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NCHRP Synthesis 381: Falling Weight Deflectometer Usage (2008)
National Cooperative Highway Research Program Synthesis Program (NCHRPSYN)

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Alavi, Sirous, Tavares, Michael P, LeCates, Jeffrey F, Transportation Research Board. "Part 7: FWD Field Testing - Rigid Pavements." NCHRP Synthesis 381: Falling Weight Deflectometer Usage. Washington, DC: The National Academies Press, 2008.

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Page
93
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Page
93
Front Matter (R1-R10)
Summary (1-2)
Purpose (3-3)
Scope (4-4)
Definitions (5-6)
Falling Weight Deflectometer Types and Configurations (7-7)
Falling Weight Deflectometer Manufacturers (8-9)
Maintenance Practices (10-11)
Calibration Procedures (12-12)
Calibration Requirements (13-13)
Calibration Centers (14-14)
Data Collection Guidelines (15-19)
Data Storage (20-20)
Data Analysis Methods (21-21)
Data Analysis Software (22-22)
Analysis Output File Types (23-23)
Qualifications (24-24)
Additional Training Opportunities (25-26)
Outsourcing Requirements (27-28)
Case 2. Pavement Rehabilitation and Overlay (29-29)
Case 4. Pavement Management Systems (30-30)
Case 7. Spring Load Restrictions (31-31)
Case 11. Project Acceptance and Evaluation (32-32)
Case 12. Conversion of Data from Other Nondestructive Testing Devices (33-33)
Case 13. International Practices (34-34)
Portable Falling Weight Deflectometer (35-35)
Mechanistic-Empirical Pavement Design (36-36)
CHAPTER TEN - Conclusions (37-38)
References (39-42)
Bibliography (43-43)
Abbreviations (44-44)
APPENDIX A - Survey Questionnaire (45-67)
Part 1: Background Information (68-68)
Part 2: FWD Equipment Types (69-69)
Part 3: FWD Equipment Maintenance (70-73)
Part 4: FWD Equipment Calibration (74-79)
Part 5: GeneraL FWD Testing Procedures (80-83)
Part 6: FWD Field Testing - Flexible Pavements (84-92)
Part 7: FWD Field Testing - Rigid Pavements (93-102)
Part 8: FWD Computers (103-104)
Part 9: Data Analysis (105-107)
Part 10: Data Management and Storage (108-109)
Part 11: Personnel Training (110-115)
Part 12: FWD Program Administration - Part 1 of 2 (116-117)
Part 13: FWD Program Administration - Part 2 of 2 (118-126)

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OCR for page 93
93 Question 39: Under which of these conditions is flexible pavement testing not allowed? (Check all that apply.) FIGURE B34 Survey response to Question 39: "Under which of these conditions is flexible pavement testing not allowed?" (Check all that apply.) Part 7: FWD Field Testing--Rigid Pavements Question 40: What kind of rigid field testing manual does your agency use? FIGURE B35 Survey response to Question 40: "What kind of rigid field testing manual does your agency use?"

OCR for page 94
94 Question 41: How much time does a complete rigid pavement network-level FWD testing cycle take? FIGURE B36 Survey response to Question 41: "How much time does a complete rigid pavement network level FWD testing cycle take?" Question 42: For rigid pavement at the network level, are FWD tests done before the project starts, after the project is com- pleted, or both? FIGURE B37 Survey response to Question 42: "For rigid pavement at the network level, are FWD tests done before the project starts, after the project is completed, or both?"

OCR for page 95
95 Question 43: For any given rigid pavement project, approximately how soon before the project starts does your agency per- form FWD tests? FIGURE B38 Survey response to Question 43: "For any given rigid pavement project, approximately how soon before the project starts does your agency perform FWD tests?" Question 44: For any given rigid pavement project, approximately how soon after the project is completed does your agency perform FWD tests? FIGURE B39 Survey response to Question 44: "For any given rigid pavement project, approximately how soon after the project is completed does your agency perform FWD tests?"

OCR for page 96
96 Question 45: Where on rigid pavements are data collected? (Check all that apply.) FIGURE B40 Survey response to Question 45: "Where on rigid pavements are data collected?" (Check all that apply.)

OCR for page 97
97 Questions 46­49: For each of the following levels, describe your rigid pavement measurement variables, where applicable. Question 46: Project level (including forensics) FIGURE B41 Survey responses to Question 46, Project Level (Including Forensics): "For each of the following levels, describe your rigid pavement measurement variables, where applicable."

OCR for page 98
98 TABLE B12 Survey question 46: "For each of the following levels, describe your rigid pavement measurement variables, where applicable" Rigid pavement temperature gradient holes at the project level (including forensics) No. of Temperature Temperature Gradient Temperature Gradient Hole Responding State Gradient Holes Hole Depth(s) Measurement Frequency Idaho 1 Pavement mid-depth 20 min Louisiana 1 1 in. 1 min Montana 1 1 in. 1 min Wisconsin 1 Bottom of slab -- Michigan 4 1, 3, 5, and 8 in. 15 min Note: -- = no response given. TABLE B13 Survey question 46: "For each of the following levels, describe your rigid pavement measurement variables, where applicable." Other rigid pavement testing variables at the project level (including forensics) Responding State Other Testing Variables Alabama All projects more than 1 mile in length are tested every two-tenths of a mile; projects less then 1 mile are tested every tenth of a mile. Alaska No temperature gradient holes are done. Air and surface temperatures are measured. Testing is done at centerline of slab and across joints. California For temperature, we record ambient and pavement surface temperatures. Colorado We follow LTPP test sequence in center of slab. Idaho Temperature is taken at mid-depth of pavement at a minimum of one per hour. Indiana Surface temperature only. Iowa Surface temperatures are obtained with temperature sensor at test time. Kansas Varies. Maryland Varies depending on project. Michigan Time history testing. Nevada We use infrared surface temperatures for gathering temperature data. This measurement is taken at every test location. New Jersey We employ various LTPP setups and loads to 16,000 lb. North Carolina Asphalt surface temperature is taken at every drop location. Pennsylvania We do not drill any holes for taking temperatures.

OCR for page 99
99 Question 47: Network level FIGURE B42 Survey responses to Question 47, Network Level: "For each of the following levels, describe your rigid pavement measurement variables, where applicable."

OCR for page 100
100 TABLE B14 Survey question 47: "For each of the following levels, describe your rigid pavement measurement variables, where applicable" Rigid pavement temperature gradient holes at the network level No. of Temperature Temperature Gradient Temperature Gradient Hole Responding State Gradient Holes Hole Depth(s) Measurement Frequency Michigan 4 1, 3, 5, and 9 in. 15 min Montana 1 1 in. 1 min Note: -- = no response given. TABLE B15 Survey question 47: "For each of the following levels, describe your rigid pavement measurement variables, where applicable" Other rigid pavement testing variables at the network level Responding State Other Testing Variables No temperature gradient holes are done. Air and surface temps are measured. Testing is done at centerline of Alaska slab and across joints. Indiana Surface temperature only. Iowa Surface temperature obtained with temperature sensor at test time. Utah Only tests for load transfer are done at network level.

OCR for page 101
101 Question 48: Research level FIGURE B43 Survey responses to Question 48, Research: "For each of the following levels, describe your rigid pavement measurement variables, where applicable."

OCR for page 102
102 TABLE B16 Survey question 48: "For each of the following levels, describe your rigid pavement measurement variables, where applicable" Rigid pavement temperature gradient holes for research Temperature Gradient No. of Temperature Temperature Gradient Hole Measurement Responding State Gradient Holes Hole Depth(s) Frequency Idaho 1 Pavement mid-depth 20 min Illinois 1 5 in. -- Louisiana 1 1 in. 1 min Montana 1 1 in. 1 min Wisconsin 1 Slab bottom -- Note: -- = no response given. TABLE B17 Survey question 48: "For each of the following levels, describe your rigid pavement measurement variables, where applicable" Other rigid pavement testing variables for research Responding State Other Testing Variables California Recorded data for temperature is ambient and pavement surface. Colorado We test when requested and researchers let us know what they want. Florida Load transfer and corner slab analysis with a.m. and p.m. testing, center slab analysis. Idaho Temperature taken at mid-depth of pavement at a minimum of once per hour. Indiana Surface temperature only. Iowa Varies by project request. Kansas Varies by research request. Maryland Varies widely. Michigan Depending on research requests, everything can vary. Nevada We use infrared surface temperatures for gathering temperature data. This measurement is taken at every test location. New Jersey We employ various LTPP setups with loads to 16,000 lb. North Carolina Asphalt surface temperature is taken at every drop location. Virginia Number of drops, drop heights, load and location will be as per the request. Question 49: Other levels No responses were given to this question.