Project TX 0-5566
Strategies to Improve and
Preserve Flexible Pavement
at Intersections
UTEP
- Soheil Nazarian
- Imad Abdallah
Project Duration September 08 – August 10
1
Problem
Rural intersections are failing early


Damage to small vehicles
Motorists lose control of their vehicles
2
Causes for these
failures




High traffic volumes
Heavy truck traffic
Heat generated from vehicles waiting in
queue
Repeated vehicle turning movements and
hard stops
3
Ranked Rural Issues Raised
by TxDOT District Staff
REF: Jolanda Prozzi, Robert Harrison, Jorge A. Prozzi, (2005), “Defining and Measuring Rural Truck Traffic Needs in
Texas,”Center for Transportation Research, The University of Texas at Austin, Research Report 0-4169-2
4
Distresses (Example 1)
original
profile
weak asphalt layer
shear plane
5
Distresses (Example 2)
original
profile
asphalt layer
weak subgrade or underlying layer
subgrade
deformation
6
Bottom Line
Intersections are
designed as a part of the
roadway but are not
subjected to the same
conditions
7
Task
1. Information
Search
2. Understanding
and Documenting
Extent of
Problems and
Solutions in Texas
Work Plan
3. Selection of
Candidate Sites
for In-Depth
Evaluation
Activity Highlights
Work Product
• A comprehensive Literature Review
• A document of practices for mitigating rutting at
intersections worldwide
• A matrix of solutions, when they are effective, their
advantages and disadvantages, their economical feasibility
•
•
•
•
• A document of typical intersections with problem
• A catalog of sources of problems
• A catalog of effective and ineffective solutions
• A comparison of TxDOT solutions with those from other
states and countries
Surveying Districts
Reviewing Forensic Reports
Interviewing District Personnel and site visits
Interviewing CST Personnel
• An in depth statistical and trend analysis of
results from Task 2 to categorize typical
problems
• At least twelve sites that cover the inference space of the
problems, pavement types, environmental conditions,
subgrade types etc. for in depth field and laboratory
evaluation
• A catalog of solutions based on the type of the problem,
and the field and laboratory testing results
4. Thorough
Forensic Study of
Candidate Sites
• Structural and Functional evaluation of sites
• Coring and Sampling
• Laboratory tests of Pavement Materials
• Recommending solutions
• Conducting thorough structural design of the
existing and recommended Solutions
• Life Cycle Cost Analysis of Solutions
5. Preliminary
Guideline Based
on Results from
Tasks 2 through 4
• Develop a Comprehensive Decision tree
- to guide TXDOT personnel through the
process of field and Laboratory evaluation
intersections
- to select the most appropriate rehabilitation
solutions
• A flow chart that will lead TXDOT personnel through
steps necessary for selecting best rehabilitation solutions
for a given intersection
6. Develop Final
Design and
Construction
Guideline
• Incorporate the outcome of Task 5, the
remaining outcome of field work and feedback
from PMC in a final guideline
• A document that can be used as a guideline by TxDOT
personnel
• An electronic version of the document with hyperlinks
that provide additional information to TxDOT personnel
7. Develop an
Expert System
• Incorporate the outcome of Task 5 and 6 in an
expert system shell to readily guide TxDOT
personnel in determining the best solution
• A software that will ask a series of simple if-then
questions from users to guide them through the process of
selecting the best solution, determining the most appropriate
mix or mineral, and suggestions for reconstruction of the
sections
8. Recommend
changes to
TxDOT Policies
9. Submit Reports
• Based on the outcome of all tasks,
recommend changes to the TxDOT 2004
Specifications
• a technical memorandum at the end of each
task
• A final report documenting all work
performed, method used, and results achieved.
• A Project Summary Report (PSR)
8
Schedule
9
10
Final
Product
Outline
Problem, Schedule, Final Product
 Background (Review of Literature)
 Goal (Problem Statement)
 Objective
 Methodology
 Tasks

Review of Literature
(Task 1)
Asphalt Pavement Alliance
Maryland Asphalt Association
National Asphalt Pavement Association
National Center for Asphalt Technology
Colorado Department of Transportation
Canada
South Africa
New Zealand Common
Illinois DOT Types of
Remediation
Nevada DOT Distress
Oregon DOT
Action Plan
Kansas DOT
Most Common
Distress
Rutting
Structural Rutting
Instability Rutting
Surface/Wear Rutting
Other Common
Distresses
Shoving
Bleeding
Fatigue
Cracking
Raveling
Remediation
Strategies
• Mill and Overlay with Asphalt Concrete
• Rut Filling Using Spray Patching, Micro-Surfacing
• Grinding and Precision Milling
• Whitetopping (Conventional and Concrete Inlay)
• Ultra-Thin Whitetopping
• Thin Composite Whitetopping (TCW)
• Roller Compacted Concrete (RCC)
• Hot in Place Recycling (HIR)
• Cold in Place Recycling (CIR)
Action Plan
1. Evaluate pavement performance problems and
determine the cause of major distress.
2. Ensure the pavement is structurally adequate.
3. Select and implement a cost-effective, technically
sound pavement mitigation approach with
appropriate materials selection and mix designs.
4. Practice proper construction techniques with
quality assurance.
Example 1 After
SUPERPAVE Mix
17
Other Examples
Permeable
Frictionless
Coarse (PFC)
Surface Course
designed to
Superpave
Specifications
Coarse Matrix
High Binder
(CMHB)
Heavy Duty
Binder Course
Larger Stone
Binder Course
18
Other Examples
Stone-Matrix
Asphalt (SMA)
Stone Mastic
Asphalt
Thin
Composite
Whitetopping
19
Goal

To provide solutions that can be
readily and economically carried out
considering:
location of the project
 construction practices
 type of potential or actual damage at
intersections.

20
Methodology
(Expert System)
Knowledge Base (Facts and Rules)
User Interface
Facts
Inference Engine
(Draw Conclusions)
Expertise
Explanation (Advice and Reasoning)
21
Task
1. Information
Search
Forensic Study of
•
Activity
Candidate
Sites Highligh•
e
• A comprehensive Literature Review•
•
Tasks
2. Understanding
and Documenting
Extent of
Problems and
Solutions in Texas
3. Selection of
Candidate Sites
for In-Depth
Evaluation
4. Thorough
Forensic Study of
Candidate Sites
•
•
•
•
5. Preliminary
Guideline Based
p
Surveying
onDistricts
Results from
i
Reviewing
Forensic
Reports
Tasks 2 through 4
Interviewing District Personnel ands
Interviewing CST Personnel
6. Develop Final
•
Design and
re
Construction
f
• An in depthGuideline
statistical and trend ana
results from Task 2 to categorize typic
problems
•
7. Develop an
e
Expert System
p
• Structural and Functional evaluatio
• Coring and Sampling
• Laboratory tests of Pavement Mat
• Recommending
solutions
8. Recommend
•
• Conductingchanges
thorough
structural
des
to
re
existing and
recommended
TxDOT
Policies SolutionsS
• Life Cycle Cost Analysis of Solutio
22
Task 2. Understanding and
Documenting Extent of Problems
and Solutions in Texas




Surveying TxDOT Districts
Reviewing Forensic Reports
Interviewing district personnel and
site visits
Interviewing CST personnel
23
District Interviews
Texas’ Districts Map
Amarillo
Showing Districts with Answer
District:
Austin
Bryan
Houston
Atlanta
Paris
Lubbock
Abilene
Laredo
Date:
April 13th, 2009
April 14th, 2009
April 15th, 2009
April 20th, 2009
April 22nd, 2009
April 27th, 2009
April 28th, 2009
April 29th, 2009
Contact Person:
Mike Arillano
Catherine Hejl
Mike Alford
Miles Garrison
Mykol Woodruff
Tracy Crumby
Brian Crawford
Jo Ann Garcia
Childress
Wichita
Falls
Lubbock
Paris
Atlanta
Fort
Worth
Abilene
Dallas
Tyler
Brownwood
Odessa
Waco
San
Angelo
Lufkin
Bryan
Austin
El Paso
Beaumont
Houston
San
Antonio
Yoakum
Laredo
Corpus
Christi
Districts with minor
distresses at intersections
Pharr
Districts with high
distresses at intersections
Task 3. Selection of
Candidate Sites

A least twelve sites that cover following criteria:


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
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Type of distress observed (instability rutting vs. structural rutting)
Type of subgrade (clayey vs. sandy)
Pavement structure (two-course surface treatment vs. with HMA)
Traffic volume (rural vs. urban)
Environmental condition (east Texas vs. west Texas)
Preference will be given to sites that are
scheduled for maintenance, rehabilitation or
reconstruction.
25
Site Visited

Atlanta






Showing Districts with Answer
fm 497 – fm 155
fm 149 – fm 315
US 259
Laredo
fm 1472
US 83
Texas’ Districts Map
Amarillo
Childress
Wichita
Falls
Lubbock
Paris
Atlanta
Fort
Worth
Abilene
Dallas
Tyler
Brownwood
Odessa
Waco
San
Angelo
Lufkin
Bryan
Austin
El Paso
Beaumont
Houston
San
Antonio
Yoakum
Laredo
Corpus
Christi
Districts with minor
distresses at intersections
Pharr
Districts with high
distresses at intersections
Task 4. Forensic Study





Forensic investigation
Structural strength
Aggregate structure
Correct Asphalt Binder grade
Good construction practices
Visited five sites and performed a thorough
Investigations
Site Survey, FWD, GPR, DCP, Coring, Lab Testing
27
Sites Visited and Investigated

Atlanta




fm 497 – fm 155
fm 149 – fm 315
US 259
Laredo


fm 1472
US 83
28
Task 5. Preliminary
Guidelines Based on Results
Develop a Comprehensive Decision Tree



To guide TxDOT personnel through process of
field and laboratory evaluation intersections
To select most appropriate rehabilitation
solutions
29
Remediation Alternatives
Flexible Pavement Treatment Selection Matrix
Maintenance
Microsurfacing
Fog Seal
Crack Seal
Sand Seal *
Slurry Seal *
Ultra Thin Wearing
Coarse
Chip Seals
Surface Treatment
Hot in Place
Recycling
Cold in Place
Recycling
HMA & RAP Overlay
Hot Mix Overlay
HMA & Recycled
Asphalt Shingles
(RAS) Overlay
PCC Overlay (Thick)
Ultra-Thin
Whitetopping *
Full Depth
Reclamation
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3 / 8 - 1 in
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Moisture Intrusion
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Structural Rutting
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Surface
Rutting
Asphalt Layer
D
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Distress
Instability
Rutting
Shoving
Fatigue
Cracking
Base
Rehabilitation
PCC
< 3 / 8 in
Treatment
Subgrade
HMA Surfacing
Structural
Rutting
30
Task 6. Develop Final Design
and Construction Guidelines


A document that can be used
as a guideline by TxDOT
personnel
An electronic version of
document with hyperlinks that
provide additional information
to TxDOT personnel
31
Task 7. Develop an Expert
System
Incorporate an expert
system shell.

With simple If-Then
questions.
 Guide through process of
selecting best solution.

32
Use of the Expert System
Intersection
Condition
Traffic
Condition
Remediation
Strategies
Life Cycle Cost
Analysis
Best Cost
Effective
Alternative
Other
Consideration
33
Expert System
Variables Window
34
Expert System
Logic Block Window
Expert System
Logic Block and Rule View Window
Expert System
Corvid Browser
Expert System
Corvid Browser
Expert System
Corvid Browser
Task 8. Recommend
Changes to TxDOT Policies

Based on the outcome of all
tasks, recommend changes
to TxDOT 2004
Specifications, if necessary.
40
Demonstrate
Prototype and Show
Preliminary Guideline
Prototype
Guideline
41
Thank you
42