Gradation and Moisture Effects on Resilient Moduli of Aggregate Bases

1998 ◽  
Vol 1619 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Ping Tian ◽  
Musharraf M. Zaman ◽  
Joakim G. Laguros
Keyword(s):  
Resilient Modulus ◽  
Department Of Transportation ◽  
Linear Regression Models ◽  
Traffic Loading ◽  
Pavement Materials ◽  
Deformation Response ◽  
Moisture Contents ◽  
Base Materials ◽  
Moisture Effects ◽  
Oklahoma Department Of Transportation

Resilient modulus ( M R) which properly characterizes the load-deformation response of pavement materials under traffic loading, is evaluated. The M R values due to three different gradations and three different moisture contents were investigated for the Richard Spur and the Sawyer aggregates, which are commonly used in Oklahoma as the subbase or base materials of roadway pavements. The three gradations were finer limit, median, and coarser limit, as specified by the Oklahoma Department of Transportation for Type A aggregate. The three moisture contents selected are optimum moisture content (OMC), 2 percent below OMC, and 2 percent above OMC. To investigate the variability of the test results, six duplicate M R tests under identical conditions were performed for each case by using the AASHTO T294-94 method. Furthermore, the material properties, K1 and K2, which are required input in the AASHTO pavement design equation, were evaluated for the M R values obtained. Finally, multiple linear regression models for predicting the M R values of the two aggregates were established.

Evaluation of Resilient Modulus of Cemented Lime Rock Base Materials in Florida

1996 ◽  
Vol 1546 (1) ◽  
pp. 1-12
Author(s):  
W. Virgil Ping ◽  
Ling Ge
Keyword(s):  
Resilient Modulus ◽  
Load Test ◽  
Base Layer ◽  
Pavement Materials ◽  
Analysis And Design ◽  
Field Plate ◽  
Base Materials ◽  
Bearing Load ◽  
Load Tests ◽  
Applied Stresses

The resilient modulus of pavement materials is an important parameter in pavement analysis and design. In recent years the emphasis of research has primarily been concentrated on investigating the resilient modulus of subgrade materials. Information is lacking on the resilient modulus of base materials for determining the properties of pavement layers. The results of field plate bearing load tests and laboratory resilient modulus tests on lime rock base materials are presented. Correlation relationships between the field layer modulus and the laboratory resilient modulus are evaluated. Comparison of the computed resilient modulus of the base layer with the layer modulus from the plate bearing load test under identical moisture and density conditions indicated a trend of increasing laboratory resilient modulus with increasing plate load modulus. The average values of the layer modulus backcalculated from the plate bearing load tests were higher than those of the computed equivalent resilient modulus from the laboratory tests with the averaged applied stresses in the elastic range.

Testing Methodology for Resilient Modulus of Base Materials

1996 ◽  
Vol 1547 (1) ◽  
pp. 46-52 ◽  
Author(s):  
S. Nazarian ◽  
R. Pezo ◽  
S. Melarkode ◽  
M. Picornell
Keyword(s):  
Resilient Modulus ◽  
Design Method ◽  
Testing Procedure ◽  
State Agencies ◽  
Technical Literature ◽  
Subgrade Soils ◽  
Base Materials ◽  
Texas Department ◽  
Confining Pressures ◽  
End Restraint

Resilient moduli of base and subgrade materials are important parameters in the new pavement design method adopted by AASHTO and many state agencies. Several testing protocols for determining the resilient moduli of subgrade soils have been proposed and evaluated in the technical literature. Unfortunately, less effort has been focused on developing protocols appropriate for base materials. The main objective was to describe a resilient modulus testing procedure that has been developed for the Texas Department of Transportation. The proposed procedure contains the main steps of the AASHTO T294-92 procedure, with several exceptions. Namely, the loading sequence of the T294-92 procedure was modified to avoid subjecting the specimens to high devi-atoric stresses at low confining pressures. The conditioning cycles were replaced by a procedure in which the specimen was grouted to the platens to minimize disturbance to the specimen during stage testing. The effects of end restraint on the vertical strains were minimized by measuring the deformations of the middle one-third of the specimen. To avoid well-known problems with mounting linear variable differential transformers on the specimen, noncontact probes were used to measure deformations. To maximize the amount of information gained, the lateral deformations were also measured with noncontact probes to determine the Poisson's ratio. On the basis of tests on nine synthetic specimens with known properties and nine different base materials from different parts of Texas, it was concluded that the proposed methodology yields accurate and repeatable results.

Poisson Regression Analysis of Highway Fatality Accident Data in Oklahoma

2014 ◽  
Vol 5 (4) ◽  
pp. 72-86
Author(s):  
Jonathan C. Comer ◽  
Nicholas J. Rose ◽  
Leonard S. Bombom
Keyword(s):  
Regression Analysis ◽  
Rural Areas ◽  
Poisson Regression ◽  
Department Of Transportation ◽  
Highway Design ◽  
Crash Data ◽  
Poisson Regression Analysis ◽  
Accident Data ◽  
Oklahoma Department Of Transportation ◽  
Construction Practice

Analysis of fatality automobile accident data can be challenging in rural areas where a relatively small number of such accidents occurs on specific sections of highways. Combining crash data from the Fatality Analysis Reporting System (FARS) and highway networks and design specifications from the Oklahoma Department of Transportation (ODOT), this article employs Poisson regression analysis to determine what roadway characteristics (e.g. grade, geometry, and design) are most associated with fatal accidents on predominantly rural segments of highways in Oklahoma. The results provide information about what combinations of highway design traits have contributed most to past crashes and therefore can identify potentially dangerous road segments system-wide. This information will help transportation engineers evaluate current construction practice and seek ways to address design issues that are shown to contribute significantly to serious crashes.

Strength and Behavior of Materials for Low-Volume Roads as Affected by Moisture and Density

2003 ◽  
Vol 1819 (1) ◽  
pp. 104-109 ◽  
Author(s):  
P. Paige-Green
Keyword(s):  
Quality Assurance ◽  
Southern Africa ◽  
Laboratory Testing ◽  
Simple Technique ◽  
Material Strength ◽  
Pavement Materials ◽  
Moisture Contents ◽  
Low Volume Roads ◽  
Low Volume ◽  
And Behavior

The relationships among strength, moisture, and density in pavement subgrades and layerworks are well known, but they have particular significance in low-volume roads. In these roads, the specified density is frequently not achieved (quality assurance testing tends to be reduced), and moisture fluctuations are more severe with greater consequences. Traditional studies of the material strength for these roads in southern Africa are based almost entirely on the California bearing ratio (CBR), a test with inherent problems. The test is routinely carried out to identify whether the materials under consideration have the required soaked strengths (typically CBRs of 80% or 45% for bases of different standards) at the design compaction density. Studies of the CBR at different moisture contents and densities should be carried out to identify the implications of variations in these properties on the behavior of pavement materials. A simple technique to be carried out during conventional laboratory testing was developed. Aspects pertaining to this type of study were evaluated, and the findings were related to low-volume road behavior.

Research on the Mechanical Properties of Cement Recycled Reclaimed Asphalt Pavement Mixture

2012 ◽  
Vol 549 ◽  
pp. 715-719
Author(s):  
Shao Wen Du ◽  
Chao Fei Liu
Keyword(s):  
Fatigue Life ◽  
Asphalt Pavement ◽  
Reclaimed Asphalt Pavement ◽  
Test Results ◽  
Reclaimed Asphalt ◽  
Pavement Materials ◽  
Base Materials ◽  
Negative Effect ◽  
Strength And Durability ◽  
Cement Stabilized Base

In this paper, cement is used to stabilize reclaimed asphalt pavement materials (RAP) and original aggregate with the same gradation. Compressive strength, freezing-thawing resistance and fatigue life of cement recycled RAP mixture (CRAPM) and cement stabilize original aggregate mixture (CSAM) are evaluated. Test results indicate the compressive adhesive strength of cement-RAP is lower than cement-original aggregate. At the same gradation, RAP has negative effect on the freezing-thawing resistance of CRAPM, and can increase the fatigue life sensitive to stress level. Therefore, for using 100% RAP, it is necessary to increase the cement content to properly improve the strength and durability of RAPM in order to satisfy the specification of cement stabilized base materials in china.

scholarly journals Forma e tamanho de grãos de soja para diversos teores de água

2018 ◽  
Vol 39 (6) ◽  
pp. 2821
Author(s):  
Wilker Alves Morais ◽  
Osvaldo Resende ◽  
Fernando Nobre Cunha ◽  
Vitor Marques Vidal ◽  
Nelmício Furtado da Silva ◽  
...  
Keyword(s):  
Moisture Content ◽  
Physical Properties ◽  
Surface Area ◽  
Initial Moisture Content ◽  
Correlation Coefficients ◽  
Volumetric Shrinkage ◽  
Linear Regression Models ◽  
Moisture Contents ◽  
Soybean Cultivars ◽  
Grain Moisture

Physical properties of soybean grains present differences as a function of cultivars and moisture content, with the correlation between physical properties. This study aimed to determine the characteristics related to the physical properties of grains with different moisture contents of three soybean cultivars. The experimental design was completely randomized design in a 3 × 6 factorial scheme with three replications, consisting of three soybean cultivars (6266 RSF IPRO, BMX Potência RR, and 14403Z6001) and six grain moisture contents (11, 13, 15, 17, 19, and 21% wb). Soybean grains presented an initial moisture content of 11.0, 11.0, and 10.8% wb, respectively for 6266 RSF IPRO, BMX Potência RR, and 14403Z6001. The other moisture contents were obtained by soaking in a BOD chamber maintained at 25 °C and 93% of relative humidity. We assessed volume, roundness, sphericity, surface area, volumetric shrinkage, and volumetric shrinkage rate. The data were submitted to the analysis of variance by the F-test (p < 0.05) and when significant, regression analysis was performed for grain moisture contents and the means of cultivars were compared by the Tukey’s test. Pearson’s correlation analysis was also carried out to represent the linearity between grain physical properties. The cultivar BMX Potência RR obtained the highest results for volume, roundness, sphericity, and surface area. Volume and surface area increased as the moisture content of soybean grains increased; the opposite was observed for roundness and sphericity. A linear increase in volumetric shrinkage was observed as moisture content increased. The values of the correlation coefficients of the linear regression models can be used to describe the relationships between physical properties.

Development of New Network Optimization Model for Oklahoma Department of Transportation

1996 ◽  
Vol 1524 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Xin Chen ◽  
Stuart Hudson ◽  
Masoud Pajoh ◽  
William Dickinson
Keyword(s):  
Network Optimization ◽  
Optimization Model ◽  
Pavement Management ◽  
Road User ◽  
Department Of Transportation ◽  
Pavement Management System ◽  
Pavement Maintenance ◽  
Markov Decision ◽  
Oklahoma Department Of Transportation ◽  
New Formulation

A new pavement network optimization model based on the Markov decision process (MDP) is presented. The new model is a global optimization model in which the entire network can be optimized without being divided into mutually independent groups. Current MDP models in use for pavement management use only one routine maintenance model for all types of rehabilitation and reconstruction treatments. The new formulation provides separate routine maintenance models for each type of treatment, which is more realistic than the currently available formulations. Methods for estimating pavement maintenance and rehabilitation benefits are described. These methods can be used for the optimization models with objectives of maximization when inadequate data are available to consider road user costs. The model has been applied to the network-level pavement management system for the Oklahoma Department of Transportation. Results of example runs are discussed.

Modeling Stress- and Moisture-Induced Variations in Pavement Layer Moduli

2003 ◽  
Vol 1860 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Cheryl Richter ◽  
Charles W. Schwartz
Keyword(s):  
Moisture Content ◽  
Constitutive Model ◽  
Resilient Modulus ◽  
Monitoring Program ◽  
Elastic Theory ◽  
Pavement Materials ◽  
Seasonal Basis ◽  
Stress States ◽  
Stress Dependent ◽  
Moisture Conditions

The in situ moduli of unbound pavement materials vary on a seasonal basis as a function of temperature and moisture conditions. The development of empirical models to predict backcalculated pavement layer moduli as a function of moisture content and stress state is addressed. The work is based on data collected via the Seasonal Monitoring Program of the Long-Term Pavement Performance Program. This research identified fundamental incompatibilities between the stress states computed from layer moduli backcalculated using linear layered-elastic theory and those used in laboratory resilient modulus testing. Important implications of this finding are that (a) application of laboratory-derived constitutive model coefficients in combination with stress states computed using linear layered-elastic theory may yield inaccurate stress-dependent modulus values and (b) meaningful advances in the state of the art for backcalculation of pavement layer moduli cannot be achieved without addressing the inaccuracies and limitations inherent in the use of linear layered-elastic theory to model nonlinear pavement response. Other important findings include the following: (c) variation in moisture content is not always the most important factor causing seasonal variations in pavement layer moduli and (d) a constitutive model form suitable for approximately incorporating the stress and moisture sensitivity of layer moduli backcalculated using linear layered-elastic procedures for practical design purposes is identified.

Poisson Regression Analysis of Highway Fatality Accident Data in Oklahoma

2018 ◽  
pp. 429-444
Author(s):  
Jonathan C. Comer ◽  
Nicholas J. Rose ◽  
Leonard S. Bombom
Keyword(s):  
Regression Analysis ◽  
Rural Areas ◽  
Poisson Regression ◽  
Department Of Transportation ◽  
Highway Design ◽  
Crash Data ◽  
Poisson Regression Analysis ◽  
Highway Networks ◽  
Accident Data ◽  
Oklahoma Department Of Transportation

Analysis of fatality automobile accident data can be challenging in rural areas where a relatively small number of such accidents occurs on specific sections of highways. Combining crash data from the Fatality Analysis Reporting System (FARS) and highway networks and design specifications from the Oklahoma Department of Transportation (ODOT), this article employs Poisson regression analysis to determine what roadway characteristics (e.g. grade, geometry, and design) are most associated with fatal accidents on predominantly rural segments of highways in Oklahoma. The results provide information about what combinations of highway design traits have contributed most to past crashes and therefore can identify potentially dangerous road segments system-wide. This information will help transportation engineers evaluate current construction practice and seek ways to address design issues that are shown to contribute significantly to serious crashes.

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