This document discusses different methods for recycling bituminous materials. It examines: 1. Using high percentages of reclaimed asphalt pavement (RAP) in recycled asphalt mixtures, finding stiffness and strength were similar to conventional mixtures. 2. Replacing fine aggregate in concrete with RAP, which increased workability but decreased strength. 3. Using different rejuvenators in RAP mixtures, which improved cracking resistance and moisture sensitivity compared to control mixtures, by reducing stiffness of aged binders. The conclusion is that high RAP contents up to 60% are possible with rejuvenators improving workability, and more research is needed on RAP concrete mixtures.

1. Lebanese University
Faculty of Technology - Saida
 Prepared by:
Israa Hussein
 Supervised by:
Dr.Saly Serhal

2. Constituents of Bituminous Materials
2
Aggregates
Filler
Bituminous Binders
95%
2%
3%

3. Sources of Bituminous Binders
How we
can get
Bitumen
?
Natural
Deposit
3
Refining
Crude Oil Bitumen is the vacuum
residue of the crude oil

4. Composition of Bitumen
Carbon 87%
Hydrogen 6%
Sulfer 5%
Nitrogen 1%
Oxygen 1%
0
20
40
60
80
100
4

5. Uses of Bitumen
Paving
85%
Roofing
10%
Other
Uses
5%
 Resources used for the production of
bituminous materials will lasts.
 In 2007: Average World Consumption
of Bitumen was 102 million tons per year.
 Rehabilitation and maintenance of
pavement materials costs time and
money.
5

6. What is the solution
in this case?
Recycling reduces the use of
non-renewable materials
(aggregates, fuel).
Recycling are less expensive
than rehabilitation and
maintenance this will
reduces the cost of raw
materials and the cost of
waste transport.
6

7. How can I recycle bituminous
materials?
Several studies were carried up by
researchers, in order to use recycled
materials in different forms, wont
that be more efficient?
.
7

8. Outline
1
• Use of high percentages of reclaimed asphalt
pavement (RAP) in recycled asphalt mixtures.
2
• Replacement of Fine Aggregate in Concrete
with RAP.
3
• Use of different rejuvenators in RAP mixtures.
8

9. 1. Using RAP with High Percentages in Asphalt Pavement
S20R60 S12R40
Two
Mixtures
9
Tests carried out
 Stiffness Modulus
 Indirect Tensile Strength
 Fatigue Cracking
S20R60
Means 20 mm maximum
aggregate size containing
60% RAP
Compare with
control mixture
13/22
penetration
grade
bitumen
S20 mix
without RAP
60/70
penetration
grade
bitumen

10. Results of Stiffness Modulus
 The results for
the cores
indicate a slight
increase in
stiffness
values over
time, except for
S12R40 mixtures
between 12 and
24 months.
10
Stiffness moduli and densities as function of specimens and
field cores, at 20 °C
 The stiffness
modulus of the
recycled mixtures
are between the
results obtained for
the S20 standard
mix with 13/22 and
60/70 penetration
grade bitumen
 The average
modulus of S12R40
mixtures is slightly
lower than that of
S20R60 mixtures.
 The density
levels are very
similar for all
specimens.

11. 11
Results of indirect tensile strength
 The strengths of
the recycled
mixtures are close
to that of the high
modulus mixture
with 13/22
penetration grade
bitumen.
 Tests carried out on
cores at 6 and 12
months show that
indirect tensile
strengths are
similar and lower
than the values for
the recycled mixture
laboratory
specimens.
Indirect tensile strength and densities as function of
specimens and field cores, at 15°C

12. Results of Fatigue Resistance
 These results
confirm that the
fatigue behaviors
of the recycled
mixtures and the
control mixture
with 13/22
penetration grade
bitumen are very
similar.
12
Strain in function of the number of cycles
 The mixture
with 60%
RAP content
having the
highest
dynamic
modulus.

13. 2. Replacement of Fine Aggregate in Concrete with RAP
 Workability Test
 Water Absorption Test
 Density of Concrete
 Compression Test
13
Mix proportion used

14. Results!
The slump increased when RAP content
was above 60%. This increase in
workability is due to the bitumen
content which does not absorb water.
The excess water not absorbed by the
particles cause the fluidity leading to
higher workability.
The specimen with 40% RAP
content showed the highest
absorption value of 6.5% higher
than the control mixture.
14

15. Results!
The density decreases with
increase in fine aggregate
replacement with RAP.
Compressive strength decreases
with increase in RAP content for
all the curing days.
15

16. 3. Use of Different Rejuvenators in RAP Mixtures
The use of more RAP
the rigidity of the asphalt
mixture
workability of the mixture
+
hardness the compaction
process.
increase
reduce
Why we need
to add
rejuvenators
?
16

17. mixtures with
commercial
rejuvenators.
5%
RAS
19%
RAP
13%RAP
and
5% RAS
Control
Mixtures
Compare their
performance
with
Tests carried out
 Hamburg wheel tracking test
Dynamic modulus test
The overlay test
17

18. Results!
Hamburg Wheel Tracking
Test
 The addition of rejuvenators with
RAP and/or RAS improved the
cracking resistance and the
moisture sensitivity, compared to
the control mixtures.
 Rejuvenators can reduce the
stiffness of the aged binder from
the recycled materials.
Dynamic Modulus Test
 Rejuvenators may affect the
stiffness characteristic of
mixtures only over lower loading
frequency levels.
18
What does it study?
measures changes of the
viscoelastic stiffness of the
asphalt mixtures due to the
addition of rejuvenators.

19. Results!
The Overlay Test
 The rejuvenators reduced the
stiffness of the aged binder from
the recycled materials so that they
improved cracking resistant of
mixtures.
19
The best performance was achieved
by the 19% RAP mixture
The overlay test was
used to evaluate the
cracking resistance of
the asphalt mixtures.

20. So, what do you
conclude?
20
1. Using high rate of RAP (up to 60%)
is possible.
2. More research works are required
to ascertain the true behaviour of
RAP concrete such as reducing the
water cement ratio with increase in
RAP replacement.
3. Adding rejuvenators to the RAP
improves its workability.

21. 21