roadway design presentation

CITY OF SASKATOON GREEN STREET PROGRAM

Presented byDuane GuentherProject EngineerCity of Saskatoon

May, 2010

Acknowledgements COS Staff PSI Technologies Inc. University of Saskatchewan (SCETI)

Highlights

Background Design Issues Existing Conditions Solutions 2007 to 2009 Test Sections 2010 Test Sections Preliminary Findings Future Plans

Background

Asphalt Recycling History Asphalt Rubble

Stockpiled Landfilled

Asphalt Millings Stockpiled Added to new Hotmix

Background

Concrete Recycling History Concrete Rubble

Stockpiled Landfilled

Background

In Place Recycling Re-uses in place materials to rebuild the road

Typically includes some stabilization 31st Street Isabella Street Rylston Road Jasper Avenue Idylwyld Service Road Albert Avenue

Background

Rubble Processing Standard for many municipalities

Typically processed to a 3” minus gradation Used as a sub-base material Blends a variety of rubble materials Typically used primarily by own forces or sold to

contractors working on municipal projects.

Background

Other recycling applications Millings

Used as aggregate in hotmix Adds stiffness to mix Increases the variability

Can be used with rejuvinators in Cold Mix Stockpiles may need to be reprocessed to uniform

gradation

Background

Other recycling applications Crushed Concrete

Used as aggregate in new concrete Variability in cement content and other impurities Only for non-structural concrete

Background

Other recycling applications General Applications

Working platform in water & sewer trenches Bedding aggregate Surfacing aggregate

Lanes Temporary cut repairs

Low settlement fill where compaction is not easily attained

Design Issues Flexible System – City of Saskatoon

Dry CBR specification Granular systems

Structure determined by traffic level ESALS CBR Nomograph Road Classification

Design Issues Granular system does wet up over time

Fine content increases over time due to water pumping

412

607

397

548

377

502

420

613

409

553

389

508

428

619

421

561

403

514

432

625

431

567

411

522

0

250

500

750

Optimum MC (6.5%) Ambient Dry (3.7%) Optimum MC (6.6%) Ambient Dry (4.0%) Optimum MC (6.7%) Ambient Dry (3.2%)

Granular Base Base w/5% Subgrade Fines Base w/10% Subgrade Fines

Dyn

amic

Mod

ulus

(MP

a):

Med

ium

Str

ess S

tate

10 Hz 5 Hz 1 Hz 0.5 Hz

Design Issues Effect of Additional Fines

6.4%

8.8%

10.7%

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

Granular Base Base w/5% Subgrade Fines Base w/10% Subgrade Fines

Wat

er In

take

(per

cent

)

Design Issues Effect of Additional Fines

250

199181

0

50

100

150

200

250

300

Granular Base Base w/5% Subgrade Fines Base w/10% Subgrade Fines

After Climatic Durability

Pea

k St

reng

th (

kPa)

Design Issues Flexible System – City of Saskatoon

Assumptions Free Draining – Always Dry Unchanging granular system

Existing Conditions Overall Site Conditions

Urban environment Watering

Existing Conditions Overall Site Conditions

Fixed Location Aggregate is becoming more scarce

Existing Conditions Overall Site Conditions

New Development locations Converted wetlands Poor quality subgrade

Chart Based on Subgrade CBR Value of 5.0 and Design Life of 15 YearsCLASSIFICATION LOCAL COLLECTOR INDUSTRIAL ARTERIAL FREEWAY

              A B C  

ADT <1,500 1,000 - 12,000 N/A 5,000 - 30,000 >30,000

TRUCK TRAFFIC 0.5% 2% N/A 5% 8%

WIDTH (M) 9 10 11 14 15 15 2/10.8 2/7.2 14.4 N/A

CROWN HEIGHT (MM) 130 145 160 190 200 200 Min. 2.5% Min. 2.5% 200 As per

          project

HMA (MM) 40 45 50 75 80 80 110 100 90 design

          and soils

BASE (MM)           investigation.

Min. CBR 60 110 125 125 150 150 150 150 150 150  

SUBBASE (MM)            

Min. CBR 25 100 100 150 225 225 350 300 300 300  

SUBGRADE (MM) 150 150 150 300 300 300 300 300 300  

Existing Conditions Overall Site Conditions

Solutions Material Separation

Geotextiles Allow water to pass through No material transfer

Solutions Additional Stress Distribution

Geotextiles Bridging Additional resistance to tension

Solutions Drainage Structures

Geotextiles Water collection Drainage Pipe

Drainage Rock Gap graded Moisture break

Solutions Geotextiles

Add $3 to $10 per square meter to construction Drainage aggregate

Can add $10-$15 to cost if not included in regular structure

Structural Drainage Layer With Virgin Aggregate, adds $10 - $15

Use Recycled Aggregate instead to maintain low cost

Solutions Drainage Layer Design

Green Street Test Sections Objectives

Develop Standard for Processing Asphalt and Concrete Rubble Protocols for receiving rubble material Determine what is the optimum gradation (s) available Encourage optimal use of the processed material

Green Street Test Sections Objectives

Develop Standard for Processing Asphalt and Concrete Rubble

0.01 0.1 1 10 100

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

City of Saskatoon Crushed Rock Granular Base Type 1 PCC

Type 2 PCC Type 3 PCC Type 4 PCC

Sieve Size (mm)

Per

cent

Fin

er T

han

Green Street Test Sections Objectives

Develop Methodology for constructing roads with recycled materials Compaction methods for the various materials Matching Material characteristics with location in road

structure Possible addition of cement / emulsion for increased

material characteristics

Green Street Test Sections Objectives

Develop Design Method for roadways that meets needs of urban environment. Drainage capability Material Characteristics determine placement location Design based on critical state failure rather than ESAL’s

Esals vs CBR Nomographs were designed for thick pavement structures

Green Street Test Sections

Green Street Test Sections Material Characterization

100

267

8

90

32

198

0

50

100

150

200

250

300

Conve-ntional

'09 19mm(GW)

'09 19mm(OGBC)

'09 19mm (GW) '09 25mm(OGBC)

Cold In-Place

Granular Base Crushed PCC Crushed RAP In-Place Recycled

Con

duct

ivit

y (µ

S/cm

)

357

637

267

147

357417

0

100

200

300

400

500

600

700

Conve-ntional

'09 19mm(GW)

'09 19mm(OGBC)

'09 19mm (GW) '09 25mm(OGBC)

Cold In-Place

Granular Base Crushed PCC Crushed RAP In-Place Recycled

Wat

er I

ntak

e (m

L)

Green Street Test Sections Material Characterization

Green Street Test Sections Material Characterization

47

9 63

1

94

2

15

46

15

09

20

25

99

0

48

0 64

7 92

4

15

11

13

93

17

99

94

1

48

8 64

5 91

2

15

43

118

6

13

66

85

3

49

1 65

4 93

3

16

00

112

5

12

35

81

5

0

500

1000

1500

2000

2500

Conve-ntional

'09 9mm (Fines) '09 19mm (GW) '09 19mm(OGBC)

'09 19mm (GW) '09 25mm(OGBC)

Cold In-Place

Granular Base Crushed PCC Crushed RAP In-Place Recycled

Dyn

amic

Mod

ulus

(MP

a):

Low

Str

ess S

tate

10 Hz 5 Hz 1 Hz 0.5 Hz

29

5 40

2 60

9 72

7

114

0

16

86

75

5

Sa

mpl

e F

ail

ed

41

3 55

9 72

7

10

49

14

82

71

2

Sa

mpl

e F

ail

ed

40

5 59

0 74

0 88

5 110

0

62

2

Sa

mpl

e F

ail

ed

40

7 59

9 74

7

82

8 97

6

58

8

0

500

1000

1500

2000

2500

Conve-ntional

'09 9mm (Fines) '09 19mm (GW) '09 19mm(OGBC)

'09 19mm (GW) '09 25mm(OGBC)

Cold In-Place

Granular Base Crushed PCC Crushed RAP In-Place Recycled

Dyn

amic

Mod

ulus

(MP

a):

Hig

h St

ress

Sta

te

10 Hz 5 Hz 1 Hz 0.5 Hz

Green Street Test Sections Marquis Drive – Rotomix existing surface

Green Street Test Sections Marquis Drive – Remove Rotomixed

surface & stockpile on site

Green Street Test Sections Marquis Drive – Excavate and remove

subgrade

Green Street Test Sections Marquis Drive – place drain pipe

Green Street Test Sections Marquis Drive – first layer of geotextiles

Green Street Test Sections Marquis Drive – crushed concrete drainage

layer

Green Street Test Sections Marquis Drive – geotextile separation layer

Green Street Test Sections Marquis Drive – Rap & rotomixed surface

as new base

Green Street Test Sections Marquis Drive – SS-1 emulsion with

rotomixing on top 100mm

Green Street Test Sections Marquis Drive – compacted surface ready

for paving

Green Street Test Sections Marquis Drive – paving complete

Green Street Test Sections Heritage Crescent

Green Street Test Sections Attridge Drive

Green Street Test Sections Kenderdine Road

Green Street Test Sections 8th Street

Green Street Test Sections Test Section Structural Validation

1.101.50

0.95

1.49

#N/A

1.93

0.58 0.47 0.44 0.380.69

0.28

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

115th Street(Conv. Drainage

Rock)

Kenderdine Road 8th Street Field House Road ArlingtonBack Lane

Marquis DrivePeak

Sur

face

Def

lectio

n (m

m)

Pre Construction Post Construction

COS Target <0.75mm

1.63

2.21

1.42

2.40

#N/A

2.67

0.89 0.71 0.66 0.581.02

0.42

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

115th Street(Conv. Drainage

Rock)

Kenderdine Road 8th Street Field House Road ArlingtonBack Lane

Marquis DrivePeak

Surf

ace D

eflec

tion (

mm

)

Pre Construction Post Construction

COS Target <0.75mm

2010 Green Street Test Sections

Test Section Locations Kenderdine Road Phase 2 Wilkinson Crescent Adolf Way

Test Section Design Entire granular structure as processed concrete

Preliminary Findings Processing

Increased number of materials reduces overall fines produced

Able to produce a number of specialized materials Changes need to be made to material

specifications to allow these materials

Preliminary Findings Construction

Larger concrete aggregate is better received by field staff

Vibratory compaction not recommended for recycled concrete within drainage

Residents favour the use of recycled material Changes need to be made to material

specifications to allow these materials Typical testing parameters used locally are not

valid

Preliminary Findings Design

Testing data indicates good performance of recycled material

Different design procedure needed other than CBR / ESAL design

Capability to design for different materials is needed

Preliminary Findings Test Section Economic Validation

Typi

cal A

rteria

l Stru

ctur

e

Arteria

l with

Dra

inag

e Roc

k su

bstit

uted

for S

ub-B

ase

Arteria

l with

Cru

shed

Con

cret

e su

bstit

uted

for S

ub-b

ase

Typi

cal A

rteria

l Stru

ctur

e with

Non

-Stru

ctur

al S

ubdr

ain

$-

$1.00

$2.00

$3.00

$4.00

$1.98

$2.94 $2.34 $2.40

$3.95

$2.10 $1.67 $1.71

Roadway Material Cost

Cost/Year of Design LifeCost/Year of Actual Life

Cost

/ Square

Mete

r

Future Plans Specifications

Material specifications should be modified to allow for recycled material

Quality Control tests need to be changed In order for testing agencies to get apparatus to

do different tests the local demand has to be present

In order for municipalities to require new tests there needs to be a familiarity with the testing results

Future Plans Aggregate Use

Capability is there to have little demand for virgin aggregates in Public Works Maintenance operations Requires a change in mindset of personnel Requires a change in internal policy of

administration Determination the best use of Recycled

aggregates Industry is pushing for millings to be used in

Hotmix instead Poor understanding of material science within

municipal agencies

Future Plans Aggregate Use

Specification change could allow new development to include a drainage layer economically

Determination the best use of Recycled aggregates Industry is pushing for millings to be used in

Hotmix instead Poor understanding of material science within

municipal agencies therefore training required

Future Plans Design Standards

Design method required to meet the needs of urban traffic patterns Critical Load driven Related to material mechanical characteristics Measureable results post construction

THANK YOU!