Construction Quality Index
Construction Conference 2010
1
About the Research

FDOT contracts PR608014 and PR1575813

Research organizations
9 Applied Research Associates, Inc.
9 University of Florida

Research reports
p
available online
9 http://www.dot.state.fl.us/research-center/Completed_StateMaterials.shtm
2
What is a Construction Quality
Index?

CQI is
i a rational
ti
l measure off the
th overallll quality
lit off a
constructed facility
9 Determine the quality of the individual components
9 Link together to obtain a composite index

CQI as developed
d
l
d iis not b
based
d on ffundamental
d
l
material properties directly related to long term
pavement performance

The subject CQI is, rather, a measure of specification
compliance
3
Why do we need a CQI?

Increased need for “quality-driven” workmanship

There is a need for quantifying quality and implementing
appropriate measurement techniques and approaches
4
Research Objectives

Develop a practical and effective pavement CQI that is...
9 Implementable without modification to the
Department’s current test and measurement system
9 Addresses material, structural, smoothness, and other
construction requirements as defined in current
specifications
9 Applicable
A li bl ffor new and
d rehabilitated
h bilit t d pavements
t
5
Technical Approach
Task 1:
Literature Review
Task 2:
Model Formulation
Task 3:
Model Development
Task 4:
Model Evaluation
Task 5:
Documentation
6
Model Formulation

Goals
9 Based on FDOT specifications
9 Practical, transparent and easily understood
9 Address quality factors for major types of
construction
9F
Feature
t
simple,
i l readily-implementable
dil i l
t bl
relationships and logic
9 Modular
7
Acceptance Quality Characteristic

Inherent pavement construction characteristic:
9 Thought
Th
ht to
t affect
ff t future
f t
pavementt performance
f
9 Under the control of the contractor
9 Measurable at or near the time of construction
Model Formulation
Layer 1
Layer 2
CQI of individual AQC:
( cqi
q )AQC = PWL( AQC )
.
.
.
CQI of individual layer:
CQI layer =
∑w
AQC
⋅ (cqi )AQC
AQC
CQI of pavement:
Layer n
CQI pavement =
∑W
layer
⋅ CQI layer
layers
y
http://www.dot.state.fl.us/research-center/Completed_StateMaterials.shtm
9
Expert Panel Meetings
Sheet 1 of 1
FDOT CONSTRUCTION QUALITY INDEX

Expert panel of stakeholders
developed CQI weighting
factors
EXPERT PANEL RATING SHEET
RIGID PAVEMENT
Name:
Location:
Date:
Affliation:
Florida Department of Transportation
Construction Industry
Consultant
Academia
Other
8
7
Rigid Pavement System Components
Which factor has the greater influence on quality?
6 5
4
3
2
1 2
3
4
5
6
7
8
9 Factor
Stabilized Subgrade
Treated Permeable Base
PCC
Treated Permeable Base
PCC
PCC
8
7
Stabilized Subgrade
Which factor has the greater influence on quality?
6 5
4
3
2
1 2
3
4
5
6
7
8
9 Factor
LBR
Thickness
Thickness
8
7
Cement Treated Permeable Base
Which factor has the greater influence on quality?
6 5
4
3
2
1 2
3
4
5
6
7
8
9 Factor
Water-Cement Ratio
Cement Factor
Cement Factor
8
7
Asphalt Treated Permeable Base
Which factor has the greater influence on quality?
6 5
4
3
2
1 2
3
4
5
6
7
8
9 Factor
Gradation
8
7
PCC
Which factor has the greater influence on quality?
6 5
4
3
2
1 2
3
4
5
6
7
8
9 Factor
Compressive Strength
Profile Index
Slump
Thickness
Water-Cement Ratio
Profile Index
Slump
Thickness
Water-Cement Ratio
Slump
Thickness
Water-Cement Ratio
Thickness
Water-Cement Ratio
Water-Cement Ratio
Concerning:
9 Contractors
9 DOT
9 FHWA
9 Academia
Factor 9
Embanmkent
Embankment
Embankment
Stabilized Subgrade
Stabilized Subgrade
Treated Permeable Base
Concerning:
Factor 9
Density
Density
LBR
Concerning:
Factor 9
Gradation
Gradation
Water-Cement Ratio
Concerning:
Factor 9
Asphalt Binder Content
Concerning:

Three meetings
Th
ti
h
held
ld d
during
i
Summer ’06
Factor 9
Air Content
Air Content
Air Content
Air Content
Air Content
Compressive Strength
Compressive Strength
Compressive Strength
Compressive Strength
Profile Index
Profile Index
Profile Index
Slump
Slump
Thickness
10
Components of Flexible
Pavement System

Embankment

Subgrade
Subg
ade

Base Course

Superpave

Friction Course
CQI
FP
= W E ( cqi ) E + W SG ( cqi ) SG + W BC ( cqi ) BC
+ W SP ( cqi ) SP + W FC ( cqi ) FC
11
Superpave AQCs
cqiiSP = wP (#8) PWLP (#8) + wP (# 200 ) PWLP (# 200 ) + wPb PWLPb
+ wVa PWLVa + wP ( Gmm ) PWLP ( Gmm )
12
Layer Weights – Flexible
CQI ppavement =
∑W
layer
y
⋅ CQI layer
y
layers
13
AQC Weights – Friction Course
CQI layer =
∑w
AQC
⋅ (cqi )AQC
AQC
FC
C5
FC 9.5
9 5 and FC 12
12.5
5
14
AQC Weights – Structural Layer
CQI layer =
∑w
AQC
⋅ (cqi )AQC
AQC
15
AQC Weights – Supporting Layers
Subgrade
Base Course
CQI layer =
∑w
AQC
⋅ (cqi )AQC
AQC
Embankment
16
Components of a Rigid Pavement
S t
System

Embankment

Subgrade

B
Base
C
Course

PCC Slab
CQI
RP
= W E ( cqi ) E + W SG ( cqi ) SG + W BC ( cqi ) BC
+ W PCC ( cqi ) PCC
17
Layer Weights – Rigid Pavement
System
CQI ppavement =
∑W
layer
y
⋅ CQI layer
y
layers
18
AQC Weights – PCC Slab
CQI layer =
∑w
AQC
⋅ (cqi )AQC
AQC
19
AQC Weights – Permeable Base
CQI
= ∑ w ⋅ (cqi )
layer
AQC
AQC
AQC
ATPB
CTPB
20
AQC Weights – Supporting Layers
CQI
= ∑ w ⋅ (cqi )
layer
AQC
AQC
AQC
Subgrade
Embankment
21
Model Evaluation

Representative real world projects
9 Flexible/rigid
9 Rehabilitation/new

Recent
9 Current methods and specifications
9 Data available in LIMS

Project
j
managers
g
requested
q
to p
provide a level of
satisfaction or rating based on specification compliance
22
Model Evaluation for Flexible
P
Pavements
t

37 projects identified with sufficient data
9 20 ‘good’ and 17 ‘poor’
9 8 new construction projects
gp
projects
j
9 29 resurfacing
23
CQI Rating for Flexible Projects
Good Projects
Poor Projects
1.00
CQI (As
sphalt Layers only)
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
Project
24
CQI Rating for Flexible Projects

A CQI of approximately 0.80 appears to discriminate between good
and poor flexible projects

Average CQI for ride number
9 Good: 0.94
9 Poor: 0.51

Average CQI for density
9 Good
- Friction course: 0.88
- Structural layer: 0.85
9 Poor
- Friction course: 0
0.58
58
- Structural layer: 0.64
25
Model Evaluation for Rigid Pavements

14 projects provided
9 Only 7 projects had sufficient data for statistical
analysis
9 All 7 projects rated as good by district engineers
9 Because of lack of a larger representative sample, a
definitive
de
e comprehensive
co p e e s e assess
assessment
e was
as not
o
appropriate
26
Model Evaluation for Rigid Pavements
1.00
0 90
0.90
0.80
PCC CQI
0.70
0.60
0.50
No poor projects evaluated
0.40
0.30
0.20
0 10
0.10
0.00
1
3
5
7
Project
27
CQI Calculator
28
CQI Calculator
29
Pavement Performance

CQI is not based on fundamental properties inherent to
pavement p
p
performance

CQI is a measure of specification compliance
30
Contractor CQI
1.00
10
3
0.90
8
Asphallt CQI
0.80
1
2
1
1
0.70
0.60
2
6
1
6
4
1
2
Noncom
mpliance Rate, %
8
3
3
0.50
0
Contractor
Density Failure Rate
Air Void Failure Rate
Historical noncompliance rates from 2005 to 2007
Avg CQI
CQI max/min
31
Summary and Conclusions

CQI threshold of 0.80 appears to discriminate between
good and p
g
poor flexible rehabilitation p
projects
j

Rigid projects were limited and did not consider whole
construction spectrum
p
9 All good projects had a CQI > 0.80
9 Need
eed to
oe
expand
pa d e
evaluation
a ua o to
o include
c ude a larger
a ge poo
pool
projects

What’s next?
9 Continue to evaluate CQI
9 Develop implementation plan
32
Q
33