1. PAVEMENT CONDITION SURVEYS Lecture 4

2. Instructional Objectives n Need for condition surveys n Collection methodologies n Four basic types of condition surveys n Different procedures and equipment available

3. Need for Condition Surveys n Evaluate current condition of pavement n Determine rates of deterioration n Project future conditions n Determine maintenance & rehabilitation needs n Determine costs of repairs n Prepare plans for repairs

4. Types of Surveys n Distress Surveys n Structural Capacity n Roughness (Ride Quality) n Skid Resistance (Surface Friction)

5. Distress Surveys n Type of distress n Severity n Extent of distress present on the pavement

6. Distress Surveys Types n Paser n Paver n SHRP n Asphalt Institute n Texas Transportation Institute

7. Paser n Asphalt n Concrete n Gravel Roads

8. Paser Distress-Asphalt Uses visual inspection techniques Surface defects Surface deformation Cracks Patches and potholes

9. Paser Distress-Concrete n Uses Visual inspection techniques —Surface defects —Joints —Pavement cracks —Pavement deformation

10. LTPP Distress Asphalt Concrete

11. LTPP Distress-Asphalt Cracking Patching and potholes Surface deformations Surface defects Misc distress

12. LTPP Distress-Concrete Cracking Joint deficiencies Surface defects Misc distresses

13. Paver Distress Asphalt Concrete

14. Paver Distress-Asphalt Alligator cracking Block crack Distortions Longitudinal and transverse cracking Patching and utility cuts Rutting

15. Paver Distress- Concrete Blow-ups and Buckling Corner break D cracking Linear cracking Polished aggregate Pumping

16. Ride Quality IRI (International Roughness Index) IRI is calculated from longitudinal profile measured with a road profiler in both wheelpaths. The average IRI of the two wheelpaths is reported as the roughness of the pavement section.

17. ROUGHNESS SURVEY n Survey the outside lane. n For undivided highways survey one direction. n For divided highways survey the outside lane in both directions. n For each survey cycle use the same direction(s) of travel and survey lane(s).

18. IRI CALCULATION International Roughness Index (IRI) - The IRI is computed from a single longitudinal profile using a quarter-car simulation as described in the report, "On the Calculation of IRI from Longitudinal Road Profile." [Sayers 95]

19. Ride Quality RUT DEPTH MEASUREMENT 1.7 m 3 Rutting Sensors

20. WHAT IS REPORTED?

21. SAMPLE DATA AGGREGATION 0 5 10 15 20 25 30 35 40 45 Level 1 Level 2 Level 3Level 4 Severity Level Percent of Measurements within the Section

22. Structural Capacity n Not routinely collected for pavement monitoring n Mainly used for selecting and designing rehabilitation strategies n Can reduce maintenance and rehabilitation costs

23. Structural Evaluation Destructive Testing n Coring n Laboratory testing n Excavation of pits n Field CBR

24. Structural Evaluation Non-Destructive Testing n Benkelman Beam n Dynaflect n Road Rater n FWD n Rolling Deflectometer n GPR

25. Automated Distress Surveys n Increase speed and ease of data collection n Reduce transcription errors n Increase consistency between classification and quantification n Increase safety of field crews

26. Automated Condition Survey Equipment n Used by most states to collect: –Pavement friction –Roughness –Profile –Rut depth –Deflection data

27. Classes of Automated Data Collection n Distress images collected on film or high resolution video and: –analyzed while the vehicle collects data –analyzed in the office after data collection –analyzed after data collection by viewing the images n Lasers are used to determine changes in surface texture

28. Rolling Weight Deflectometer n Primary objectives are: –Develop an RWD suitable for network level analysis –Collect data at speeds of 50 mph –Output will be a structural index –Measure maximum deflection, pavement temperature, station numbers, and day and time of test

29. Rolling Weight Deflectometer n Phase I –Identified deflection measurements n Phase II –Highway speeds –Deflection response converted to a structural index

30. Rolling Weight Deflectometer n Objective is to compare relative structural strengths n Identify weak links n Deflection basins, magnitudes, loads and temperatures n Processed in real time n Continuously measured at 1 foot intervals

31. Distress Data Collection n Visual survey n Laser technology n Film-based systems n Video systems

32. Drainage Surveys n Poor drainage causes poor pavement performance n Water on a pavement can: –create a hazard to motorists –saturate the subgrade soil –deteriorate the pavement

33. Pavement failure is caused by: n Load –Load capacity can be increased by an overlay n Moisture –If proper drainage is not provided during rehabilitation, the same moisture related distress will recur

34. Signs of Deficient Drainage n Standing water in ditchlines n Concentrated weed growth in ditchline or edge of pavement n Evidence of water ponding on shoulder n Deteriorated joint or crack sealants n Any evidence of pumping

35. How Much Data to Collect? n To support network-level analysis –Sampling processes n Two sampling procedures: –Network sampling –Section sampling

36. Network Sampling n Less samples needed when total number in the whole increases n To determine average condition: –Sample 2 - 5% n To predict the distribution of condition: –Sample 10 - 25% n To predict cost of repairs, restorations: –Sample 30 - 35% n Most states survey 10%

37. Section Sampling n To identify sections of pavement in a selected condition level, the condition of each section must be defined n If a windshield survey is used: –entire section should be inspected n If a walking or automated survey is used: –a portion of the section is adequate

38. Frequency of Surveys n Not all sections need to be inspected every year n Interstates and more important sections can be inspected every year n Sections with lower usage can be inspected every second or third year n Use of a condition project method to utilize a common period for analysis

39. Instructional Objectives n Need for condition surveys n Collection methodologies n Four basic types of condition surveys n Different procedures and equipment available