1、Standard Practice for Quantifying Cracks in Asphalt Pavement Surfaces AASHTO Designation: R 55-10 (2013)1American Association of State Highway and Transportation Officials 444 North Capitol Street NW, Suite 249 Washington, DC 20001 TS 5a R 55-1 AASHTO Standard Practice for Quantifying Cracks in Asph
2、alt Pavement Surfaces AASHTO Designation: R 55-10 (2013)11. SCOPE 1.1. This practice covers the procedures for quantifying cracking in asphalt pavement surfaces, both in wheelpath and non-wheelpath areas. Detailed specifications are not included for equipment or instruments used to make the measurem
3、ents. According to this standard, any process that can quantify, with the accuracy stipulated herein, and that can be adequately validated, is considered acceptable. Note 1Standardization will produce consistent pavement condition estimates for network-level pavement management. As an option, the us
4、er may define and collect other data, such as edge cracking, centerline cracks, and transverse cracks. This standard is designed for use primarily with automated data collection equipment. However, accommodations have been made for manual methods. 1.2. Either automated or manual data collection surv
5、eys as defined below are acceptable. 1.2.1. Automated Data CollectionUse a vehicle traveling at near highway speeds and collect data on the entire length of roadway (100 percent sample). 1.2.2. Manual Data CollectionObserve distresses and record data on a statistically reliable sample of the lane su
6、rveyed. The confidence level in the results for each section should exceed 85 percent. Rating continuous film or tape in an office setting is considered a manual survey. 1.3. This practice does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili
7、ty of the user to establish appropriate safety and health practices and determine the applicability of regulatory limitations related to and prior to its use. 2. TERMINOLOGY 2.1. cracka discontinuity in the pavement surface with minimum dimensions of 1-mm (1/25-in.) width and 25-mm (1-in.) length. 3
8、. SIGNIFICANCE AND USE 3.1. This practice covers the procedures for quantifying cracking in asphalt pavement surfaces both in wheelpath and non-wheelpath areas for network-level pavement management applications. The intent of this practice is to quantify and differentiate between load-associated (fa
9、tigue) and non-load-associated (environmental, reflective, etc.) pavement cracking and joints. Note 2At the time this standard was drafted, it was already identified in the Highway Performance Monitoring System Reassessment 2010+ as the collection and reporting standard for pavement cracking. Howeve
10、r, this standard was not written specifically for that use and makes no 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS 5a R 55-2 AASHTO assertion about the fitness of that or any other application be
11、yond use in network-level pavement management. 4. PROCEDURE 4.1. General GuidelinesEach agency shall designate the lane(s) and direction(s) of travel to be surveyed or rated based on sound engineering principles and management needs within the agency. The following guidelines are recommended as mini
12、mums to provide long-term uniformity: 4.1.1. Survey a 2.5-m (8-ft) strip in the outside lane as shown in Figure 1. As another option, survey the 3.6-m (12-ft) full lane width. 4.1.2. For undivided highways, survey one direction. 4.1.3. For divided highways, survey the outside lane in both directions
13、. 4.1.4. For each survey cycle, it is desirable to use the same direction(s) of travel and survey lane(s). 4.2. Cracking TypesCracks may include longitudinal cracks, transverse cracks, and interconnected cracks. The intent of this practice is to quantify and differentiate between load-associated (fa
14、tigue) and non-load-associated (environmental, reflective, etc.) pavement cracking and joints. 4.2.1. For this practice, increased cracking intensity in the wheelpath as compared with the nonwheelpath areas is assumed to quantify load-associated cracking. 4.2.2. Non-load-associated cracking is quant
15、ified by the cracking measured in the non-wheelpath areas. 4.2.3. Sealed cracks will not be quantified by manual surveys. Automated data collection equipment will not quantify any discontinuity greater than 25-mm (1-in.) width. 4.3. Cracking Estimates by Type: 4.3.1. Rating Wheelpath CracksWheelpath
16、 cracking is determined in both the inside and outside wheelpaths as shown in Figure 1. 4.3.2. Rating between Wheelpath CracksNon-wheelpath cracking is determined in the area between the wheelpaths as shown in Figure 1. 2014 by the American Association of State Highway and Transportation Officials.A
17、ll rights reserved. Duplication is a violation of applicable law.TS 5a R 55-3 AASHTO Figure 1Cross Section of Survey Lane Showing Wheelpaths and Defined Survey Area Between Wheelpaths 4.3.3. Determining any additional non-wheelpath cracking for the remainder of the lane width is optional and will be
18、 defined by the agency. 4.3.4. Classify cracking by severity and intensity as indicated below: 4.3.4.1. Severity Level 1Cracks 3 mm (1/8in.). 4.3.4.2. Severity Level 2Cracks with dimensions 3-mm (1/8-in.) and 6-mm (1/4-in.) width. 4.3.4.3. Severity Level 3Cracks with dimensions 6-mm (1/4-in.) width.
19、 4.3.5. Quantify intensity of cracking at each level as the total length of cracking per unit area (m/m2or ft/ft2) for each defined survey strip as shown in Figure 1. Note 3The sample area is a function of the sample length the agency has chosen in Section 5. 5. RECORDING OF DATA 5.1. Automated Data
20、 CollectionThe entire length of the pavement shall be surveyed (100 percent sample). The data summary interval shall be 0.1 km (0.062 miles). 5.2. Manual Data CollectionThe number of samples for a given homogeneous section of pavement is determined by the desired confidence level and the variance in
21、 the samples. The minimum 85 percent confidence interval of the mean should be no greater than 10 percent of its value. Each section shall have at least four samples. For the purpose of establishing the confidence level, the total crack length for all severity levels within a survey strip may be add
22、ed together. Table 1 shows the confidence interval for example sample counts and confidence levels as a function of the standard deviation of the samples. It is understood that the samples should be distributed throughout the section. Usual Lane Width 3.6 mPavement SurfaceSurvey LaneAdjacent LaneSho
23、ulder ofAdjacent LaneLane LineLane Line*Varies*VariesSurvey Strip2.500 mInsideWPOutsideWPAreabetweenWPs*Optional0.125 0.1250.75 0.75 0.750.125 m = 0.41 ft0.75 m = 2.5 ft3.6 m = 12 ft 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a
24、violation of applicable law.TS 5a R 55-4 AASHTO Table 1Confidence Interval for Sample Counts Confidence Interval Number of Samples 85% Confidence 95% Confidence 5 1.034s 1.802s 10 0.691s 1.204s 20 0.476s 0.829s Note: Where s is the standard deviation of the samples 5.2.1. Data Collection SectionThis
25、 section should be a relatively homogeneous section of pavement based on visible construction and general condition. Section length may be determined from historical data sources or by delineators inserted during data collection. The more homogeneous the section, the fewer samples required to achiev
26、e the required confidence. 5.2.2. Data Collection SampleThe exact length of each data collection sample is determined by the agency and shall be between 0.03 km (0.02 miles) and 1.0 km (0.62 miles). Larger samples tend to have less variation. Note 4Agencies should experiment with sample size, number
27、, and section definition to minimize the data collection effort necessary to achieve the required confidence. 6. REPORT 6.1. An example of a report is given in Table 2. Table 2Example of Data Reporting Severity Level Outside Wheelpath, m/m2Inside Wheelpath, m/m2Between Wheelpaths, m/m2Optional Areas
28、 and Distress Edge Cracking Joints Transverse Cracking 1 12 19 5 User defined User defined User defined 2 25 10 2 User defined User defined User defined 3 10 12 4 User defined User defined User defined 6.2. At a minimum, report the following data: Note 5For reporting requirements, “sample” in the ma
29、nual data collection mode is equivalent to “interval” for the automated data collection mode. 6.2.1. Section IdentificationFor each data collection section, the agency shall list all information necessary to locate the section using their current referencing system; 6.2.2. Length of the data collect
30、ion section, km (miles); 6.2.3. Sample length if not 100 percent, m (ft); 6.2.4. Sample LocationThe beginning location of the sample; 6.2.5. Length within the sample for each severity level of wheelpath cracking, m (ft); 6.2.6. Length within the sample for each severity level of non-wheelpath cracki
31、ng, m (ft); and 6.2.7. The date of collection, month/day/year. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS 5a R 55-5 AASHTO 7. KEYWORDS 7.1. Asphalt pavement; between wheelpaths; crack; edge crack
32、ing; inside wheelpath; outside wheelpath; pavement management; survey strip; transverse crack. 8. REFERENCES 8.1. FHWA, Highway Performance Monitoring System Reassessment 2010+, available at http:/www.fhwa.dot.gov/policy/ohpi/hpms/2010/ch2.cfm. 8.2. SHRP. Distress Identification Manual for the Long-
33、Term Pavement Performance Project. Strategic Highway Research Program, SHRP-P-338, Washington, DC, 1993. APPENDIX (Nonmandatory Information) X1. QUALITY ASSURANCE X1.1. Quality Assurance PlanEach agency shall develop an adequate quality assurance plan. Quality assurance includes survey personnel cer
34、tification training, accuracy of equipment, daily quality control procedures, and periodic and ongoing control activities. The following guidelines are suggested for developing such a plan. X1.2. Qualification and TrainingAgencies are individually responsible for training and qualifying their survey
35、 personnel and/or qualifying contractors for proficiency in pavement rating or in operating equipment that must be used as a part of quality assurance. X1.3. EquipmentThe basic output of any equipment used shall be checked or calibrated according to the equipment manufacturers recommendations. The e
36、quipment must operate within the manufacturers specifications. A regular maintenance and testing program must be established for the equipment in accordance with the manufacturers recommendations. X1.4. Validation SectionsSections shall be located with established cracking types and levels. These se
37、ctions shall be surveyed on a monthly basis during data collection season. Comparison of these surveys can provide information about the accuracy of results and give insight into which raters or operators need additional training. Validation sections shall be rotated or replaced on a regular basis i
38、n order to ensure that raters or operators are not repeating known numbers from prior surveys. As an alternate to this procedure, up to 5 percent of the data may be audited and compared as a basis for a quality check. X1.5. Additional ChecksAdditional checks can be made by comparing the previous yea
39、rs survey summaries with current surveys. At locations where large changes occur, the data shall be further evaluated for reasonableness and consistency of trends. 1Formerly AASHTO Provisional Standard PP 44. First published as a full standard in 2010. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
