An Asphalt Paving Tool For Adverse Conditions

166 Pages·2007·5.99 MB·English

iMi NTO T FR ANSPORTATI 1998-18
Repr
3 0314 00023 8922
L
L·
)·
CTS
An Asphalt Paving Tool
TE
270
.A86
For Adverse Conditions
1998
In no event will the Minnesota Department of Transportation, the University of Minnesota, or their suppliers be liable
to you or any other person for any damages, expenses, lost profits, lost savings, or other damages arising out of use
or inability to use this program.
Technical Report Documentation Page
1. Report No. 2. 3. Recipient's Accession No.
MN/RC - 1998-18
4. Title and Subtitle 5. Report Date
AN ASPHALT PAVING TOOL FOR ADVERSE June 1998
CONDITIONS
6.
7. Author(s) 8. Performing Organization Report No.
Bruce A. Chadbourn Rachel A. DeSombre
David E. Newcomb James A. Luoma
Vaughan R. Voller David H. Timm
9. Performing Organization Name and Address 10. Project/Task/Work Unit No.
University of Minnesota
DDeeppaarrttmmeenntt ooff CCiivviill EEnnggiinneeeerriinngg 11. Contract (C)o r Grant (G) No.
500 Pillsbury Drive, S.E.
Minneapolis, Minnesota 55455-0116 (C) 72632 TOC # 165
12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered
Minnesota Department of Transportation Final Report - 1995 to 1998
395 John Ireland Boulevard Mail Stop 330 14. Sponsori
14. Sponsoring Agency Code
St. Paul, Minnesota 55155
15. Supplementary Notes
16. Abstract (Limit: 200 words)
Poor compaction can lead to early deterioration of an asphalt pavement. It often happens when paving occurs
during adverse weather conditions. Yet, in Minnesota, paving must often occur under adverse conditions.
A new tool now simulates the cooling of an asphalt mat behind the paver under a variety of environmental
conditions. The software, PaveCool Version 2.0, offers users insights into how adverse climate conditions will
affect their ability to produce a durable, quality road surface. Users input the type of existing surface, type of
asphalt mix, and weather conditions. The output shows a cooling curve with recommended compaction starting and
stopping times. Field tests confirm the value of this program as an aid to cold weather paving. A Windows
program, PaveCool 2.0 runs on laptop computers (Windows 95, 98, or NT required).
This report documents the study of thermal properties and compactibility of hot-mix asphalt, related laboratory
tests on the thermal diffusivity and thermal conductivity of hot-mix asphalt at typical compaction temperatures, a
literature review, and testing results. It also includes a copy of the PaveCool Version 2.0 software.
17. Document Analysis/Descriptors 18. Availability Statement
asphalt paving cold weather construction No restrictions. Document available from:
bituminous paving asphalt compaction National Technical Information Services,
Springfield, Virginia 22161
19. Security Class (this report) 20. Security Class (this page) 21. No. of Pages 22. Price
Unclassified Unclassified 145

AN ASPHALT PAVING TOOL
FOR ADVERSE CONDITIONS
Final Report
Prepared by:
Bruce A. Chadbourn
David E. Newcomb
Vaughan R. Voller
Rachel A. De Sombre
James A. Luoma
David H. Timm
University of Minnesota
Department of Civil Engineering
500 Pillsbury Dr. SE
Minneapolis, MN 55455-0116
June 1998
Prepared for
Minnesota Department of Transportation
This report represents the results of research conducted by the authors and does not necessarily represent the views
or policy of the Minnesota Department of Transportation.

TABLE OF CONTENTS
CHAPTER 1 INTRODUCTION ................................................................................ 1
B ackground ........................................ ........ . ...................................1.
O bjectives........................................... ....... ............................ .................... 2...
Scope..................... ......................... ...... .................. . .. ...............................2
CHAPTER 2 LITERATURE REVIEW...................................................... ....................... .5
Compaction of Hot-Mix Asphalt Pavement.................... .... ........... 5
M echanics of Compaction.............................................................................. 5
Compaction of Asphalt Mixtures............................................................. 6
.W orkability of Ho t-M ix Asphalt ........................................... .................... 8
Aggregate Effects..................... ...... ......... ...... ................ ..................... 8
The Effect of Binder Viscosity ....................................... 8.
Temperature Effects ......................................... 9
Filler Effects ............................. ............................ 10
Control of Hot-Mix Asphalt Compactibility.................... ................. 10
Density and Thickness Changes During Compaction.................................. 12
Thermal Properties of Pavement Materials............................................. ........ 13
C onduction ....... ....... ..... ............................ ................ .................... 13
Convection.................... ... ...................................................... 16
Ra diation ........................................................ .. ...... ............................... 16
Laboratory Mixture Design and Compaction Methods ....................................... 18
Mixture Design Methods................................................................... 18
Methods Used to Define Workability and Compactibility............................. 19
Superpave Compaction Specifications........................................................22
C om putational M odels........................... ......... ................................................ 22
Laboratory Tests for Determining Asphalt Pavement Thermal Properties...........25
Thermal Conductivity ........... ..... ......... ................. ........................... 25
Specific Heat.................. .. ...................................................... 26
Therm al D iffusivity...................................................................................26
CHAPTER 3 MODELING OF HEAT TRANSFER DURING ASPHALT PAVING ............. 27
Introduction ..................................................... .... ............ ................... 27
The Paving Process..........................................27
T he M odel ....................................... ..................................... ................... 28
Assumptions .......................................... 28
G overning E quations........................................................... ................... 30
N um erical Solution ....................................................................................... 31
The Deforming Grid.....................................................................................................32
Validation ......................................................................................................................... 33
The Effects Of Compaction................................................................................34
C onclu sions ....... . ............................. ..... ... ..................................... .....................36
CHAPTER 4 THERMAL PROPERTIES.............................................................................37
Introduction ......................................... 37
M ethodology.............................................. ........... ...... ....... .............. ....... .38
O verview ....... ................................................ ....................... ............... 38
Sensitivity Analysis Of Pavement Thermal Properties................... .......... 38
Pavem ent Cooling M odel............................................... .....................39
R esu lts ................................................................................................... 4 0
C onclu sions............................................................................................ 40
Determination of Appropriate Thermal Property Testing Procedures............. 41
M ix D esign ........................................................................ ... 41
Compaction of Slab Specim ens ....................................... .................... 42
Compaction of Cylindrical Specimens....................................................43
Asphalt Pavement Thermal Property Measurements.................. .............. 45
Slab Cooling Method for Thermal Diffusivity of Asphalt Concrete ........ 45
Thermal Probe Method for Thermal Conductivity of Asphalt Concrete ..48
Evaluation of Compaction Processes............................................................49
Results of Thermal Testing .............. ....................... 50
D ensity A nalysis......................... .. . ................ ... ........ ................... 50
T herm al D iffusivity................................................................. ....................51
Therm al Co nductivity ............................................................. ................... 52
Effect on Asphalt Pavement Cooling Rates.................................................. 53
C onclu sion s ................................ ................................................................ 55
Com paction...................... .............................. . ......................... 55
Therm al D iffusivity............................................................... ..................... 55
Therm al Co nductivity ............................................................ .................... 57
Effect on Asphalt Pavement Cooling Rates .................... ..................... 57
CHAPTER 5 COMPACTION PROPERTIES ..................................... 59
Introduction ..................... ..... . .................... 59
Sum m ary of M ixture Types ........................................................ ..................... 59
L aboratory M ixes......................................................................................... 60
Field M ixture Properties........................................................ ..................... 61
Field D ata and Sam pling .................................................................................... 61
L aboratory C om paction .............................................................. ..................... 64
C om paction Procedure.......................................................... ..................... 65
D ata An alysis................................................. 66
R esu lts .................................. ...... ..................... ................ ..................... 6 9
Shear Stress ......................... ... ....................69
L aboratory M ixtures........................................................ ..................... 69
Field Mixtures................................... 72
P ow er ....................................................................................... ................... 74
Laboratory M ixtures............................................................................. 74
Field Mixtures................................................................................................... 75
Optimal Compaction Temperature....... .... ... ....................... 76
CHAPTER 6 ASPHALT PAVEMENT COOLING TOOL....................................................79
D escription ................................................................ ...... ............................ 79
Therm al Properties............................................... .................. ........................ 80
Field V erification..................................................................... ....................... 82
CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS............................................ 83
Conclusions ..................................................................................................... 83
Recom m endations............................................................................................ 84
REFEREN CES .................................................................................. .................................. 85
APPENDIX A PAVEMENT COOLING MODELS
APPENDIX B MATERIAL PROPERTIES
APPENDIX C THERMAL TESTING PROCEDURES
APPENDIX D ENVIRONMENTAL MODELS
APPENDIX E LABORATORY THERMAL DATA
APPENDIX F FIELD VERIFICATION