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Craig H. Benson - One of the best experts on this subject based on the ideXlab platform.
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estimating Optimum Water Content and maximum dry unit weight for compacted clays
Journal of Geotechnical and Geoenvironmental Engineering, 2000Co-Authors: Lisa R Blotz, Craig H. Benson, Gordon P BoutwellAbstract:An empirical method is described for estimating maximum dry unit weight (γdmax) and Optimum Water Content (wopt) of clayey soils at any rational compactive effort E. One variation of the method uses the liquid limit (LL) and one compaction curve, whereas the other uses only the LL. Linear relationships between γdmax and the logarithm of compaction energy (log E), and wopt and log E, both of which are a function of the LL, are used to extrapolate to different compactive energies. Data for 22 clayey soils were used to develop the method, and data for five additional soils were used for validation. Both variations of the method are unbiased and robust. The variation employing the LL and one compaction curve is slightly more precise, with typical errors of about ±1% for wopt and ±2% on γdmax. For the variation employing only the LL, typical errors are about ±2% for wopt and ±6% on γdmax.
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evaluation of excess foundry system sands for use as subbase material
Transportation Research Record, 2000Co-Authors: Jay R Kleven, Tuncer B. Edil, Craig H. BensonAbstract:Earthwork associated with highway construction provides an opportunity for high-volume reuse of excess system sands (ESS) discarded by the foundry industry. California bearing ratio (CBR), unconfined compressive strength, and resilient modulus tests were conducted on 13 ESS, one base sand, and two reference materials. Tests were conducted on specimens prepared dry of Optimum, wet of Optimum, and at Optimum Water Content with standard and modified Proctor compaction effort. Results of these tests were used to identify characteristic engineering properties of ESS, appropriate compaction conditions for ESS when used as subbase, and empirical equations that can be used to predict the engineering properties of ESS based on index properties. Results of the tests indicate that ESS classify as SP, SM, or SP-SM (A-2-4 or A-3 in AASHTO) and should be compacted dry or at Optimum Water Content and, if possible, with higher compactive effort. The CBR of the ESS ranged from 4 to 40 and averaged 20 when compacted with standard effort at Optimum Water Content. Swell during the soaking portion of the CBR tests was small for all ESS. ESS compacted at Optimum Water Content with standard effort had unconfined compressive strengths ranging from 71 to 190 kPa. Resilient moduli of the ESS were similar to that of a reference subbase material but smaller than a reference base material. A power function model in terms of bulk stress described resilient moduli of the ESS well.
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estimating Optimum Water Content and maximum dry unit weight for compacted clays technical note
Journal of Geotechnical and Geoenvironmental Engineering, 1998Co-Authors: Lisa R Blotz, Craig H. Benson, Gordon P BoutwellAbstract:An empirical method is described for estimating maximum dry unit weight and Optimum Water Content of clayey soils at any rational compactive effort E. One variation of the method uses the liquid limit (LL) and one compaction curve, whereas the other uses only the LL. Linear relationships between the maximum dry unit weight and the logarithm of compaction energy (log E), and the Optimum Water Content and log E, both of which are a function of the LL, are used to extrapolate to different compactive energies. Data for 22 clayey soils were used to develop the method, and data for five additional soils were used for validation. Both variations of the method are unbiased and robust. The variation employing the LL and one compaction curve is slightly more precise, with typical errors of approximately plus or minus 1% for Optimum Water Content and plus or minus 2% on maximum dry unit weight. For the variation employing only the LL, typical errors are approximately plus or minus 2% for Optimum Water Content and plus or minus 6% on maximum dry unit weight.
Mousa F. Attom - One of the best experts on this subject based on the ideXlab platform.
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THE USE OF CUTTING-STONE-SLURRY-WASTE IN ENGINEERING PRACTICE
2010Co-Authors: Mousa F. Attom, Magdi El-emamAbstract:The paper studies the use of cutting stones-Water-slurry-waste in engineering applications. Three types of selected clayey soils with different plasticity index and clay fraction were used. The initial physical properties of the clayey soils such as Atterberg’s limits, maximum dry density, Optimum Water Content, specific gravity, and clay fraction were evaluated in accordance with American Standard for Testing and Materials (ASTM) standard specification. Cohesion, angle of internal friction and unconfined compressive strength were evaluated from samples remolded at 95% relative compaction and Optimum Water Content. Two sets of soil samples were prepared for testing purpose in this investigation. The first set is prepared with fresh Water at different initial Water Content and dry densities and without any admixture. The second set is identical to the first set but the Water Content is replaced with the same percentage of stones slurry waste (SSW). The two sets of samples were tested for the unconfined compressive strength at two different percentages of Water Content (first set) and cutting stones slurry (second set) and at three different initial dry densities. Additionally, the effect of mixing the soils with cutting stone slurry waste on the plastic index, dry densities and Optimum Water Contents were studied. Results indicated that mixing the clay soil with cutting stone slurry waste increased the max dry density, and decreased the Optimum Water Content percent and the plasticity index. Also, both unconfined compressive strength and the modulus of elasticity of the soil was improved significantly due to the addition of stone slurry waste to the tested soil.
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Influence of heat treatment on the behavior of clayey soils
Applied Clay Science, 2001Co-Authors: Majed Abu-zreig, Nabil M. Al-akhras, Mousa F. AttomAbstract:Abstract This study examines the effect of temperature under laboratory conditions of three clayey soils collected from northern Jordan. Soils were subjected to four temperature levels, i.e. 100, 200, 300 and 400 °C. Various soil properties were studied including Atterberg limits, particle size distribution, Optimum Water Content, maximum dry density, swelling potential, and unconfined compressive strength. Experimental results revealed that heat treatment higher than 100 °C resulted in a decrease in liquid and plastic limits, Optimum Water Content, unconfined compressive strength, and swelling pressure of soils tested. However, maximum dry density increased slightly with an increase in temperature to reach a maximum value of 14.3 kN/m 3 at 400 °C for soil-1 compared to 12.9 kN/m 3 at ambient temperature. Heating the clayey soils at 400 °C decreased the liquid limit, plastic limit, Optimum Water Content, swelling pressure, and unconfined compressive strength by 80%, 100%, 65%, 94%, and 100%, respectively, in average compared to soil specimens at ambient temperature.
Fusao Oka - One of the best experts on this subject based on the ideXlab platform.
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study of dynamic stability of unsaturated embankments with different Water Contents by centrifugal model tests
Soils and Foundations, 2015Co-Authors: Yosuke Higo, Chungwon Lee, Tatsuya Doi, Teppei Kinugawa, Makoto Kimura, Sayuri Kimoto, Fusao OkaAbstract:Abstract It has been pointed out that the damage to unsaturated embankments caused by earthquakes is attributed to the high Water Content brought about by the seepage of underground Water and/or rainfall infiltration. It is important to study the effects of the Water Content on the dynamic stability and deformation mode of unsaturated embankments in order to develop a proper design scheme, including effective reinforcements, for preventing severe damage. This paper presents a series of dynamic centrifugal model tests with different Water Contents to investigate the effect of the Water Content on the deformation and failure behaviors of unsaturated embankments. By measuring the displacement, the pore Water pressure and the acceleration during dynamic loading, as well as the initial suction level, the dynamic behavior of unsaturated embankments with an approximately Optimum Water Content, a higher than Optimum Water Content, and a lower than Optimum Water Content, are discussed. In addition, an image analysis reveals the displacement field and the distribution of strain in the embankment, by which the deformation mode of the embankment with the higher Water Content is clarified. It is found that in the case of the higher Water Content, the settlement of the crown is large mainly due to the volume compression underneath the crown, while the small confining pressure at the toe and near the slope surface induces large shear deformation with volume expansion.
N.r.a Bird - One of the best experts on this subject based on the ideXlab platform.
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Methods for predicting the Optimum and the range of soil Water Contents for tillage based on the Water retention curve
Soil and Tillage Research, 2001Co-Authors: A.r Dexter, N.r.a BirdAbstract:Abstract Information is needed on the range of soil Water Contents for tillage. The objective of the work was to develop methods for the prediction of the soil Water Contents at which tillage may be done satisfactorily. Three Water Contents are considered: the lower (dry) limit, the Optimum Water Content, and the upper (wet) limit. This paper makes a synthesis of published results from tillage and soil physics experiments and also includes some new experimental results. The effects of tillage are considered in relation to some “fixed points” including the lower plastic limit, field capacity and a new fixed point “the inflection point”. These considerations lead to methods for prediction of the lower (dry) tillage limit, the Optimum Water Content, and the upper (wet) tillage limit in terms of the parameters of the van Genuchten equation for soil Water retention. Predictions can be made in terms of soil composition through the use of pedotransfer functions for the parameters of the van Genuchten equation. The new methods will enable the effects of soil degradation and climate change on tillage work days to be estimated. The results are potentially mappable using geographic information systems.
Márta Birkás - One of the best experts on this subject based on the ideXlab platform.
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Prediction of the soil structures produced by tillage
Soil and Tillage Research, 2004Co-Authors: Anthony R. Dexter, Márta BirkásAbstract:Data are presented for the amount of clods >50 mm produced when five different soils were tilled at a range of different, naturally occurring Water Contents. The Optimum Water Content for soil tillage is defined as that at which the amount of clods produced is minimum. The amount clods produced at this Optimum Water Content is shown to be linearly and negatively correlated with the value of Dexter's index S of soil physical quality. This results in a rational model for soil tillage that enables predictions to be made for all different soils and conditions. Pedo-transfer functions can be used to estimate the input parameters for the model for cases, for which measured values are not available. It is concluded that for soils with good physical condition (i.e. S > 0.035), no clods >50 mm are produced during tillage.
