and its engineering application are the basis for rational use of high plastic clay to fill the embankment. In this study, a series of water content tests, relative density tests, liquid and plastic limit tests, the grain size analysis tests, compaction and California Bearing Ratio (CBR) tests were carried out based on high plastic clay of diseased subgrade along west-section of Hainan Beltline Freeway. The relationships between CBR and water content, coarse particle content and compaction energy were studied. The results indicated that water content, coarse particle content, and compaction energy had significant effect on CBR, and water content is the main impact factor on CBR values. The maximum CBR water content was greater than the optimal water content by 4% to 5%. The performance of CBR and dry density had obvious distinction under different consistency and compaction energy. The equilibrium water content of high plastic clay subgrade during highway running period was near the plastic limit, which is 6% to 13% higher than the optimal water content. Base on the indoor test results, the problems related to the application of high plastic clay in subgrade filling were analyzed considering the characteristics of highway engineering and climate in Hainan province. It was concluded that high plastic clay could be directly used for embankment filling when the compaction energy conducted under the maximum CBR water content.