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TRANSCRIPT
Preparing for Concrete
Pavement Construction
ASCP Forum 14 March 2016 Todd Myers Director/Owner TSM Civil Project Management
President ASCP
TOPICS
1. Subgrade Preparation
2. Mix Design
3. Mix Consistency
4. Stringline Setup
5. Paver Operation
6. Motivated Trained Team
PREPARATION FOR CONCRETE
PAVEMENTS
ASCP Forum 14 March 2016
Extend Select/subgrade beyond edge slab
Foundation fully compacted
Trimmed to grade
Stable materials
Keep obstructions clear
Ensure pits lower than subgrade
Trench drains not under track
1. SUBGRADE PREPARATION
ASCP Forum 14 March 2016
Clear Track line
Well-Graded Single-Sized Gap-Graded
Use of Aggregates and Water for Concrete by Rick Bohan,
Portland Cement Association, Skokie, IL
Paste Qty
Well graded – Workable – Uniform materials
2. MIX DESIGN
ASCP Forum 14 March 2016
RMS R83 Grading Requirement
o Combined Grading submitted with mix
o Table R83.1
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
Min 38% ‘Sand’
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
0
10
20
30
40
50
60
70
80
90
100
26.5 19.0 13.2 9.5 6.75 4.75 2.36 1.18 .600 .300 .150 .075
Pe
rce
nt
Pa
ss
ing
Sieve Size
R83 Combined Grading % Passing Curve Table R83.1 - Nominated Grading
MIN MAX
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
0
10
20
30
40
50
60
70
80
90
100
26.5 19.0 13.2 9.5 4.75 2.36 1.18 .600 .300 .150 .075
Pe
rce
nt
Pa
ss
ing
Sieve Size
(Old) R83 Combined %Passing Grading Curve Table R83.1
MIN MAX
Mix #1 Mix #2
Both Mixes Fully Conforming. But will they Perform?
ASCP Forum 14 March 2016
0
1
13
24
16
4
8
14 14
4
2
0
1
15
17
23
11
6 6
10
8
2
0
5
10
15
20
25
26.5 19.0 13.2 9.5 4.75 2.36 1.18 .600 .300 .150 .075
Pe
rce
nt
Reta
ine
d
Sieve Size
% Retained Graph
Mix #1 Mix #2
Classic ‘Haystack Mix’ Maximum Density
Rather than plotting % Passing lets plot %Retained
2. MIX DESIGN (CONT)
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
‘Optimised Graded Concrete Pavement’ (OGCP)
0 1
13
24
16
4
8
14 14
4
2
0 1
15
17
23
11
6 6
10
8
2
0
5
10
15
20
25
26.5 19.0 13.2 9.5 4.75 2.36 1.18 .600 .300 .150 .075
Pe
rce
nt
Re
tain
ed
Sieve Size
% Retained Graph OGCP Limits
Mix #1 Mix #2
OGCP Developed by Dr Tyler Ley Oklahoma State University
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
‘Shilstone’ Coarseness – Workability Chart
[2.36mm Sieve]
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
Mix #1 65.5, 41.1
Mix #2 49, 33.0
20
25
30
35
40
45
-90 -80 -70 -60 -50 -40 -30
Wo
rka
bil
ity
%
Coarseness Factor %
'Shilstone' Coarseness- Workability Chart
Zone IV Excess
fines, Segregation
Zone I Gap
Zone II
Zone III Finer mixes
Zone V Rocky
ASCP Forum 14 March 2016
2. MIX DESIGN (CONT)
How did Mixes #1 & #2 Perform?
Remember Fully Conforming Mixes
Mix #1
• Excessive slurry
• Edges dropped off
• Segregated easily
Mix #2
• Very harsh rocky mix
• Insufficient slurry
• Poor edge finish, tearing
• Like paving rocks
WARNING! Combined Grading alone is NOT sufficient to ensure a good paving mix
ASCP Forum 14 March 2016
3. MIX CONSISTENCY
Uniformity – Within the batch • Pre blend materials • Aggressive mixing – Central Mix or Agitators • Mixing time achieve homogenous mass (>3.5mins) • Mixer uniformity testing
Uniformity – Batch to batch • Accurate weighing • Conforming materials • Accurate moisture contents – eg probes • Modern plant • Good plant & loader operator
ASCP Forum 14 March 2016
3. MIX CONSISTENCY (CONT)
Batch Process
• Full conformance aggs before delivery to BP
• No intermingling stockpiles
• Hard well compacted base for stockpiles
• Aggs always wetter than SSD (ie Sprinklers)
• Use agg moisture probes
• kW/Hydraulic meter to monitor slumps
• Loading profile of materials
• Mixers maintained well
ASCP Forum 14 March 2016
4. STRING LINE SETUP
• Pre-plan the position, avoid obstacles
• Option single S/L & cross slope sensor
• Accurate survey setout
• Trained stringline crew
• Line tension consistency
• Double check – Visual
• Keep traffic away
• Ride can be no better than stringline
ASCP Forum 14 March 2016
4. STRING LINE SETUP
• Typical String Set- up
ASCP Forum 14 March 2016
5. PAVER OPERATION
Aim is to not stop
Steady consistent speed – Match BP
output
Clear track-line
Machine setup- Attack angle
Good tip man – No bulldozing
Adequate number trucks
Maintained, well clean each day
ASCP Forum 14 March 2016
5. PAVER OPERATION (CONT)
Standard Paving
ASCP Forum 14 March 2016
5. PAVER OPERATION (CONT)
‘Outboard’ Paving
ASCP Forum 14 March 2016
6. MOTIVATED & TRAINED TEAM
Pre-planning before start
• Work procedures,
• Inspection & Test Plans (ITP’s)
• Lot Checklist
• Lot tracking, registers & diagrams
• Wet & dry test requests
• Flowchart the process- Who does what, when?
ASCP Forum 14 March 2016
6. MOTIVATED & TRAINED TEAM
Flow Chart the process- examples
Batch new trial
mixPerform Tests
Results
OK?
Analysis
results
Obtain
Approval
Authority to
batch
No
Yes
Prior to paving Trial
File to:
File to:Lot Records
R8
3 C
lau
ses
4.2
Foremans Daily CheckSheet to be Completed Batch Dockets Input to
concrete register
Wet Testing
of Concrete
BP copy to be
collected daily
1 copy with truckDay Sheet
(Air content, slump, temp,
Cylinders and Flex Beams)
File to: Batch
Records
Tipping of
Concrete
Tipping &
Paving recordsFile to:Lot
Records
Paving of
ConcreteSlab dip
measurements
Paving Dip
Sheet
File To : Lot
Records
File to:Lot
Records
Add daily volume into register
Enter Wet Testing into Register
ASCP Forum 14 March 2016
6. MOTIVATED & TRAINED TEAM (CONT)
Testing Organisation • Choose wisely
• Lab setup
• Experienced personel
• Data transfer process for results
• Agree timetable for results
• Audits – Process, test methods
ASCP Forum 14 March 2016
6. MOTIVATED & TRAINED TEAM (CONT)
Every person plays a part- team approach
ASCP Forum 14 March 2016
PREPARATION FOR CONCRETE
PAVEMENTS
Thankyou