Molding Water Content Research Articles

SUITABILITY OF RICE HUSK ASH TREATED BLACK COTTON SOIL FOR WASTE CONTAINMENT APPLICATION

This paper presents an experimental study aimed at assessing the suitability of rice husk ash (RHA) treated black cotton soil as a barrier in Municipal Solid Waste (MSW) containment facility. Laboratory tests were conducted on black cotton soil treated with 5, 10 and 15% RHA at moulding water contents of 2 and 4% on both wet and dry sides of optimum moisture content (OMC) using British Standard Heavy (BSH) compactive effort. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS), and unconfined compressive strength (UCS) tests were conducted on all the samples. The results obtained indicated that the soil was classified as A-7-5(18) according to the American Association of States Highway and Transport Officials (AASHTO) classification system and Silt of high plasticity (MH) in accordance with the Unified Soil Classification System (USCS). It was observed that addition of RHA was accompanied with decrease in the plasticity index from 24 to as low as 3%. An improvement in the moisture-density relationship of the soils showed an increase in Maximum Dry Density (MDD) from 1.46 to 1.52 Mg/m3 as well as a decrease from 24.5 to 21.2% in OMC. The increase in RHA contents up to 10% brought about an improvement in the strength of the soil specimens by almost 332.4kN/m2 at 2% on the dry side of OMC. The VSS decreases with increase in RHA content to achieve the minimum shrinkage strain of 4.1% at 5% RHA treatment.

Volume changes and mechanical degradation of a compacted expansive soil under freeze-thaw cycles

Expansive soils located in permafrost and seasonal frozen regions can easily suffer from the action of frost heaving and repeated freezing–thawing. When exposed to freeze–thaw (F–T) cycles, it may pose risk to civil engineering structures and thus causes heavy economic losses. In this study, a series of cylindrical expansive soil specimens were compacted at three different molding water contents (15%, 20% and 23%) and then subjected to a maximum of 12 closed–system F–T cycles. Besides, selected specimens compacted at the optimum water content were also tested under cyclic freezing–thawing with varying freezing temperatures (−5 °C, −10 °C and −20 °C). After each cycle of F–T, volume changes were measured and unconfined compression testing was also performed to estimate stress–strain behavior, resilient modulus and failure strength. Moreover, meso–structural analysis was conducted by using a simple optical test system to quantitatively extract the surface porosity and the pore orientation degree of expansive soil specimens after different F–T cycles. It is found that: 1) Volume changes for expansive soil specimens with higher and lower saturations present opposite directions and different magnitudes upon freezing, but show a similar trend of volume expansion after thawing. A moderate freezing temperature (i.e. –10 °C, in this study) has the greatest effect on volume changes. 2) Expansive soils tend to exhibit strain–softening behavior under unconfined compression conditions. The resilient modulus and failure strength decrease significantly at the first cycle of F–T and then reduce gradually to a stable value with increasing F–T cycles. The higher molding water content and a moderate freezing temperature will lead to a more pronounced degradation of mechanical behaviors with the F–T cycles. 3) It is suggested from the meso–structural analysis that the internal pores of expansive soils after a sequence of F–T cycles tend to become larger and more uniform, especially for the soil with higher water contents or experienced at a moderate freezing temperature.

Experimental Study on Tensile Strength of Undisturbed and Disturbed Sandy Soil Samples from Aguascalientes Valley, Mexico

This investigation presents the results of a comparative experimental analysis on the tensile strength obtained from soil samples in both conditions undisturbed and disturbed. For undisturbed soil samples, the tensile strength was obtained from an own-designed testing apparatus of direct tension. In this condition, the geometry of the samples during the carving process was designed to generate a failure plane in a predisposed area of the sample. For disturbed soil samples, a mold was built based on the used by Kim and Hwang (Eng Geol 69:233–244, 2003). Five types of stiff sandy soils from the Aguascalientes Valley, Mexico, were used as testing materials. For the analysis, the tensile strength obtained from undisturbed soil samples was compared with that of disturbed compacted samples within the mold, and at a dry density similar to that of their natural conditions. Three testing processes in disturbed samples were separately performed to obtain and analyze tensile strength. These include: (a) varying the molding water content; (b) completely saturating the samples and allowing them to dry at natural climatic conditions, until the water content was similar to the measured conditions in undisturbed soil samples; and (c) observing the variation in tensile strength on one type of soil when the water content was increased from 9.2%, which is the water content that corresponds to undisturbed samples at the moment of their testing. The results obtained from disturbed soil samples after a drying process were numerically more similar to the results of undisturbed soil samples, in large part because the drying process allowed the carbonated cementing substances of the soil to maintain the cohesion of the particles.

EFFECT OF COMPACTIVE EFFORTS ON DESICCATION – INDUCED VOLUMETRIC SHRINKAGE STRAIN OF SOME COMPACTED TROPICAL SOILS

This paper presents an experimental study of the desiccation-induced volumetric shrinkage strain for two compacted soils classified as A (A-6) and B (A-7-6)according to the Association of American States Highway and Transportation Officials (AASHTO) Classification System and CL according to the Unified Soil Classification System (USCS). The samples were prepared using three compactive efforts of Reduced Proctor (RP), Standard Proctor (SP) and Modified Proctor (MP) at moulding water contents relative to optimum (i.e. -2, 0, +2 and +4%). Samples were extruded from the compaction moulds and allowed to air dry in the laboratory in order to assess the variation of desiccation-induced shrinkage on the material with days and its potentials as a hydraulic barrier in waste containment applications. Results showed that soils compacted using the higher compactive effort showed lower values of volumetric shrinkage strain (VSS) due to the closer packing of soil fabric as a result of higher energy. Similarly, VSS increased with higher moulding water content for specimens compacted on the wet side of the optimum and contain much water as against the specimens compacted on the dry side of the optimum which had less water. At 7 and 14 days cured specimens using the RP compactive effort showed similar features, and up to 2% on the dry side of the optimum for 0 and 21 days cured specimens. The SP compactive effort for 7 and 14 days cured specimens yielded the peak dry densities at 2% on the wet side of optimum and at optimum. The MP compactive effort, the samples compacted at 2% on the wet side of optimum and 2% on the dry side of optimum showed similar behaviours for the hydration periods of 0 to 14 days curing period considering soil sample A. For soil sample B, at 14 and 21 as well as 7 and 21 days cured specimens showed highest dry densities with similar features for, 2% on the wet side of optimum up to the optimum; but changes at 2% on the dry side of optimum for both RP and SP compactive efforts respectively. The predicted models measured adequately the estimation of VSS value using the analysis of variance (ANOVA) and gave good indication of validity.

Saturated anisotropic hydraulic conductivity of a compacted lateritic soil

This study focuses on the saturated anisotropic hydraulic conductivity of a compacted lateritic clayey sandy soil. The effects of the molding water content and the confining stress on the anisotropic hydraulic conductivity are investigated. The hydraulic conductivity is measured with a flexible-wall permeameter. Samples are dynamically compacted into the three compaction states of a standard Proctor compaction curve: the dry branch, optimum water content and wet branch. Depending on the molding water content and confining stress, the hydraulic conductivity may increase or decrease. In addition, the results indicate that, when the samples are compacted to the optimum water content, lower hydraulic conductivity is obtained, except at a confining stress equal to 50 kPa. The increase of the confining stress decreases the hydraulic conductivity for each of the evaluated compaction states. In the wet branch, horizontal hydraulic conductivity is about 8 times higher than the vertical value. The anisotropic hydraulic conductivities of the dry and wet branches decrease when the confining stress increases, and the opposite is observed in the optimum water content state.

Effect of compaction conditions and fines content on cyclic undrained strength of saturated soils

This study investigates cyclic undrained strength of five types of sandy/silt soils that have various fines contents and are compacted at different combinations of molding water content and dry density. Results of conventional cyclic undrained triaxial testing of saturated compacted soils are compared. The study also investigates fabrics of the soil specimens compacted at different molding water contents using X-ray tomography imaging. The results show that the cyclic undrained strength properties are significantly influenced by the molding water content and dry density, but the trend differs depending on the fines content of compacted soils. In this paper, as a promising way to evaluate the cyclic undrained strength of compacted soils that have different fines contents and thus compaction properties, we describe the cyclic undrained strength as a function of the degree of saturation and dry density.

Evaluation of the Compressibility and Compressive Strength of a Compacted Cement Treated Laterite Soil for Road Application

This study presents experimental results of a laboratory investigation carried out on the compressibility, physical properties, compressive strength and microstructure of a cement–lateritic soil mixing. The investigation was conducted on a compacted fine grained lateritic soil, both untreated and treated with CEMII/BM 32.5 N cement (up to 9% by weight of dry soil), in order to evaluate the effect of cement content and curing time on the behavior of lateritic soil–cement mixtures compacted at modified proctor energy for various dry densities and molding water contents. Preliminary tests on cement amended soil showed improved physical properties. The unconfined compression tests show an increase of the unconfined compressive strength, reflecting an improvement of mechanical strength of the treated lateritic soil. The incremental oedometer tests showed that yield stress (σ′y) increased with both cement content and curing time, but decreased with increased molding water content. Reduction in modified compression index (Ccϵ) and modified recompression index (Crϵ) with increasing cement content and curing time was recorded for all tested water contents, the coefficient of consolidation (Cv) is increased for effective vertical stresses smaller than the yield stress. The results also show that it would be desirable that the soil sample is prepared at the dry side of optimum (ωDRY) when the optimum moisture content is not reached on the site. These positive impacts are mainly related to the fact that cement addition gives way to the formation of ettringite, calcite, portlandite and calcium silicate hydrates (afwillite and tobermorite) which derived principally from cement hydration.

Effect of Soil Parameters on Resilient Modulus Using Cyclic Tri-Axial Tests on Lateritic Subgrade Soils from Dakshina Kannada, India

Resilient modulus (Mr) of a soil is used as a basic input in the analysis of sub-grade and sub-base in the mechanistic empirical design approaches. The present work focuses on evolving a cost effective approach for the determination of resilient modulus in the laboratory based on tests performed using the CBR method, and the DCP. Lateritic sub-grades in India exhibit wide-ranging variations in strength and stiffness due to varying fines content, and other characteristics. Additionally, soils of lateritic origin with a higher proportion of fines, also called as lithomargic soils, pose difficulties to pavement engineers due to the poor supporting strength. In order to investigate the strength and stiffness of a wide variety of lateritic soils, it was proposed to perform tests on lateritic soils blended with lithomargic fines in this study. The study focuses on correlating the effect of grain-size, maximum dry-density (MDD), and optimum moisture content (OMC) on the resilient modulus (Mr) measured using the cyclic tri-axial test for various blends of lateritic soils. Tests were performed on soil samples compacted to MDD for molding water contents set to the OMC, dry-side of OMC, and the wet-side of OMC. The results indicated that an increase in the fines-content resulted in an increase in the OMC, and a decrease in the MDD and Mr values. Regressions were developed correlating the fines content to the resilient modulus. This study is expected to provide the necessary basis for estimating the strength of a wide variety of lateritic sub-grades based on the fines content.

PEMANFAATAN LIMBAH BATUBARA (FLY ASH) UNTUK BAHAN STABILISASI TANAH DASAR KONSTRUKSI JALAN YANG RAMAH LINGKUNGAN

Now days, Indonesia gets much the using of coal as alternative energy because increased of oil price and increased demand in the country. The expected production of coal in 2010 at about 230 million tons, where 68.5 million tons for local needs (45-46 million tons for electric power plant). Sumatera Selatan province is one of coal resources province in Indonesia and also has electric power plant have to promoted the utilizing of polluted material from electricity power plant. Industry electric coal power plant produced 5% polluted as fly ash and bottom ash, where 10-20% as bottom ash and as 80-90% fly ash. That polluted can be utilized as additives material  in soil stabilization for road construction.  This publication proposes an assessment of the utilization of lime, Portland cement (PC), fly ash as stabilizer of soft sub grades material in highway construction. The research conducts various contents of fly ash to different types of clay soils from various sites in Kuantan. The compaction tests and California Bearing Ratio (CBR) tests were applied in soil samples to estimate the optimum mixture design. The samples were set up by mixing soil samples with various content of fly ash and at optimum water content. The accomplishment of sub-grade stabilization depends on the engineering properties of soils and characteristic of additives. The laboratory result shows that the strength gain in stabilization mainly depends on two factors: additives content and molding water content. The variation content of fly ash and were 4%, 8% and 12% by total weight.Keywords: Sustainable, Engineering Properties of Soil, Soil Stabilization, CBR

EFFECTS OF SOIL RECOMPACTION ON PERMEABILITY

Presence of water changes the properties of soil such as dry density, shear strength, swelling-shrinkage and permeability. In this research, the effects of recompaction on permeability of laterite soil extracted from the Faculty of Engineering in Universiti Teknologi Malaysia was investigated in the design of liners and covers used as hydraulic barriers in sanitary landfills. Landfill liner needs to have sufficiently low permeability value so that it impedes migration of leachate through the compacted soil which causes groundwater contamination. The falling head permeability method of testing was adopted in the experimentation. Laterite soil samples were first mixed with water and compacted using Standard Proctor compaction. The same samples were then remixed at higher water contents and recompacted. The compacted and recompacted soil samples were subjected to falling head permeability tests. Based on the tests results, the permeability value of 2.24 x 10 -8 m/s for recompacted laterite soil at 40% moulding water content was lower than the permeability value of 5.95 x 10 -8 m/s for compacted sample at the same moulding water content. The laterite soil was observed to contain low fines content and is susceptible to crushing. Keywords: Permeability, Compaction, Laterite soil

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 soil parameters on modulus of resilience based on portable falling weight deflectometer tests on lateritic sub-grade soils

The use of portable falling weight deflectometers (PFWDs) has gained prominence among pavement engineers in the characterisation of soil sub-grade based on modulus of stiffness. The values of modulus of resilience and the corresponding values of the rebound deflection measured using the PFWD are largely influenced by the soil stiffness. The focus of the present investigation is on the study of the effect of soil parameters such as grain size distribution, maximum dry density (MDD) and optimum moisture content (OMC) on the values of modulus of stiffness (E PFWD ) obtained using the PFWD for tests performed on lateritic soil blends. Tests were conducted on various blends of lateritic soil samples compacted to MDD at moulding water contents set to the optimum moisture content (OMC), dry-side of optimum at OMC−3% and wet-side of optimum at OMC+3%. The regressions developed between the values of E PFWD and the percentage of fines and the percentage of sand for lateritic and lithomargic soils indicate a strong linear relationship between these variables for tests on un-soaked and soaked soils. The regressions developed will be of immense benefit to pavement engineers in estimating the values of the modulus of resilience for lateritic soils for the design of pavement sub-grades and embankments.

Mechanical Improvement of a Fine-Grained Lateritic Soil Treated with Cement for Use in Road Construction

AbstractThe mechanical strength of a fine-grained lateritic soil treated with CEMII/BM 32.5 N cement up to 9% by weight of dry soil and prepared at three different molding water contents was invest...

Hydraulic Conductivity of Compacted Granite Residual Soil Mixed with Palm Oil Fuel Ash in Landfill Application

Laboratory tests were carried out on compacted granite residual soil treated with 0 to 15% Palm Oil Fuel Ash (POFA), with a view to evaluate its hydraulic conductivity for its application in landfilling. The Soil–POFA mixtures were compacted using both Standard and Modified Proctors compactive efforts at 2% dry of Optimum Moulding water Content (−2%), at Optimum Moulding water Content (0%), at 2 and 4% on the wet side of Optimum Moulding water Content (+2 and +4%). The samples were permeated with water and the effect of moulding water content; compactive effort and POFA content were examined. The samples that met the minimum threshold of 1 × 10−9 m/s were used in plotting the acceptable zones criterion at various POFA mixtures. The results gave indications of reduction in the hydraulic conductivity values, with increase in compactive efforts, moulding water content and POFA content up to about 10%. This was the most suitable soil–POFA mixture for the hydraulic application.

Geotechnical Assessment of Crushed Shales from Selected Locations in Nigeria as Materials for Landfill Liners

Crushed shales obtained from two locations (Ahoko, Bida basin and Ifon, Dahomey basin) in Nigeria were evaluated to determine their suitability as compacted landfill liners. The shale samples were subjected to X-ray diffraction, hydraulic conductivity, classification, compaction, consolidation and cation exchange capacity tests. The result of the XRD revealed kaolinite and illite as the major clay minerals while quartz was the dominant non-clay minerals. The average CEC of Ifon and Ahoko shales was 5.37 and 8.34 mEq/100 g, respectively. The liquid limit, plastic limit and plasticity index of crushed Ifon shales ranged from (33.9 to 37.4%), (25.2 to 27.2%) and (8.6 to 10.2%) while the Ahoko shales ranged from (44 to 46.4%), (26.3 to 27.4%) and (16.6 to 19.6%), respectively. In addition, the estimated activity of the clay fractions of the two shales ranged from 0.41 to 0.51, suggesting inactive clays. The compacted shales have low compressibility and when compacted at modified Proctor level of compaction. At molding water content between optimum moisture content (OMC) ±2%, the hydraulic conductivities of the compacted shale were in the order of 10−6–10−7 cm/s when compacted at modified Proctor level. At OMC, hydraulic conductivities of the compacted shales were in the order of 10−7 cm/s when exposed to different concentration of calcium chloride solutions. Overall, the crushed shale samples from Ahoko and Ifon generally fulfilled the basic geotechnical properties for compacted clay liners.

Improvement of Bearing Ratio of Clayey Subgrade Using Compacted Flyash Layer

This paper presents a laboratory study on California Bearing Ratio (CBR) of flyash overlying a soft clay bed. Flyash sample (Class F) has been collected from Titagarh Thermal Power Plant situated near Kolkata. The type of soil collected locally is silty clay. Different configurations of soil and flyash overlying the soil have been maintained by varying the thickness ratio (ratio of thickness of flyash to that of clay) in the ratios of 1:2, 1:1 and 2:1. Both Standard Proctor and Modified Proctor compaction tests have been carried out to obtain respective maximum dry density and optimum moisture content to be used for CBR tests. The water contents of soil used in this study are 16, 22, 28, 34 and 40% where 16% is the optimum moisture content of the soil as obtained in Standard Proctor compaction test. Similarly water content of the soil has been kept at 12, 18, 24, 30, 36 and 42% for samples prepared using Modified Proctor energy where 12% is the corresponding optimum moisture content of soil. Improvement of CBR values of composite soil-flyash system has been observed when compacted flyash layer is placed above the compacted soil. Out of three thickness ratios tested, CBR value has been found to be the lowest at thickness ratio of 1:2 and the highest at 2:1. The improvement factor is found to be maximum for highest moulding water content irrespective of thickness ratio and compaction energy. It indicates the effective use of flyash soil composite matrix under worse affected condition of high water content. The paper highlights the nature of improvement of clayey soil when compacted flyash layer has been placed on it with different values of thickness ratio and placement moisture content and compaction energy.

Physicochemical and consolidation properties of compacted lateritic soil treated with cement

The consolidation of a fine-grained lateritic soil, treated with compound Portland cement (CEMII/BM 32.5N) up to 9% by weight of the dry soil and prepared at three different molding water contents (ωDRY, OMC, and ωWET), was investigated by means of a one-dimensional consolidation test. The physicochemical and microstructural properties of the compacted lateritic soil-cement mixture were investigated using Raman spectroscopy, polarized light microscopy (PLM), scanning electron microscopy (SEM), and pH measurement. The results show that cement admixtures resulted in the formation of tobermorite, afwillite, ettringite, portlandite, and calcite. However, tobermorite and afwilite, which are calcium silicate hydrates (CSH) whose mechanisms of formation are the pozzolanic and alkali silica reactions, appear from 6% added cement. The fixing point of the pH (12.4) is also obtained from 6% added cement. It is the threshold value at which the material begins to develop an adequate mechanical performance. In general, as the content of cement in the soil is increased, the yield stress increases from 1 to 3 times in comparison to untreated soil. For effective vertical stresses smaller than the cement-induced yield stress, the primary consolidation process for specimens treated with cement is 2–7 times faster than that for specimens not treated with cement, while for effective vertical stresses higher than the cement-induced yield stress, the primary consolidation process for specimens treated with cement is about 0.5–1.5 times faster than that for specimens not treated with cement. Permeability and secondary compression are reduced 1–9 times and 2–11 times that of the untreated samples, respectively. These changes are attributed to the creation of chemical bonds and aggregation that accompany the addition of cement. The results also show that it would be desirable for soil samples to be prepared at the dry side of optimum (ωDRY) when the optimum moisture content (OMC) is not reached at the site. These results indicate that significant and desirable changes in soil behavior can be achieved when the soil is admixed with CEM II/BM 32.5N cement, thus providing the possibility of using the tested lateritic soil in road construction.

Effects of pore fluid salinity on the collapsibility of low plasticity clay

This paper presents the results on the influence of pore fluid salinity on the Collapsibility of low plastic clay from Hashemite town, Jordan. Double odometer tests were carried out on natural specimens using pore fluids with different salt concentrations. The results indicate a considerable amount of collapse takes place for the sample with increasing the initial applied pressure on the sample regardless of the initial molding water content. However, the dry side of optimum sample shows larger collapse than that on wet side of optimum sample and vice versa. At low applied initial stresses, the higher the salts percentage in the sample, the larger the collapse occurs. Moreover, the amount of collapse tends to increase with increasing the applied pressure to reach a certain value for a given salts percentage, then the amount of collapse asymptotes to its maximum value or level off with increasing the pressure on the sample.

Hydraulic Conductivity of Fly Ash-Amended Mine Tailings

The objective of this study was to evaluate the effect of fly ash addition on hydraulic conductivity (k) of mine tailings. Mine tailings used in this study were categorized as synthetic tailings and natural tailings; two synthetic tailings were developed via blending commercially-available soils and natural tailings were collected from a garnet mine located in the U.S. Two fly ashes were used that had sufficient calcium oxide (CaO) content (17 and 18.9 %) to generate pozzolanic activity. Hydraulic conductivity was measured on pure tailings and fly ash-amended tailings in flexible-wall permeameters. Fly ash was added to mine tailings to constitute 10 % dry mass of the mixture, and specimens were cured for 7 and 28 days. The influence of fly ash-amendment on k of mine tailings was attributed to (1) molding water content and (2) plasticity of the mine tailings. Tailings that classified as low-plasticity silts with clay contents less than 15 % exhibited a decrease in k when amended with fly ash and prepared wet of optimum water content (w opt ). Tailings that classified as low-plasticity clay exhibited a one-order magnitude increase in k with addition of fly ash for materials prepared dry or near w opt . The decrease in k for silty tailings was attributed to formation of cementitious bonds that obstructed flow paths, whereas the increase in k for clayey tailings was attributed to agglomeration of clay particles and an overall increase in average pore size. The results also indicated that the effect of curing time on k is more pronounced during the early stages of curing (≤7 days), as there was negligible difference between k for 7 and 28-days cured specimens.

Stabilization Potential of Cement Kiln Dust Treated Lateritic Soil <sup></sup>

A dark reddish-brown lateritic soil collected from existing borrow pit abandoned by Reynold Construction Company Ltd behind New WAZOBIA Market on Latitude 08008′N and Longitude 04014′E along Ogbomoso-Ilorin Express road, Ogbomoso, Oyo State. Nigeria was treated with cement kiln dust (CKD), a by-product of long wet kiln, obtained from West African Portland Cement Organisation (WAPCO), Ewekoro, Ogun State, Nigeria, under varying moulding water content.The results show gradual reduction in the plasticity index of the samples, decrease in the maximum dry densities (MDD) with corresponding increase in the optimum moisture contents (OMC) of the treated soil samples. The unconfined compressive strength (UCS) of the treated samples increases with both increase in the treatment content as well as compactive effort from British Standard (BS) to West African Standard (WAS) however, there was reduction in the UCS with varying moulding water content as the water content increases and decreases relative to optimum moisture content. The maximum UCS was obtained at optimum moisture content.Cement kiln dust though regarded as waste can therefore serve as potential material in the stabilization of the lateritic soil when compacted at moisture content within its OMC.