Post on 30-May-2018
transcript
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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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
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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