National Academies Press: OpenBook

A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers (2018)

Chapter: APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY

« Previous: APPENDIX G. CATALOG OF AGING PROPERTIES OF ASPHALT MIXTURES
Page 169
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 169
Page 170
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 170
Page 171
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 171
Page 172
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 172
Page 173
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 173
Page 174
Suggested Citation:"APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY ." National Academies of Sciences, Engineering, and Medicine. 2018. A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers. Washington, DC: The National Academies Press. doi: 10.17226/25304.
×
Page 174

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

H-1 APPENDIX H. CHARACTERIZATION OF THE TOP-DOWN CRACKING AMOUNT AND SEVERITY The objective of this appendix is to provide details regarding the calibration of the top- down cracking amount and severity with observed crack data in the field. The calibration is a process of using the mathematical techniques to minimize the error between observed and predicted values of the distress. The observed data is the historical longitudinal cracking length in the wheelpath which follows an S-shaped curve and is characterized using Equation H-1:   00 t tl t l e        (H-1) where  l t is the longitudinal cracking length; 0l is the maximum crack length (i.e., 300 m); 0t is the crack initiation time (days);  and  are scale parameter and shape parameter, respectively. Specifically, the scale factor  is the number of days needed for the longitudinal crack to reach 36.8 % of the maximum crack length. Equations and graphs for the crack initiation time are found in Chapter 5 of this report (Equations 4.53 and 4.54 and Figures 4.53 and 4.54). The shape factor  is used to determine the longitudinal crack growth rate to reach the critical crack length. For each pavement section, there is an associated set of  and  . Figures H-1 to H-4 present the plots of Equation H-1 corresponding to the measured data for the LTPP sections. (a) 0 50 100 150 200 250 300 0 3000 6000 9000 12000 15000 18000 Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day)

H-2 (b) Figure H-1. Measured Longitudinal Crack with Fitted Model for LTPP Sections 19-0110 and 9-1803 in WF Climate Zone (a) (b) Figure H-2. Measured Longitudinal Crack with Fitted Model for LTPP Sections 1-B340(a) and 12-0108(b) in WNF Climate Zone 0 20 40 60 80 0 1000 2000 3000 4000 Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day) 0 50 100 150 200 250 0 1000 2000 3000 4000 5000L on gi tu di na l C ra ck  L en gt h  (m ) Service Time (day) 0 50 100 150 0 1000 2000 3000 4000 5000 6000Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day)

H-3 (a) (b) Figure H-3. Measured Longitudinal Crack with Fitted Model for LTPP Sections 4-0115 (a) and 48-1093(b) in DNF Climate Zone (a) 0 30 60 90 120 150 0 1000 2000 3000 4000 5000L on gi tu di na l C ra ck  L en gt h  (m ) Service Time (day) 0 20 40 60 80 100 120 0 2000 4000 6000 8000 10000 12000Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day) 0 20 40 60 80 100 0 2000 4000 6000 8000 10000 12000 Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day)

H-4 (b) Figure H-4. Measured Longitudinal Crack with Fitted Model for LTPP Sections 16-1005 and 8-6013 in DF Climate Zone It is observed from the LTPP data that most of the longitudinal cracking in the wheelpath is in the low severity level. Based on the LTPP definition of low, medium and high longitudinal cracking severity levels and the empirical relationship between crack width and crack depth for the low severity crack that was developed previously (see details in Appendix J), 15 mm is selected as the critical crack depth, which corresponds to the boundary crack depth between low and medium severity levels. The crack depth when the crack makes its first appearance on the surface at the initiation time, 0t , is 7.5 mm. Table H-1 lists the calculated number of days to reach the critical crack depth and the associated  and  for the each of the pavement sections used in this analysis, which are calculated using fracture mechanics approach by the developed computer program. Table H-1. Some of Distress Parameters of LTPP Pavement Sections LTPP Pavement ID States Climate Zone Calculated Number of Days   8-7780 CO DF 2190 6938.47 0.964019 16-9034 ID DF 91 3049.322 0.482765 19-0102 IA WF 727 3399.31 0.746427 23-1009 ME WF 37 2141.21 1.84260 27-1008 MN WF 736 2885.617 1.39832 19-0101 IA WF 1095 4568.925 1.661188 0 50 100 150 200 250 300 0 5000 10000 15000 20000 25000 30000 35000 Lo ng itu di na l C ra ck  L en gt h  (m ) Service Time (day)

H-5 39-0159 OH WF 39 1770.312 1.2499 36-0801 NY WF 1511 4850.24 1.27087 9-1803 CT WF 438 1500.736 1.45564 55-B902 WI WF 361 1694.92 1.21452 19-0110 IA WF 1467 5563.06 1.4522 19-0106 IA WF 1820 3805.408 1.118528 19-0108 IA WF 1092 4586 1.237197 1-4129 AL WNF 256 1347.229 0.791057 1-1001 AL WNF 2920 8092.581 1.303464 1-6012 AL WNF 329 1752.791 1.201762 5-2042 AR WNF 366 1500 1.1 12-3996 FL WNF 292 1110.894 0.7 12-4106 FL WNF 2008 4025.214 1.099951 37-1814 NC WNF 1460 4606.184 1.278387 37-1645 NC WNF 367 1762.377 1.582345 47-9024 TN WNF 1898 4876.702875 0.963165876 48-1093 TX WNF 2555 7535.517 1.257434 48-1130 TX WNF 1825 6322.813 1.43707 48-3865 TX WNF 37 3209.91 0.87717 48-1178 TX WNF 329 3277.75 1.145596 48-3739 TX WNF 73 1772.165 1.114496 48-3669 TX WNF 73 2786.445 0.504739 48-0117 TX WNF 440 2335.064 1.321869 48-1087 TX WNF 1643 3758.935 1.153865 48-0167 TX WNF 328.5 3323.663 0.591301 1-0101 AL WNF 219 1299.16 0.95528 12-0107 FL WNF 730 3810.496 0.852988 2-1002 AK WF 365 1129 0.9 2-1004 AK DF 1533 3424.713 1.355363 30-0122 MT DF 183 749.7743 1.601905 30-0116 MT DF 219 3001.897 1.02 16-1010 ID DF 730 2072.351 1.722365 53-7322 WA DF 3285 5775.514 1.139747 30-0505 MT DF 4380 8787.46 1.200508 30-0805 MT DF 1095 4297.761 1.025329 32-0101 NV DF 2920 9790.578 1.338457 8-0509 CO DF 2555 7168.122 1.386846 8-1053 CO DF 730 5835.111 1.364831 49-1001 UT DF 730 2370.995 1.298702 56-A330 WY DF 185 3408.673 0.977611 8-6013 CO DF 840 3666.013 0.906974 56-1007 WY DF 3285 11043.75 0.83422 4-1065 AZ DNF 1497 3230.063 1.51705 4-0122 AZ DNF 110 1000.707 0.94685 4-0505 AZ DNF 2555 7896.609 1.711127

H-6 6-1253 CA DNF 2711 6931.024 1.050461 6-0502 CA DNF 1095 3102.621 1.3 35-0101 NM DNF 730 4563.722638 0.765009 35-0102 NM DNF 185 2162.86 0.712634 4-1016 AZ DNF 402 1226.936 1.184429 35-0112 NM DNF 329 3342.426 0.945329 4-0113 AZ DNF 109 2258.707 1.01565 4-0115 AZ DNF 803 2341.309 1.040928 4-0117 AZ DNF 1095 2614.476 1.234299 4-1034 AZ DNF 2555 6425.812 1.097589 35-0105 NM DNF 365 3758.456 0.860986 35-0107 NM DNF 418 4424.569 0.907809 The Paris’ law and the ANN models for different traffic levels developed previously are utilized to predict the number of days to reach the critical crack depth for each specific pavement section with the load spectra submodel. This is achieved with the computer program developed in the C# language. Once the material properties of the asphalt, base and subgrade layers, pavement structure, and load spectra are known, the number of days are calculated using this program automatically.

Next: APPENDIX I. PREDICTION OF TOP-DOWN CRACK INITIATION TIME AND DETERMINATION OF CALIBRATION COEFFICIENTS FOR DIFFERENT CLIMATE ZONES »
A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 257: A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers develops a calibrated mechanistic-empirical (ME) model for predicting the load-related top-down cracking in the asphalt layer of flexible pavements. Recent studies have determined that some load-related fatigue cracks in asphalt pavement layers can be initiated at the pavement surface and propagate downward through the asphalt layer. However, this form of distress cannot entirely be explained by fatigue mechanisms used to explain cracking that initiates at the bottom of the pavement. This research explores top-down cracking to develop a calibrated, validated mechanistic-empirical model for incorporation into pavement design procedures.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!