6. 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
7. 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.
8. 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
9. Other recycling applications
Crushed Concrete
Used as aggregate in new concrete
Variability in cement content and other impurities
Only for non-structural concrete
10. 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
11. Flexible System – City of Saskatoon
Dry CBR specification
Granular systems
Structure determined by traffic level
ESALS
CBR Nomograph
Road Classification
12. 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
DynamicModulus(MPa):
MediumStressState
10 Hz 5 Hz 1 Hz 0.5 Hz
13. 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
WaterIntake(percent)
14. Effect of Additional Fines
250
199
181
0
50
100
150
200
250
300
Granular Base Base w/5% Subgrade Fines Base w/10% Subgrade Fines
After Climatic Durability
PeakStrength(kPa)
15. Flexible System – City of Saskatoon
Assumptions
Free Draining – Always Dry
Unchanging granular system
16. Overall Site Conditions
Urban environment
Watering
17. Overall Site Conditions
Fixed Location
Aggregate is becoming more scarce
18. 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 Years
CLASSIFICATION 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
21. Additional Stress Distribution
Geotextiles
Bridging
Additional resistance to tension
22. Drainage Structures
Geotextiles
Water collection
Drainage Pipe
Drainage Rock
Gap graded
Moisture break
23. 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
25. 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
26. Objectives
Develop Standard for Processing Asphalt and
Concrete Rubble
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.01 0.1 1 10
PercentFinerThan
Sieve Size (mm)
City of Saskatoon Crushed Rock Granular Base
Type 1 PCC Type 2 PCC
Type 3 PCC Type 4 PCC
27. 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
28. 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
49. Test Section Locations
Kenderdine Road Phase 2
Wilkinson Crescent
Adolf Way
Test Section Design
Entire granular structure as processed concrete
50. 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
51. 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
52. 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
53. Test Section Economic Validation
$1.98
$2.94
$2.34 $2.40
$3.95
$2.10
$1.67 $1.71
$-
$0.50
$1.00
$1.50
$2.00
$2.50
$3.00
$3.50
$4.00
$4.50
Typical Arterial
Structure
Arterial with
Drainage Rock
substituted for
Sub-Base
Arterial with
Crushed Concrete
substituted for
Sub-base
Typical Arterial
Structure with
Non-Structural
Subdrain
Cost/SquareMeter
Roadway Material Cost
Cost/Year of Design Life
Cost/Year of Actual Life
54. 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
55. 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
56. 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
57. 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
