Kingston University London

Vahid AYAN, S. Masoud N AZADANI, Joshua R OMER, Mukesh C LIMBACHIYA

IAU, Tehran, Iran

WASCON 2012

Gothenburg, SWEDEN, 30 May–1 June 2012

Kingston University London

o Materials

o Employed Protocol

o Performed Tests

o Conclusions

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Kingston University London Page 3

100%RCA

80%RCA+20%RAP

50%RCA+50%RAP

20%RCA+80%RAP

100%RAP

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Links between aggregate properties and performance

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Rating of toughness potential test methods for evaluating

recycled aggregates

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Employed Protocol Significance levels of traffic, moisture and temperature

combinations on aggregate performance potential

Temperature

Condition

Moisture

Condition

Traffic

High Medium Low

Freezing High 4 4 3

Low 4 3 2

Non Freezing High 3 2 2

Low 3 2 1

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Employed Protocol Recommended tests and test parameters for levels of

intended use in recycled aggregates

TESTS

Traffic H M H L M L

Moisture H L H L H L H H L L H L

Temperature F F F F NF NF F NF NF F NF NF

Toughness/Abrasion

Micro-Deval, MD < 5 % < 15 % < 30 % < 45 %

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Desired Test Performed Tests

Micro-Deval

Los Angeles Abrasion Degradation

Performed test results should be transformed into the equivalent

MD test value.

Correlation is not easily achieved because at present there are

few published correlations between LAA and MD values.

These correlations suffer from low reliability.

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Los Angeles Abrasion (LAA)

Aggregate Test Result

100%RCA LAA=31%

20%RAP+80%RCA LAA=29%

50%RAP+50%RCA LAA=29%

80%RAP+20%RCA LAA=28%

100%RAP LAA=28%

Weight losses in LAA tests decreased as the level of

replacement of RAP with RCA increased.

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Degradation

0

10

20

30

40

50

60

70

80

90

100

0,01 0,1 1 10 100

Perc

enta

ge P

assin

g

Particle Size (mm)

Before Compaction

After Compaction

30 8 4 16 3/8 3/4 1 1/2 200 100 50 2 3

0

20

40

60

80

100

0,01 0,1 1 10 100

Perc

enta

ge P

assin

g

Particle size (mm)

Before Compaction

After Compaction

30 8 4 16 3/8 3/4 1 1/2 200 100 50 2 3

Sieve analysis of

RAP compacted

sample

Sieve analysis of

RCA compacted

sample

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Chart showing the likely range of MD values corresponding to LAA< 35% (Rangaraju

and Edlinski, 2008)

The author’s tests showed that all aggregates with LA abrasion of less than 35% had

the MD of less than 23.5% (Ayan, 2011)

LAA vs. MD

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LAA vs. MD

L.A. Abrasion vs. Micro-Deval (Williamson, 2005)

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Performance Potential Based on Toughness

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•Low degradation of 100%RAP caused the mixes containing RAP

to have higher toughness potential.

•Degradation of 100%RCA is increased by the process of

extraction of RCA, which may mean that cement mortar attached

to the aggregates is crushed or partly detached from the

aggregates causing weakness in RCA. This is manifested in the

results of the other toughness tests such as LAA and MD.

•In summary, it is seen in that for all tested materials, the

significance level was always either 1 or 2. This implies that from

the viewpoint of toughness, the materials investigated here would

be appropriate for unbound subbases for medium traffic in non

freezing condition. Also they are suitable for low traffic situations

with low moisture and freezing weather.

Conclusions

Kingston University London Page 15

VAHID AYAN

Azad University (IAU) ,

Faculty of Engineering

Department of Civil Engineering

Islamshahr, Tehran, Iran

vahidayan@gmail.com

Tel. +98 (0)912 175 0669

ICSW 2011

STRC