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P C Lambe - One of the best experts on this subject based on the ideXlab platform.
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Resilient Modulus measurement of fine grained subgrade soils
Transportation Research Record, 1999Co-Authors: A S Muhanna, M S Rahman, P C LambeAbstract:The effects of several variables that may influence the Resilient Modulus of fine-grained subgrade soils have been studied using two different soils. The number of load applications, the rest period, and the load sequence are shown to have no significant effect on the measured Resilient Modulus. It is also demonstrated that confining pressure in the range of 0 to 69 kPa (0 to 10 psi) has less than a 5 percent effect on the measured Resilient Modulus of the investigated soils. However, the condition of specimen ends is shown to influence the measured Resilient Modulus. A comparison between the measured Resilient Modulus for both soils using impact and kneading compaction methods is also presented.
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model for Resilient Modulus and permanent strain of subgrade soils
Transportation Research Record, 1998Co-Authors: A S Muhanna, M S Rahman, P C LambeAbstract:The Resilient Modulus and cumulative permanent strain of subgrade soils under anticipated repeated loading are important considerations for the design of a pavement against fatigue and rutting failures. A simple model was developed to evaluate the Resilient Modulus and accumulated permanent strain of cohesive subgrade soils under repeated loads. The empirical model was derived from the observed behavior of an A-6 cohesive soil. The model was tested against an A-5 soil. The proposed model was found to predict adequately the Resilient Modulus and the accumulated plastic strain for all A-6 and A-5 specimens with 90 percent confidence intervals of 0.61 and 1.4, and 0.66 and 1.39, respectively.
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laboratory determination of Resilient Modulus for flexible pavement design
NCHRP Web-Only Document, 1997Co-Authors: R D Barksdale, P C Lambe, J Alba, N P Khosla, R Kim, M S RahmanAbstract:Extensive diametral repeated load tests were performed on asphalt concrete specimens. Extensive repeated load triaxial tests were performed on base and subgrade materials. New Resilient Modulus test methods were developed for these materials and presented in the form of American Association of State Highway and Transportation Official (AASHTO) type test procedures. The repeated load test is not easy to perform and must be carried out on a carefully calibrated testing system including using synthetic specimens. To minimize human errors, a fully automated, closed loop testing and data acquisition system should be used. For asphalt concrete, the Strategic Highway Research Program (SHRP) Load Guide diametral testing device should be employed to minimize rocking. A mountable extensometer provides less variance and hence better repeatability for Resilient Modulus measurement. Poisson's ratio can be evaluated using a surface mounted linear variable differential transformer (LVDT) to measure vertical deformation and externally mounted LVDTs to determine horizontal deformation. The value of Poisson's ratio used to determine the Resilient Modulus has an important influence on its value. Poisson's ratio should be measured rather than assumed. To reliably determine Resilient Modulus, axial deformation of base and subgrade materials should be measured on the specimen using either (1) an optical extensometer, (2) non-contact proximity gages or (3) small LVDTs supported by lightweight clamps. The optical extensometer is highly recommended. For granular materials a vacuum triaxial test offers an excellent approach when an optical extensometer is used. An unconfined repeated load test is recommended for cohesive subgrade soils. For cohesive soils, bedding irregularities at specimen ends, specimen aging and soil structure must all be properly considered to obtain reliable Resilient moduli.
Murad Abufarsakh - One of the best experts on this subject based on the ideXlab platform.
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using artificial neural network and genetics algorithm to estimate the Resilient Modulus for stabilized subgrade and propose new empirical formula
Transportation geotechnics, 2020Co-Authors: Shadi Hanandeh, Allam Ardah, Murad AbufarsakhAbstract:Abstract This paper presents the results of using rigorous modeling artificial neural network and genetic algorithm to examine the proper stabilization of very weak subgrade soils at high moisture contents. The experimental database was performed in Louisiana transportation research center for four types of soft soil, 125 samples data were prepared and used in development ANN and genetic algorithm models. For two models, the input variables include eight parameters, namely cement percentage, lime percentage, PI, silt percentage, fly ash, optimum moisture content OMC, moisture content M.C, and clay percentage, the output variable includes Resilient Modulus for different types of stabilized subgrade. Furthermore, mathematical models were proposed to predict the Resilient Modulus for stabilized weak subgrade with different types of stabilizer agent such as cement, lime, and fly ash with four different subgrade soil types of different plasticity indices. Besides, the proposed models for estimating Resilient Modulus for stabilized subgrade were derived by an artificial neural network model and genetic algorithm. The scheme method displayed is a particular process of which Resilient Modulus for stabilized subgrade can be determined directly. The results show impressive due to obtain a high value for regression for sets of models; we obtained another accurate result for Mr by using Gene expression programming. Following the model design is stablished; the powers and deficiencies of the proposed models are tested by matching the Resilient Modulus proposed from two models with the Resilient Modulus extracted from experimental test concerning the R2 values. Further, in the neural network model, an exact assessment was achieved using r2 = 0.97. Genetic algorithm with a coefficient of determination (R2) of 0.95 to determine the Resilient Modulus of stabilized subgrade. Achievement estimation of the ANN and genetic algorithm pointed out that the theses methods were capable to predict Resilient Modulus of stabilized with powerful and higher efficiency and outcomes of these models was more conventional to the experimental results. Finally, sensitivity analysis of the achieved models has been performed to examine the impact of input variables on output (Mr) and determines that the cement percentage, lime percentage, fly ash percentage, PI, clay percentage, MC, OMC, and silt percentage are the powerful variables on the Resilient Modulus of stabilized subgrade.
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estimation of subgrade soils Resilient Modulus from in situ devices test results
Journal of Testing and Evaluation, 2009Co-Authors: M R Mitchell, R E Link, Louay N Mohammad, Munir D Nazzal, Murad Abufarsakh, Khalid A AlshibliAbstract:Field and laboratory testing programs were conducted to develop Resilient Modulus prediction models for application in the design and evaluation procedures of pavement structures. The field testing program included conducting several in-situ tests such as Geogauge, Light Falling Weight Deflectometer, and Dynamic Cone Penetrometer (DCP). The laboratory program consisted of performing repeated load triaxial Resilient Modulus tests, physical properties, and compaction tests on soil samples obtained from tested sections. A total of four subgrade soil types at different moisture-dry unit weight levels were considered. Comprehensive statistical analyses were conducted on the field and laboratory test results. Two sets of models were developed. The first set (direct model) directly relates the laboratory measured Resilient Modulus values with the results of each of the three in-situ devices, whereas the second set (soil property model) incorporates soil properties in addition to the results of each of the three in-situ devices. A good agreement was observed between the predicted and measured values of the Resilient Modulus. Furthermore, the results showed that the Resilient Modulus prediction was enhanced when the soil properties were included as variables within the models. Among the models developed, the DCP-soil property model had the best prediction of Resilient Modulus followed by the DCP-direct model. The effectiveness of the DCP models were further evaluated during a forensic analysis of pavement section failure in a highway within Louisiana.
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development of models to estimate the subgrade and subbase layers Resilient Modulus from in situ devices test results for construction control
2008Co-Authors: Louay N Mohammad, Ananda Herath, Munir D Nazzal, Murad Abufarsakh, Ravindra Gudishala, Khalid A AlshibliAbstract:The objective of this study was to develop Resilient Modulus prediction models for possible application in the quality control/quality assurance (QC/QA) procedures during and after the construction of pavement layers. Field and laboratory testing programs were conducted to achieve this objective. The field testing program included conducting GeoGauge, light falling weight deflectometer, and dynamic cone penetrometer in situ tests. The laboratory program included performing repeated load triaxial Resilient Modulus tests and physical properties and compaction tests on soil tested in the field. A total of four cohesive soil types and three types of granular materials at different moisture-dry unit weight levels were considered. Comprehensive statistical analyses were conducted on the field and laboratory test results. Regression models that correlate the Resilient Modulus to the results of different in situ test devices and soil physical properties were developed. A good agreement was observed between the predicted and measured values of the Resilient Modulus. The results of this research study demonstrated a promising role of the different in situ tests considered in the QC/QA procedures of the construction of pavement layers.
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prediction of Resilient Modulus of cohesive subgrade soils from dynamic cone penetrometer test parameters
Journal of Materials in Civil Engineering, 2007Co-Authors: Louay N Mohammad, Ananda Herath, Murad Abufarsakh, Kevin Gaspard, Ravindra GudishalaAbstract:Current pavement design procedures recommend the Resilient Modulus of subgrade materials for pavement design and analysis. The objective of this paper is to develop two statistical models to predict the Resilient Modulus of subgrade cohesive soils from the dynamic cone penetration (DCP) test parameters and soil properties. The first model correlates Resilient Modulus to the dynamic cone penetration test parameters, while the second model correlates Resilient Modulus to both the dynamic cone penetration test parameters and soil properties. Field and laboratory experiments were conducted at 31 sites in Louisiana that contain four common soil types (A-4, A-6, A-7-5, and A-7-6). Field tests included DCP tests and soil sampling, while laboratory tests included determining basic soil properties and Resilient Modulus. Statistical analyses were conducted on the collected data, and two statistical models were developed for the prediction of Resilient Modulus of cohesive subgrade soils from the DCP test parameters and soil properties. The models predicted a separate data set that was not used in their development, indicating the success of the application of the dynamic cone penetration test in evaluating the Resilient Modulus of pavement subgrade soils. The predicted values obtained from the proposed models corresponded well with the measured Resilient Modulus values from the repeated load triaxial test.
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the use of dynamic cone penetrometer to predict Resilient Modulus of subgrade soils
Geo-Frontiers Congress 2005, 2005Co-Authors: Ananda Herath, Louay N Mohammad, Kevin Gaspard, Ravindra Gudishala, Murad AbufarsakhAbstract:The Resilient Modulus is used in the characterization of base and subgrade soils and in the design of pavement structures. The Resilient Modulus of subgrade soils can be estimated by using expensive and time-consuming laboratory test results or from overestimated backcalculated values from nondestructive test results. These limitations imply that the need of a simple and inexpensive insitu geotechnical test method to estimate the Resilient Modulus of subgrade soils. The dynamic cone penetration test is considered as a simple, rapid, and economical insitu test in geotechnical applications. However, the application of the dynamic cone penetration test in evaluating the Resilient Modulus of pavement subgrade soils is not well known. The objective of this paper is to develop correlations to predict the Resilient m odulus of subgrade cohesive soils from the dynamic cone penetration test parameters, soil type, moisture content, and dry unit weight. Twelve laboratory -compacted large soil samples of two cohesive soil types and six test locations in two existing pavement s were used to perform the dynamic cone penetration tests. Laboratory Resilient Modulus and soil property tests were also performed. The preliminary estimation models were developed for the prediction of the Resilient Modulus of subgrade soils from the dynamic cone penetration test parameters, moisture content, dry unit weight, and other soil properties. The models predicted separate data sets that were not used in their development, indicating the success of the application of the dynamic cone penetration test in evaluating the Resilient Modulus of pavement subgrade soils.
Shabbir M Hossain - One of the best experts on this subject based on the ideXlab platform.
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estimation of subgrade Resilient Modulus for fine grained soil from unconfined compression test
Transportation Research Record, 2015Co-Authors: Shabbir M Hossain, Wan Soo KimAbstract:The Resilient Modulus of subgrade soil is used to design a pavement structure that is adequate for the expected traffic and environmental loading. Both mechanistic and empirical design procedures use this property. The Resilient Modulus test is a complex test that requires significant resources, including a high level of technical ability on the part of the operator. For smaller or less critical projects with a low volume of traffic where costly and complex Resilient Modulus testing is not justified, a correlation with other, simpler tests could be used. In this study, a correlation with the results of an unconfined compression (UC) test is explored for estimation of the Resilient Modulus of fine-grained soils. This paper presents several models with which to estimate the Resilient Modulus of fine-grained soil from the results of UC tests considering two sample preparation techniques: static and impact compaction. The simplest model considers only unconfined compressive strength to predict the Resilient m...
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estimation of subgrade Resilient Modulus using the unconfined compression test
Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013Co-Authors: Shabbir M Hossain, Wan Soo KimAbstract:To facilitate pavement design, the new proposed mechanistic-empirical pavement design guide recommends the Resilient Modulus to characterize subgrade soil and its use for calculating pavement responses attributable to traffic and environmental loading. Although Resilient Modulus values could be determined through laboratory testing of actual subgrade soil samples, such testing would require significant resources including a high level of technical capability to conduct the test and interpret results. For smaller or less critical projects, where costly and complex Resilient Modulus testing is not justified, correlation with the results of other simpler tests could be used. The Virginia Department of Transportation (VDOT) uses a simple correlation with the California bearing ratio (CBR) to estimate the Resilient Modulus in their current pavement design procedure in accordance with the 1993 American Association of State Highway and Transportation Officials (AASHTO) design guide. As this correlation with CBR is considered to be poor, a simpler unconfined compression (UC) test was explored for better estimation of the Resilient Modulus of fine-grained soils. Several models were developed in this study to estimate the Resilient Modulus of fine-grained soil from the results of UC tests. The simplest model considers only the UC strength to predict the Resilient Modulus with a fair correlation. The more detailed models with stronger correlations also consider the plasticity index, percentage of materials passing the No. 200 sieve, and Modulus of the stress-strain curve from the UC test. These models are recommended for implementation by VDOT.
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estimation of subgrade Resilient Modulus for virginia soil
Transportation Research Record, 2009Co-Authors: Shabbir M HossainAbstract:In 2004, the Mechanistic-Empirical Pavement Design Guide (MEPDG) was developed under NCHRP Project 1-37A to replace the currently used 1993 AASHTO guide. Implementing the MEPDG requires the mechanistic characterization of pavement materials and the calibration of performance prediction models by the user agencies. The Virginia Department of Transportation required a guideline for the mechanistic characterization of subgrade soils in its MEPDG implementation. More than 100 soil samples representing every physiographic region in Virginia were collected for Resilient Modulus testing, including quick shear and soil index properties, standard Proctor values, and California bearing ratio. Resilient Modulus values and regression coefficients of constitutive models for the Resilient Modulus of typical Virginia soils were successfully computed. They could be used for the MEPDG Level 2 or Level 3 design and analysis of smaller projects for which costly and complex Resilient Modulus testing is not justified. Correla...
Mostaqur Rahman - One of the best experts on this subject based on the ideXlab platform.
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field and laboratory characterization of subgrade Resilient Modulus for pavement mechanistic empirical pavement design guide application
Transportation Research Record, 2020Co-Authors: Kazi Moinul Islam, Sarah L Gassman, Mostaqur RahmanAbstract:The Resilient Modulus (MR) of subgrade material is an important parameter in pavement design using the Mechanistic-Empirical Pavement Design Guide (MEPDG) and has a significant influence on pavemen...
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effect of Resilient Modulus of undisturbed subgrade soils on pavement rutting
International Journal of Geotechnical Engineering, 2019Co-Authors: Mostaqur Rahman, Sarah L GassmanAbstract:AbstractThis paper presents the results from a test program to characterise Resilient Modulus (M R ) of subgrade soils for different geographic regions in South Carolina. For this study, Shelby tube samples of subgrade soils were collected from existing pavements in different regions: SC-93 in Pickens county (Upstate Area), US-521 in Georgetown county (Coastal Plain), and US-321 in Orangeburg county (Coastal Plain, near the fall line). Resilient Modulus model parameters were obtained using both the bulk stress model and the generalised constitutive Resilient Modulus model. Statistical analysis was performed to develop M R estimation models for undisturbed soils using soils index properties. A correlation between laboratory measured M R with the Modulus from Falling Weight Deflectometer tests was also developed. Finally, the effects of M R on subgrade rutting were studied using MEPDG. Results showed that the developed models offer higher reliability than the universal Long-Term Pavement Performance models ...
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correlations of permanent strain and damping coefficients with Resilient Modulus for coarse grained subgrade soils
International Journal of Geotechnical Engineering, 2019Co-Authors: Mostaqur Rahman, Kazi Moinul Islam, Sarah L GassmanAbstract:ABSTRACTIn addition to the Resilient Modulus (MR), the permanent deformation and damping characteristic of subgrade soils also need to be studied to properly understand the subgrade soil behaviour ...
A S Muhanna - One of the best experts on this subject based on the ideXlab platform.
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Resilient Modulus measurement of fine grained subgrade soils
Transportation Research Record, 1999Co-Authors: A S Muhanna, M S Rahman, P C LambeAbstract:The effects of several variables that may influence the Resilient Modulus of fine-grained subgrade soils have been studied using two different soils. The number of load applications, the rest period, and the load sequence are shown to have no significant effect on the measured Resilient Modulus. It is also demonstrated that confining pressure in the range of 0 to 69 kPa (0 to 10 psi) has less than a 5 percent effect on the measured Resilient Modulus of the investigated soils. However, the condition of specimen ends is shown to influence the measured Resilient Modulus. A comparison between the measured Resilient Modulus for both soils using impact and kneading compaction methods is also presented.
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model for Resilient Modulus and permanent strain of subgrade soils
Transportation Research Record, 1998Co-Authors: A S Muhanna, M S Rahman, P C LambeAbstract:The Resilient Modulus and cumulative permanent strain of subgrade soils under anticipated repeated loading are important considerations for the design of a pavement against fatigue and rutting failures. A simple model was developed to evaluate the Resilient Modulus and accumulated permanent strain of cohesive subgrade soils under repeated loads. The empirical model was derived from the observed behavior of an A-6 cohesive soil. The model was tested against an A-5 soil. The proposed model was found to predict adequately the Resilient Modulus and the accumulated plastic strain for all A-6 and A-5 specimens with 90 percent confidence intervals of 0.61 and 1.4, and 0.66 and 1.39, respectively.
