Relating Laboratory and Field Moduli of Texas Base Materials

1998 ◽  
Vol 1639 (1) ◽  
pp. 1-11 ◽  
Author(s):  
S. Nazarian ◽  
J. Rojas ◽  
R. Pezo ◽  
D. Yuan ◽  
I. Abdallah ◽  
...  
Keyword(s):  
Resilient Modulus ◽  
Design Method ◽  
Field Tests ◽  
Pavement Design ◽  
Falling Weight Deflectometer ◽  
Nondestructive Tests ◽  
Second Stage ◽  
Base Materials ◽  
Two Stages ◽  
Falling Weight

Resilient modulus of base is an important parameter in the AASHTO pavement design method. However, the manner to determine this parameter is not well defined. Recent efforts in combining the resilient moduli from laboratory testing with those obtained in the field using nondestructive testing devices are presented. Laboratory tests were carried out in two stages. In the first stage, virgin materials from the quarry compacted to optimum moisture content were tested. In the second stage, similar base materials were retrieved from in-service roads. Specimens were prepared and tested at the corresponding field densities and moisture contents. Nondestructive tests were performed with the Falling Weight Deflectometer and the Seismic Pavement Analyzer. Based on tests on 10 different base materials from different parts of Texas, it was concluded that it may be difficult to directly compare moduli from laboratory and field tests; however, they can be combined for effective pavement design.

scholarly journals Evaluation of Resilient Modulus of Subgrade and Base Materials in Indiana and Its Implementation in MEPDG

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Richard Ji ◽  
Nayyarzia Siddiki ◽  
Tommy Nantung ◽  
Daehyeon Kim
Keyword(s):  
Resilient Modulus ◽  
Falling Weight Deflectometer ◽  
Statistical Tool ◽  
Material Constants ◽  
Analysis And Evaluation ◽  
Subgrade Soils ◽  
Base Materials ◽  
Subgrade Soil ◽  
Different Seasons ◽  
Falling Weight

In order to implement MEPDG hierarchical inputs for unbound and subgrade soil, a database containing subgradeMR, index properties, standard proctor, and laboratoryMRfor 140 undisturbed roadbed soil samples from six different districts in Indiana was created. TheMRdata were categorized in accordance with the AASHTO soil classifications and divided into several groups. Based on each group, this study develops statistical analysis and evaluation datasets to validate these models. Stress-based regression models were evaluated using a statistical tool (analysis of variance (ANOVA)) andZ-test, and pertinent material constants (k1,k2andk3) were determined for different soil types. The reasonably good correlations of material constants along withMRwith routine soil properties were established. Furthermore, FWD tests were conducted on several Indiana highways in different seasons, and laboratory resilient modulus tests were performed on the subgrade soils that were collected from the falling weight deflectometer (FWD) test sites. A comparison was made of the resilient moduli obtained from the laboratory resilient modulus tests with those from the FWD tests. Correlations between the laboratory resilient modulus and the FWD modulus were developed and are discussed in this paper.

Comparing back-calculated and laboratory resilient moduli of bituminous paving mixtures

2004 ◽  
Vol 31 (6) ◽  
pp. 988-996 ◽  
Author(s):  
Ahmed Shalaby ◽  
Tara Liske ◽  
Amir Kavussi
Keyword(s):  
Laboratory Testing ◽  
Resilient Modulus ◽  
Field Tests ◽  
Falling Weight Deflectometer ◽  
Important Indicator ◽  
Indirect Tensile Test ◽  
Test Parameters ◽  
Back Calculation ◽  
Indirect Tensile ◽  
Falling Weight

The stiffness of bituminous mixes is an important indicator of mix performance and a required input for mechanistic pavement design. Resilient modulus is one of many stiffness indicators of mixes which can be determined using laboratory testing methods or non-destructive field tests such as falling weight deflectometer (FWD) tests through back calculation. In this paper, two Manitoba mixes known as Bituminous B (Bit B) and Bituminous C (Bit C) are analysed using laboratory testing and FWD back calculation. The experiment involved samples from eight paving sites. Each site included two side-by-side sections having a common Bit B surface course over either a Bit B or a Bit C binder course. Cored samples were tested following the guidelines of the long term pavement performance protocol P07 at 5, 25, and 40 °C. The modulus of each layer was also estimated from FWD deflection measurements. Findings include correlations between the various material and test parameters and a comparison between back calculated and laboratory stiffnesses.Key words: falling weight deflectometer, indirect tensile test, resilient modulus, asphalt concrete.

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.

EVALUATION OF PFWD AS POTENTIAL QUALITY CONTROL TOOL OF PAVEMENT LAYERS

2010 ◽  
Vol 16 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Amir Kavussi ◽  
Shahaboddin Yasrobi
Keyword(s):  
Field Tests ◽  
Field Testing ◽  
California Bearing Ratio ◽  
Falling Weight Deflectometer ◽  
Drop Mass ◽  
Quality Control Tool ◽  
Plate Size ◽  
Weight Drop ◽  
Pavement Layers ◽  
Falling Weight

Portable Falling Weight Deflectometer (PFWD) that can be considered as simple equipment is mainly used to measure elastic moduli of pavement unbound layers. This paper evaluates the potential use of PFWD to reliably measure the elastic modulus of pavement layers. To achieve this, PFWD tests were conducted on highway sections selected from different projects in Tehran. The California Bearing Ratio (CBR) laboratory tests were also conducted on samples collected during field tests. PFWD testing parameters were varied while performing the field testing. These included drop weight, drop height, plate diameter and position of additional geophones. In addition, PFWD moduli were compared with those obtained from performing FWD testing on the same site. It was found that drop mass and loading plate size affect PFWD modulus significantly. In addition, the results indicated that good correlation exist between PFWD moduli and FWD and CBR results. Santrauka Nešiojamasis krintančio svorio deflektometras PFWD (angl. portable falling weight deflectometer) yra nesudetingas prietaisas, dažniausiai naudojamas kelio dangu nesurištu sluoksniu tamprumo moduliui nustatyti. Straipsnyje apžvelgta, kaip PFWD naudojamas kelio dangu sluoksniu tamprumo moduliams matuoti. Taikant PFWD išbandyti skirtinguose projektuose Teherane (Iranas) panaudoti kelio dangu skerspjūviai. Bandiniams papildomai atlikti Kalifornijos santykinio atsparumo rodiklio CBR (angl. California bearing ratio) nustatymo eksperimentiniai tyrimai. Atliekant lauko tyrimus naudoti skirtingi PFWD bandymu parametrai: krintantis svoris, kritimo aukštis, plokštes skersmuo ir papildomai išdestyti geofonai. PFWD nustatyti tamprumo moduliai palyginti su tamprumo moduliais, išmatuotais naudojant krintančio svorio deflektometra FWD (angl. falling weight deflectometer). Nustatyta, kad PFWD matavimu rezultatams didele itaka turi kritimo mase ir apkrovimo plokštes matmenys. Gauti eksperimentiniu tyrimu rezultatai parode, kad PFWD, FWD ir CBR matavimai gerai koreliuoja tarpusavyje.

Assessment of Falling Weight Deflectometer Data for Stabilized Flexible Pavements

2000 ◽  
Vol 1709 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Alexander K. Appea ◽  
Imad L. Al-Qadi
Keyword(s):  
Resilient Modulus ◽  
Ground Truth ◽  
Monitoring And Evaluation ◽  
Structural Condition ◽  
Base Layer ◽  
Falling Weight Deflectometer ◽  
Structural Capacity ◽  
Pavement Monitoring ◽  
Aggregate Base ◽  
Falling Weight

Backcalculation of pavement moduli through the utilization of the falling weight deflectometer (FWD) is used for pavement monitoring and evaluation. The performance and structural condition of nine flexible pavement test sections built in Bedford County, Virginia, have been monitored over the past 5 years using FWD. The nine sections include three groups with aggregate base layer thicknesses of 100, 150, and 200 mm, respectively. Sections 1, 4, and 7 are control, whereas Sections 2, 5, 8 and 3, 6, 9 are stabilized with geotextiles and geogrids, respectively. The FWD testing used five double-load drops ranging from 26.5 to 58.9 kN. The deflection basins obtained from the testing have been analyzed using the ELMOD backcalculation program to find the pavement structural capacity and to detect changes in the aggregate resilient modulus. The analysis shows a reduction in the backcalculated resilient modulus of the 100-mmthick base layer. The reduction was 33 percent over 5 years for the nonstabilized section compared with the geosynthetically stabilized section. The reduction in base layer resilient modulus may have resulted from subgrade fine migration into this layer as confirmed by excavation. The study confirms the effectiveness of using woven geotextile as a separator in a pavement system built over weak subgrade. This supports the continuous rutting measurements and ground truth excavation conducted in late 1997.

Using Geogrids for Base Reinforcement as Measured by Falling Weight Deflectometer in Full-Scale Laboratory Study

1998 ◽  
Vol 1611 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Thomas C. Kinney ◽  
Danielle Stone ◽  
John Schuler
Keyword(s):  
Design Procedure ◽  
Pavement Design ◽  
Silty Sand ◽  
Crushed Rock ◽  
Falling Weight Deflectometer ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Sand And Gravel ◽  
Falling Weight

A model road was constructed in a laboratory. The road consisted of asphalt over a crushed rock base and a silty sand and gravel subbase. The silty sand and gravel were placed in a very loose state to simulate a thaw-weakened, poor-quality subbase. The water table was kept at 152 mm (6 in.) below the bottom of the asphalt. The model road was divided into three sections. A geogrid was installed at the bottom of the base course material in two of the test sections, and the third was left as a control section. A falling weight deflectometer was used to measure the dynamic response of the pavement structure. The traffic benefit ratio is defined as the expected life (equivalent single-axle loads) of one section divided by the expected life of another section. The Alaska Department of Transportation and Public Facilities asphalt pavement design procedure and the NCHRP pavement design procedure were used to compare the test sections. The results from the two procedures were very similar. By using either procedure, the life of the pavement with respect to reinforcement was on the order of 2 to 4, depending on the type of grid and the depth of base course material.

Relationship Between Backcalculated and Laboratory-Measured Resilient Moduli of Unbound Materials

2003 ◽  
Vol 1849 (1) ◽  
pp. 177-182 ◽  
Author(s):  
Gerardo W. Flintsch ◽  
Imad L. Al-Qadi ◽  
Youngjin Park ◽  
Thomas L. Brandon ◽  
Alexander Appea
Keyword(s):  
Resilient Modulus ◽  
Shift Factor ◽  
Falling Weight Deflectometer ◽  
Test Results ◽  
Structural Capacity ◽  
Bulk Stress ◽  
Stress Dependent ◽  
Falling Weight ◽  
Virginia Smart Road

The resilient moduli of an unbound granular subbase (used at the Virginia Smart Road) obtained from laboratory testing were compared with those backcalculated from in situ falling weight deflectometer deflection measurements. Testing was performed on the surface of the finished subgrade and granular subbase layer shortly after construction. The structural capacity of the constructed subgrade and the depth to a stiff layer were computed for 12 experimental sections. The in situ resilient modulus of the granular subbase layer (21-B) was then back-calculated from the deflections measured on top of that layer. The back-calculated layer moduli were clearly stress-dependent, showing an exponential behavior with the bulk stress in the center of the layer. Resilient modulus test results of laboratory-compacted specimens confirmed the stress dependence of the subbase material modulus. Three resilient modulus models were fitted to the data. Although all three models showed good coefficients of determination ( R2 > 90%), the K-θ model was selected because of its simplicity. The correlation between field-backcalculated and laboratory-measured resilient moduli was found to be strong. However, when the stress in the middle of the layer was used in the K-θ model, a shift in the resilient modulus, θ, was observed. This finding suggests that a simple shift factor could be used for the range of stress values considered.

scholarly journals Pavement Design Comparative Analysis Using Bina Marga Design Method (Pt T-01-2002-B) And Pavement Design Manual (No.04/Se/Db/2017) (Case Study: Trisakti Port - Liang Anggang)

POROS TEKNIK ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 36
Author(s):  
Utami Sylvia Lestari ◽  
Nurhafni Karina Resentia
Keyword(s):  
Resilient Modulus ◽  
Design Method ◽  
Flexible Pavement ◽  
Pavement Design ◽  
Traffic Load ◽  
Main Variable ◽  
Pavement Layers ◽  
Bearing Capacity Factor

Traffic load repetition is the main variable in flexible pavement layers design. In addition, a soil bearing capacity factor is also required for determining the thickness of the flexible pavement layer so that the pavement had been designed will be in good perfomance during the that period. The determination of thickness layers using the 2002 method (Pt T-01-2002 B) is based on the traffic load during the design period and subgrade resilient modulus value. Meanwhile the 2017 method (Pavement design manual No. 04/SE/Db/2017), layers thickness was determined based on traffic load and CBR subgrade value. Based on the calculation using both methods, the pavement layers thickness with the pavement design manual 2017 method is more thick than 2002 method. While the ESAL calculation using both methods, the 2002 method value is more larger than the pavement design manual 2017 method.

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