RECYCLING OF ASPHALT PAVEMENTS

1. A Seminar Presentation on
RECYCLING OF ASPHALT PAVEMENTS
Submitted By
TANUPRIYA PATEL
222111515
Under the guidance of
Dr. P.K. Agarwal
Department of Transportation Engineering
MANIT Bhopal
December 7, 2022

2. CONTENTS
 Introduction
 Recycling Methods
 Literature Review
 Conclusions
 References

3. The bituminous pavement rehabilitation alternatives are mainly overlaying, recycling and reconstruction.
In the recycling process the material from deteriorated pavement is reused in fresh construction.
It is reported that recycled mix has higher resistance to shearing and scuffing.
The process of recycling involves mixing of the RAP, fresh bitumen, rejuvenators and new aggregates.
Different recycling methods are now available to address specific pavement distress and structural needs.
INTRODUCTION

4. RECYCLING METHODS
 Recycling Location
In place vs Plant
 Recycling Process
Cold vs Hot
 Recycling Extent
Surface vs Full depth

5. 1. Hot in-place recycling
 The pavement intended to be recycled is heated to a higher temperature using
suitable heating arrangement. This facilitates easier removal of materials.
 After heating, the pavement surface is scarified to the required depth. Further,
depending on the requirement fresh aggregate and binder are added.
 The material is mixed well and compacted to the required thickness. As this
process consumes less time, least disruption to traffic is caused.
 The transportation cost is less, as materials need not be taken away. Machinery
required for this purpose being bulky in nature, sufficient right-of-way is
required. This becomes an important consideration for in-place recycling within
the city areas.

7. Cold In-place recycling
 In cold in-place recycling process first, the pavement is scarified with a scarifier.
The scarified material is crushed to the required gradation.
 The required amount of fresh aggregates and binder in cold form (emulsion or
cutback) is added. It is compacted and left for aeration. During this process
additives like cement, quick lime, fly ash may be used.
 The cold mix recycling takes care of local geometric correction, correction of
pavement distresses like surface cracks Being an in-situ process the hauling cost is
considerably low.
 The air quality related problems during construction is almost negligible as
compared to hot mix process.
 Moisture content (when bitumen emulsion is used) needs to be given importance as
it influences gradation control, mixing and workability of recycled mix to a large
extent.

8. Cold in place recycling Kandhal, P.S. 2019

9. Hot Central Plant Recycling
 In this process, RAP is combined with required quantity of bituminous binder, and
fresh aggregates in a hot mix plant.
 The resultant mix is heated to an elevated temperature and mixed thoroughly. The
hot mix is transported to paving site, placed, and compacted to the required
compaction level.
 The mix properties and performance is high comparable to that of virgin mix. And
also have noted that the quality control in this process is better when compared to
hot in- place recycling.
 As RAP is susceptible to moisture, care needs to be taken while storing it.
 Less workspace is required for laying the recycled mix, hence this is suitable for
the roads where the right of way is somewhat restricted.
 The RAP should not be exposed to extremely high temperature as it causes
pollution due to smoke emission.

10. Cold Central Plant Recycling
 The material removed from an existing asphalt pavement is transported to a
central location – either on the project site or an existing asphalt plant.
 The cold plant, like the CIR process, uses either asphalt emulsion or foamed
bitumen as a binding agent.
 Once the material and the binding agent are mixed, it can be discharged into a
truck and taken to a project for paving.
 An advantage of the CCPR process is the ability to use existing materials at an
asphalt plant.

11. LITERATURE REVIEW
SI
NO.
Authors and Year Paper Title Inferences
1. Satish Chandra & Ambika
Behl, 2019
Recycling Of
Pavements -A
Sustainable Process
For Rehabilitation
And Upgrading
1. The required DBM
thickness as per
conventional design was
135 mm, but was reduced to
90 mm.
2. Use of foam stabilized
technique enabled
utilization of 80% of
recycled aggregate and
about 60% less bitumen for
construction of pavement.

12. SI
NO.
Authors and Year Paper Title Inferences
2. Krupa S. Sharma &
Prof. Ashok Patel,
2018
Recycling of Asphalt
Pavements
The use of recycled
material as WMM
after investigating
and then adding the
missing sieve size
material.
( LOS Angeles ,
impact value & shape
tests)

13. CONCLUSIONS
 The recycling process resulted in construction time saving, minimal use of virgin
aggregates, less transportation costs and huge reduction in carbon emission.
 The bituminous layers made by hot recycling may serve as wearing or base course
layers.
 This study has also shown that research on the microstructure of RAP is limited,
researchers are encouraged to take up on the microstructure of RAP and other
properties in order to fully understand the material.
 The Recycled material can be used as filling material without doing any analysis and
tests in low lying areas.

14. References
 Sharma, Krupa S., and Ashok Patel. "Recycling of Asphalt Pavements."
(2017). International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056 Volume: 05 Issue: 01 | Jan-2018 p-ISSN: 2395-0072
 Chandra, Satish & Behl, Ambika. (2019). Recycling Of Pavements -A
Sustainable Process For Rehabilitation And Upgrading.

15.  Dagliya, Monika, and Rewa Bochare. "Recycling Bitumen from Dismantled Road-
A Case Study." International Journal of Engineering Research & Technology
(IJERT) http://www.ijert.org ISSN: 2278-0181 IJERTV9IS060734 Vol. 9 Issue 06,
June-2020
 Costel, Plescan & Plescan, Elena. (2015). ASPHALT PAVEMENT RECYCLING.
Bulletin of the Transilvania University of Brasov. 8(57). 256. Bulletin of the
Transilvania University of Braşov CIBv 2015 • Vol. 8 (57) Special Issue No. 1 –
2015
 .https://web.iitd.ac.in/~akswamy/Published%20Articles/Bituminous%20pavement
%20recycling.pdf
 https://www.fhwa.dot.gov/pavement/recycling/rap/
 https://www.fhwa.dot.gov/publications/research/infrastructure/structures/97148/rap
131.cfm
 https://vaasphalt.org/pavement-recycling/

16. THANK YOU