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Publication Number: FHWA-HRT-10-049
Date: August 2010

LTPP Specific Pavement Studies (SPS) Materials Action Plan Final Report

Chapter 4. MAP Accomplishments

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4.1 Test Results

The number of tests ordered from the laboratory contractor and the number of test results obtained are shown in table 5. The difference between tests ordered and results obtained is due to inadequacy of specimens for the requested tests. Approximately 95 percent of the MAP material tests ordered from the LTPP contract material test laboratory were able to be tested following the rigorous LTPP test protocols. It is common in pavement field and laboratory testing to obtain samples that cannot be tested in the laboratory due to a number of practical constraints, such as inadequate material, damaged cores, or too-thin layers.

Table 5. Comparison of MAP tests ordered versus delivered data results.

Test Designation

Tests Ordered

Results Obtained

AC01

2,169

2,076

AC02

1,462

1,359

AC03

401

397

AC04

434

431

AC07

426

361

AE01

45

45

AE03

387

386

AE05

390

389

AG01

414

412

AG02

410

353

AG04

389

386

AG05

548

463

PC01

51

43

PC02

79

71

PC04

98

92

PC05

95

93

PC06

424

384

PC08

167

163

SS01

57

57

SS02

146

146

SS03

147

147

SS04

9

9

SS05

1

1

SS07

260

236

SS13

431

431

TB01

780

725

UG01

66

66

UG02

66

63

UG04

64

64

UG07

189

175

UG13

258

256

Totals

10,863

10,280

Specimens for the Superpave®-related binder tests (AE07, AE08, and AE09) were planned for testing by a related national HMA pavement research program but were not tested by 2009. Test specimens for PCC thermal coefficient of expansion (PC03) were sent to FHWA's Turner‑Fairbank Highway Research Center for testing consideration. While some of these specimens may have been tested, they were not included in the official MAP tracking system since these tests were performed under voluntary participation by the test laboratories.

A comparison of the number of available and missing material test results by material type and test method between 2004 and 2009 is shown in table 6. The numbers presented in this table were generated using database queries based on general rules for material data requirements. Due to the myriad details associated with each SPS project site, the numbers do not necessarily represent missing data needed to characterize a pavement structure based on other potential data inferences. This comparison was intended to provide an "apples-to-apples" time comparison for management purposes based on a macro business rules approach that takes into account rule changes. The numbers in the 2004 columns are from the internal report LTPP SPS Materials Data Resolution, written in August 2004. The numbers in the 2009 column were generated using as similar methodology as possible based on data from LTPP Standard Data Release 24.

Table 6. Comparison of materials test data status by material layer type and test protocol from 2004 to 2009 for SPS projects included in the MAP.

Layer Type

Test

2004

2009

Available

Missing

Available

Missing

AC

AC01a

6,321

1,167

13,552

338

AC02

3,945

1,744

6,712

351

AC03

371

292

893

72

AC04

399

284

1,101

72

AC07

255

357

607

97

AE03

362

319

764

96

AE05

357

321

761

96

AG01

304

346

700

113

AG02

300

348

706

111

AG04

391

289

874

79

AG05

107

488

514

143

PCC

PC01

1,140

31

1,241

16

PC02

992

29

1,097

16

PC03

2

88

267

56

PC04

372

50

446

27

PC06

1,537

334

2,022

110

PC08

18

121

131

67

Treated Base, Treated Subbase, and Treated Subgrade

TB01

85

1,551

817

71

AC01a

590

590

1,261

321

AC02

435

652

997

334

AC03

52

110

154

42

AC04

120

47

265

14

AC07

35

118

66

104

AE03

58

109

136

38

AE05

53

109

136

38

AG01

48

110

132

41

AG02

41

116

74

93

AG04

116

50

193

15

AG05

18

137

104

64

PC01

422

48

459

29

PC02

3

90

45

40

PC03

0

93

0

56

PC04

1

92

51

35

PC06

216

511

419

372

PC08

0

93

52

33

Granular Base, Granular Subbase, and

Subgrade

UG01, UG02, SS01

766

72

1,336

137

SS02

466

244

804

90

UG04, SS03

770

300

1,324

134

UG07, SS07

384

583

809

222

Specific Gravitya

N/A

N/A

633

262

Dynamic Cone Penetrometera,b

N/A

N/A

1,661

223

a A single test may provide results for multiple layers. The numbers provided here are on a per-layer basis.
b
Test was not required prior to 2004.

The numbers in the "missing" columns represent the number of additional tests that would be required to fulfill the following criteria:

In addition, the layer must have at least 1.5 inches in representative thickness in the database for a test to be required (with the exception of thickness measurements in the AC01, PC06, and TB01 tests).

The information in table 6 does not reflect limitations on sampling due to field conditions or the suitability of specimens for the respective test. In the case of treated base materials, these test requirements were determined solely on the basis of the material description previously reported and stored in the database. In some cases, based on the new MAP field sampling, the material was found to be unsuitable for the planned tests. In other situations, the difference between the previously reported pavement structure and the findings from the MAP field investigations did not allow for corrections to be made in the field.

The change in materials data availability is summarized in table 7. Note that the number of required tests increased substantially due to additional layers discovered during the MAP sampling program and to additional required tests such as DCP and specific gravity of unbound materials. Also, the increase in available test results is substantially higher than the 10,280 tests performed by the laboratory contractor. The reasons for this difference are as follows:

Table 7. Increase in availability of material test data from 2004 to 2009 on SPS-1, -2, -5, -6, and -8 project sites.

 

April 2004

November 2009

Change

Required Tests

34,529

48,984

14,455

Available Tests

22,359

44,316

21,957

Missing Tests

12,170

4,668

-7,502

Percent Missing

35%

9%

24%

Detailed information on materials data availability by project, section, layer, and specific test designation is tabulated in the appendices.

4.2 Summary of MRL Sample Collection

Although the collection of MRL samples was strongly supported by FHWA, storage of samples in the MRL for potential future use was assigned a lower priority due to financial constraints. The effort was dependent on the highway agencies' generosity in carrying out the sampling.

It was recommended that the same number of cores be obtained for the MRL as for the new and aging tests. Although the goal was to obtain specific numbers of cores that included all asphalt concrete (AC) or PCC layers within the project, this was not always achieved. In some cases, sufficient cores were collected but some or all of them included less than the total layers in the project. Table 8 summarizes the number of project-layer combinations present in the collected core samples. Of the desired samples, 74 percent of the 12-inch core samples and 61 percent of the 4-inch core samples were delivered to the MRL.

Table 8. Status of SPS AC and PCC cores for the MRL.

Experiment

Project layers

Required

Available

12-inch

4-inch

12-inch

4-inch

SPS-1

41

123

492

115

422

SPS-2

38

228

684

144

329

SPS-5

118

708

2,832

506

1,562

SPS-6

58

174

696

131

528

SPS-8 Flex

29

87

348

81

255

SPS-8 Rigid

8

24

72

18

43

Totals

292

1,344

5,124

995

3,139

Additional material in the MRL includes 473 12-inch cores and 1,071 4-inch cores of treated base material as well as 1,488 samples of bulk material.

[1] A project layer is defined as a layer common to more than one test section on a project constructed to the same material and construction requirements. Thus, more than one test section on a project may contain the same project layer.

 

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