Maximum Dry Density Values Research Articles

IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF EXPANSIVE SOILS USING CEMENT

Expansive soils are distributed in many regions in world. (including Iraq),particularly in semiarid regions with alternating wet and dry seasons. Therefore, it is necessary to study the geotechnical properties of such soils due to the possible large damage of structures founded and constructed on this soil. The soil used in this research is from Abu-Ghreab site.This paper reports the outcome of an investigation into the effect of cement on geotechnical properties of expansive soil, to ascertain its suitability for use as a modifier or stabilizer in the treatment of the soil. Classification, consistency indices, specific gravity, compaction, direct shear, and swell percentage and swell pressure tests, were conducted on specimens of expansive soil. Results of tests showed that the soil was a CH soil, according to the USCSclassification system.Liquid limit , plastic limit and plasticity index are reduced by adding 8% of cement , at optimum moisture content the maximum dry density value increase with increase the percentage of cement adding to the expensive soil and conducting direct shear test, an obvious increase is noticed in the amounts of cohesion (C) and internal friction angle (Ø) .While swell percentage decreases by adding cement and while the swell pressure decreases to the half of its original values.

Effects of Compaction Effort on Compaction Behavior and Particle Crushing of a Crushed Sandstone-Mudstone Particle Mixture

The present study focuses on the effects of compaction effort on the compaction behavior and particle crushing of a mixture of crushed sandstone particles and mudstone particles. Compaction tests under five different compaction efforts on the mixture were performed. Testing results indicate that the values of the maximum dry density and the average relative breakage of the mixture are nonlinearly increasing with the increase of the compaction effort, but the variation of the optimum moisture content is independent of the increase of the effort. Compared to a crushed sandstone particle mixture with the same grain size distribution and the same compaction effort, the maximum dry density of the crushed sandstone-mudstone particle mixture may be increased, the optimum moisture content reduced, and the average relative breakage during compaction reduced too, by the mixing of a small quantity of mudstone particles.

Effect of Lime and Waste Stone Powder Variation On the pH Values, Moisture Content and Dry Density of Clayey Soil

This paper reports an investigation of the influence of waste stone powder and lime on the geotechnical properties of clayey soil. The compaction and changes in the chemical properties of the soil with pH test when mixed with varying proportions of waste stone powder and lime were investigated. Thus, the effectiveness of using Waste Stone Powder (WSP) and lime for preliminary laboratory tests including grain size analysis, PH test and standard Proctor compaction tests for stabilizing fine-grained clayey soil (CL) was investigated in the laboratory. The percentage of lime and WSP used on the samples varied from 0 to 11%, which treatment of the samples with lime and WSP content show that the optimal moisture and maximum dry density values of the samples were changed. The results show increasing in the pH value of clayey soil with increasing amount of waste stone powder and lime. And the optimal moisture content increased with increasing lime and WSP content for all the samples. Also the maximum dry density decreased with increasing lime, whereas the maximum dry density increased with increasing WSP content. The behavior of the geotechnical properties of the clayey soil when blended with waste stone powder and lime indicates that these materials are a good modifier for this soil.

EFFECT OF LIME AND STONE DUST IN THE GEOTECHNICAL PROPERTIES OF BLACK COTTON SOIL

In the present study Black Cotton Soil was stabilized with a mixture of lime and Stone Dust. First an optimum value of lime was determined on the basis of some geotechnical properties of mixture of lime and Black Cotton Soil. Then Stone Dust was mixed upto 25% by weight with an increment of 5% in the optimized mixture of lime-Black Cotton Soil. California bearing ratio, unconfined compression strength and maximum dry density values were determined of these modified mixes. Morphology of the soil and admixture has been studied by Scanning electron microscope (SEM), while mineralogical composition has been determined by X-Ray diffraction technique (XRD).

Compaction Characterization and Model Prediction of Stabilized UnyegheResidual Soils, AkwaIbomState Nigeria

The primary step in the construction of sub- base and base course materials is the identification and selection of suitable borrow pits. This is done by obtaining samples from economically feasible borrow pits and testing them in the laboratory. 1 The laboratory compaction with varying compactive effort viz: British Standard (BS) compaction with 2.5kg rammer, repeated on 3 layers of 61 blows each, West African Standard (WAS) compaction with 4.5kg rammer repeated on 5 layers of 25 blows each; and Heavy British Standard (HBS) compaction with 4.5kg rammer repeated on 5 layers of 61 blows each on samples from locations 1 and2 respectively were conducted. Focus was on Unyeghe residualsoils from two distinct borrow-pits stabilized with river sand and ordinaryPortland cement. In all cases, the rammers fell from a height of 450mm above the top of mould. The unsoakedCBRvalues obtained with BS and WAS compactions,34% and 46% respectively,were far below the recommended minimum of 35% and 80% for sub-base and base courses applications by FMW & H 2 (1997) specification.The HBS compaction tends to simulate the actual field condition by limiting the air voids to about 5%. An interesting feature observed is that the highest CBR and MDD values obtained, (132%, 134% and 2100kg/m 3 , 2010kg/m 3 ) occurred at lower moisture contents (7.6%, 9.4%) at both locations. On application of the BS and WAS compactive effort to OPC stabilized Unyeghe residual soil samples the soaked CBRand MDD values at optimal level(124%, 132% and 2000kg/m 3 , 2060kg/m 3 ), showed comparative improvement. This result could not be justified only by direct influence attributable to the stabilizing materials only. It could thus be concluded that both the California Bearing Ratio (CBR) and Maximum Dry Density (MDD) while not being inherent properties of the soil material, are predicated on the applied compactive effort. Hence, the more the soil material is compacted, the greater the value of cohesion and shearing resistance. Multiple nonlinear regressed models were developed for the purpose of prediction and optimization of Unyeghe residual soils with various stabilizing parameters.

Predictive Shear Strength Models for Tropical Lateritic Soils

This research focused on the indirect determination of soil shear strength using basic soil properties for a lateritic soil area. Samples were collected from six different locations in the Federal University of Technology Akure, Ondo State, Nigeria. These lateritic soils fall within the A-2, A-6, and A-7 groups in the AASHTO classification system. Exploratory analysis of the six independent variables was performed using the statistical analysis of principal components. The stepwise multiple regression was used to establish the best predictive models for the California bearing ratio (CBR) and undrained shear strength (). A remarkable significant model for undrained shear strength [] with ( = 229.476, , Adjusted = 0.989, Std. Error = 7.5638) emerged. This model accounts for 99.4% of variation in the dependent variable. For the included predictor variables beta = 0.722, and beta = −0.417, for MDD and GI, respectively, where other variables are excluded from the model. This makes a quick evaluation of the shear strength of lateritic soils by using their maximum dry density and group index values possible.

Mechanical-Cement Stabilization of Laterite for Use as Flexible Pavement Material

An attempt was made to improve the physical and strength properties of a reddish-brown lateritic soil. 15–60% of sand by dry weight of laterite was used as a modifier in the stabilization of the laterite with 3–12% by dry weight of cement. Classification, compaction, California bearing ratio (CBR), and unconfined compressive strength tests were carried out on the specimens. The plasticity index decreased from 17% for untreated laterite to 2.5% when treated with a combination of 60% sand+6% cement . For the two energy levels of compaction, optimum moisture content (OMC) was found to increase with an increase in cement content but decreased as the sand content increased. The OMC at the West African standard (WAS) energy level was consistently lower than the values obtained at the standard proctor (SP) energy level, while the corresponding values of maximum dry density were higher at the WAS energy level than the values at the SP energy level. The CBR requirements for base course material were met when later...

The Suitability Of Tarsand As A Stabilizing Agent For Lateritic Soils

The suitability of tarsand as a stabilizing agent for lateritic soils was investigated in this study. This is to find a rather cheaper means of stabilizing lateritic soils that has become very important for the construction industry. The soil samples were subjected to the general classification and strength tests. The strength tests are: the compaction, unconfined compression and California Bearing Ratio (CBR). Tarsand was introduced as stabilizer in 0, 2, 4, 6, 8 and 10 percentages. The CBR, Maximum Dry Density (MDD) and unconfined compression values all decreased with increasing tarsand contents. For example, MDD reduced gradually from 1919 kgm-3 at 0% tarsand content to 1765 kgm-3 at 10% tarsand content, while CBR also reduced gradually from 21.0% at 0% tarsand content to 3.40% at 10% tarsand content. These results showed that tarsand is not a suitable stabilizing agent for lateritic soils, especially in the strength assessments. IFE Journal of Science Vol. 9 (2) 2007 pp. 215-218

Artificial Neural Network Prediction Models for Soil Compaction and Permeability

This paper presents Artificial Neural Network (ANN) prediction models which relate permeability, maximum dry density (MDD) and optimum moisture content with classification properties of the soils. The ANN prediction models were developed from the results of classification, compaction and permeability tests, and statistical analyses. The test soils were prepared from four soil components, namely, bentonite, limestone dust, sand and gravel. These four components were blended in different proportions to form 55 different mixes. The standard Proctor compaction tests were adopted, and both the falling and constant head test methods were used in the permeability tests. The permeability, MDD and optimum moisture content (OMC) data were trained with the soil’s classification properties by using an available ANN software package. Three sets of ANN prediction models are developed, one each for the MDD, OMC and permeability (PMC). A combined ANN model is also developed to predict the values of MDD, OMC, and PMC. A comparison with the test data indicates that predictions within 95% confidence interval can be obtained from the ANN models developed. Practical applications of these prediction models and the necessary precautions for using these models are discussed in detail in this paper.

Laboratory Characterization of Recycled Concrete for Use as Pavement Base Material

The purpose of this research was to characterize both demolition and haul-back sources of recycled concrete material (RCM) available in Utah County, Utah, for use as pavement base material and to investigate the self-cementing behaviors of each. A telephone survey was conducted to assess the state of the practice with respect to the local use of RCM, and extensive laboratory testing was performed to evaluate the strength and durability properties of both sources of RCM. Laboratory testing included determinations of particle-size distributions, Atterberg limits, specific gravity values, absorption characteristics, moisture–density relationships, California bearing ratio (CBR), unconfined compressive strength (UCS), stiffness, resistance to freeze–thaw cycling, tube suction test (TST) moisture susceptibility classifications, and Los Angeles abrasion losses. The results of the testing indicate that marked stiffening and strength gain of the materials occur within a 7-day curing period, although the rate and extent of the increases are dependent on the material source. The higher fines content of the haul-back material corresponded to higher absorption, optimum moisture content, maximum dry density, CBR, UCS, and stiffness values compared with the demolition material, presumably because of the exposure of greater quantities of unhydrated cement in the production of the haul-back RCM. However, the haul-back RCM was characterized by a greater loss in stiffness after freeze–thaw cycling and received a marginal moisture-susceptibility rating in the TST, while the demolition RCM was rated as non-moisture-susceptible. Further research is needed to more definitively investigate the self-cementing mechanism of RCM.

The Suitability of Tarsand as a Stabilizing Agent for Lateritic Soils

The suitability of tarsand as a stabilizing agent for lateritic soils was investigated in this study. This is to find a rather cheaper means of stabilizing lateritic soils that has become very important for the construction industry. The soil samples were subjected to the general classification and strength tests. The strength tests are: the compaction, unconfined compression and California Bearing Ratio (CBR). Tarsand was introduced as stabilizer in 0, 2, 4, 6, 8 and 10 percentages. The CBR, Maximum Dry Density (MDD) and unconfined compression values all decreased with increasing tarsand contents. For example, MDD reduced gradually from 1919 kgm-3 at 0% tarsand content to 1765 kgm-3 at 10% tarsand content, while CBR also reduced gradually from 21.0% at 0% tarsand content to 3.40% at 10% tarsand content. These results showed that tarsand is not a suitable stabilizing agent for lateritic soils, especially in the strength assessments. IFE Journal of Science Vol. 9 (2) 2007 pp. 215-218

Soil Properties And Pavement Performance In The Nigerian Rainforest: A Case Study Of Shagamu-Benin Road, South-Western Nigeria

The geotechnical properties of the sub-structure of the Shagamu-Ore-Benin pavement were studied in an attempt to identifying the quality of construction materials and the pavement performance. The sub-structure soil materials were collected from the field and were taken to the laboratory for particle size analysis, Atterberg limit test, compaction test and strength test. The soils were classified using Unified Soil Classification System (USCS) and American Association of State Highway Official (AASHO). The soils were mainly clayey sand (SC) and A-7-6. The maximum dry density (MDD) and optimum moisture content (OMC) values range from 1.68 Mg/m3 to 2.30 Mg/m3 and 9.0% to 17.5% respectively. The widespread failed sections on the road are as a result of very fine grained silt/clay fraction (>30%), high water table, poor drainage and sub-standard construction materials. A well compacted sub-base and sub-grade crushed stone base course and good drainage would ensure good performance of the road. Key words: Soil, pavement, failure, geotechnical, performance Ife Journal of Science Vol. 7 (1) 2005: 119-122

The Use of Brackish and Oil-Contaminated Water in Road Construction

This paper discusses the use of non-freshwater, including brackish groundwater and oily production water, in road construction. Non-freshwater was obtained from four major oil production fields in Oman. First, chemical analyses were carried out on nine non-freshwater types, including tap water, obtained from the four sites. These water types were then used with well-graded sand (WGS), high-plasticity silt (HPS), and a road base material to evaluate water effect on material properties. Atterberg limits, compaction, California Bearing Ratio (CBR), swell percentage, swell pressure, and direct shear tests were performed. Results show that there is a slight decrease in the liquid limit when non-freshwater is used. Non-freshwater resulted in a slight decrease in optimum moisture content and a slight increase in maximum dry density in WGS, whereas with HPS it caused slight decreases in optimum moisture content and maximum dry density values. There was an increase in CBR when non-freshwater was used with WGS and HPS soils. However, the use of production water caused a decrease in CBR values for WGS. For the road base material, the use of non-freshwater generally caused a decrease in CBR. The swell pressure tends to increase when non-freshwater is used with HPS. For the road base material, there is a decrease in cohesion and an increase in friction angle when non-freshwater is used in lieu of tap water. Promising laboratory results indicate the potential use of brackish and oily water types in road construction.

An Examination of the Use of Lime and Pulverized Fly Ash to Stabilize Clay Materials

Clay soils frequently present difficulties in construction operations. One of the means by which the engineering behaviour of clays can be improved is to stabilize them by the addition of cementitious materials. However, one of the problems with stabilization of clay soils is their range of mineralogical composition, which means that some are more easy to stabilize than others. In order to investigate this problem, three of the principal components found in clays, namely, kaolinite, montmorillonite and quartz, were chosen. These three components were treated with varying amounts of lime and pulverized fly ash (PFA). As stabilization of clay soils has most frequently been used in relation to road construction, the soil materials were subjected to the types of tests used in the design procedure for road pavements, namely, Atterberg limit tests, compaction tests, California bearing ratio tests, unconfined compressive tests, and tests to determine Young's modulus. Samples for testing, except those for consistency limits, were prepared with optimum values of moisture content and maximum dry density and were cured for different periods of time. The results of the various tests were compared, especially to see if there was an optimum amount for a particular addition which would bring about maximum enhancement of engineering performance of the components concerned. In all cases lime gave a greater enhancement in the soil property concerned than did PFA. When mixtures of lime and PFA were used, that with the highest lime ratio gave the best improvement.

Multi-cyclic influence on standard laboratory compaction of residual soils

Standard laboratory compaction tests (e.g., BS, AASHTO, WA) originally designed to simulate and control compaction in field earthworks have fallen short of achieving their stated objective. Several reasons have been advanced to explain this, but the most important, which is advanced here, is the multiple recycling or multi-cyclic compaction of soil samples (at least five times per test) involved in almost all these standard tests. This recycling has been observed from a previous study to fall within the zone of influence of multi-cyclic compaction. This paper, therefore, investigates the influence of multi-cyclic compaction on the maximum dry density ( MDD) and optimum moisture content ( OMC) of some deltaic lateritic soils (derived from deltaic sedimentary deposits) that are currently being used for the construction of many road embankments in the Port Harcourt area of eastern Nigeria. Samples of these soils were subjected to standard Proctor and break-up Proctor (similar procedure to standard Proctor but with a fresh batch of soil used for each point on the density-moisture curves) compaction tests. The standard tests were observed to underestimate the MDD values, albeit with a decreasing influence as the depth of sampling/extraction increased. This effect was minimised at a depth of around 5.0 m. In addition, differences in dry densities obtained from both methods were observed to maintain, fairly well, fourth-order polynomial relationships with the corresponding moisture contents through computer-aided statistical analysis. Also, this relationship was employed to present a model — in the form of a family of curves — from which the more reliable break-up densities could be predicted from the less tedious, and hence more popular, standard tests.

Some geotechnical properties of residual mica schist derived subgrade and fill materials in the Ilesha area, Nigeria

Fine grained micaceous soils are known to be relatively difficult to densify by compaction, and they may pose subsequent stability problems to pavement structures constructed over them if appropriate caution is not exercised during the construction period. The texture, consistency. compaction and CBR characteristics of the mica schist derived lateritic soils in the Ilesha area were studied for a critical evaluation of the long term performance of soils which have been used as borrow materials in the construction of stretches of the Ife-Akure highway. X-ray diffraction studies confirm that the main clay mineral present is kaolinite, but it is associated with various amounts of illite, montmorillonite and chlorite. Densification by compaction was observed to be relatively inhibited when the maximum dry density values are compared with those of other lateritic soils occurring in the same locality. Soaked CBR values are low, ranging from 6% to 14% only. Textural considerations disqualify the soils as borrow material, but surprisingly, the consistency limit values make them tolerable.