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