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