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Laboratory Testing of Reclaimed Asphalt
Pavement - Crushed Rock for Footpath and
Pavement Applications
Jegatheesan Piratheepan and Arul Arulrajah
Swinburne University of Technology, Melbourne, AUSTRALIA.
Outline of the Presentation
Background
Laboratory Testing
Results
Specifications
Conclusion
Background
Solid Waste Materials
Approximately 32 million tonnes of solid waste is generated in Australia.
Approximately 14 million tonnes comprises construction and
demolition (C&D) materials, of which about 50% is recycled.
Stockpiles in Australia:
Reclaimed asphalt pavement – 1.2 million tonnes
Waste rock – 3.3 million tonnes
Recycled glass – 1 million tonnes
Crushed concrete – 8.7 million tonnes
Reclaimed Asphalt Pavement
Crushed Concrete
Crushed Rock
Crushed Glass
Alternative Materials
Traditional quarry materials are commonly used in pavement and
footpath bases/sub-bases
The need for utilising alternative materials in road and footpath
construction
o Scarcity of natural resources
o Minimise the quantity of waste materials/area for landfill
Pavement Base (Class 1 & 2)
Pavement Sub-base (Class 3 & 4)
Asphalt Wearing Surface 25 mm
100-250 mm
150-300
mm
Footpath Base
Asphalt Wearing Surface
100 mm compacted
depth
35 mm
Cross-section of a
footpath
Cross-section of an
unbound Pavement
Reclaimed Asphalt Pavement (RAP)
RAP is the old asphalt pavement that has been removed
RAP is mainly recycled into new hot mixed asphalt
100% RAP does not produce a product of base course quality
o Inconsistent
o Low CBR
o Poor shear strength
Allowed up to 20% with virgin aggregates in road base (in USA)
RAP – 20 mm
Waste Rock (WR)
Excavated rock (basalt floaters) from construction sites
A mixture of high and low quality
May be used in road base and sub-base
Can be blended with other waste materials (e.g. RAP, crushed
concrete, crushed glass)
Waste Rock – 20 mm
Laboratory Testing
RAP Blended with WR
Study of geotechnical characteristics of RAP blended with WR.
Maximum particle size of 20 mm
100RAP, 50RAP/50WR, 30RAP/70WR and 100WR.
Particle size distribution
Modified Proctor compaction
Particle density
Water absorption
California Bearing Ratio (CBR)
Los Angeles abrasion
pH test
Organic content
Flakiness index and
Permeability tests
Laboratory Experiments
Laboratory Test Results
Sample Description 100RAP 50RAP/
50WR
30RAP/
70WR 100WR
Recycled Asphalt (RAP) by weight (%) 100 50 30 0
Particle density – Coarse (Mg/m3) 2.4 2.23 2.13 2.86
Particle density – Fine (Mg/m3) 2.4 1.71 1.84 2.85
USCS Classification SW SW GW GM-SM
Water absorption – Coarse (%) 8.6 4.6 3.84 3.32
Water absorption – Fine (%) 22.4 5.4 5.52 4.72
Organic content (%) 5.1 1.57 2.95 1.04
pH 7.6 9.80 9.65 10.92
Fine content (%) 3.4 3.5 3.8 10.2
Flakiness index 22.34 29.48 34.3 19
Hydraulic conductivity (m/s) 3.5×10-7 1.77×10-6 2.35×10-6 2.7×10-
7
Los Angeles abrasion loss 42 28 32 21
California Bearing Ratio (%) 30 40 48 121
Compaction (Modified) Max dry density (Mg/m3) 2.040 2.250 2.145 2.225
OMC (%) 8.25 9.0 11.25 9.25
Specifications
Specifications for Footpath Base and Pavement
Sub-base Materials
VicRoads Specifications
(section 812 and 820)
Physical Property
Pavement Sub-base Footpath Base
Class CC3 Class CC4
Liquid Limit (%)(max) 35 40 35
Plasticity Index (max) 10 20 10
California Bearing Ratio (%)(min) 80 20 40
Los Angeles Abrasion Loss (max) 40 45 60
Flakiness Index (max) 35 35 35
Conclusions
All the blends, except 100RAP, meet the local council requirements
in the state of Victoria, Australia for usage as a footpath base material
RAP blended with WR up to 50% can be used for footpath base
applications
100WR satisfies the requirements as sub-base material for
pavements
Thank You