Self-healing technology is a new field within material technology. It represents a revolution in materials engineering and is changing the way that materials behave. Incorporating self-healing technology into the road design process has the potential to transform road construction and maintenance processes by increasing the lifespan of roads and eliminating the need for road maintenance. By decreasing the unnecessary premature ageing of asphalt pavements, self-healing asphalt can reduce the amount of natural resources used to maintain road networks, decrease the traffic disruption caused by road maintenance processes, decrease CO2 emissions during the road maintenance process and increase road safety. In addition to environmental savings, self-healing materials have the potential to deliver significant cost savings for road network maintenance across the EU.. There are three main self-healing technologies available for asphalt pavement design: Nanoparticles, Induction heating and Rejuvenation. This study reviews all three options and outlines the future development of self-healing asphalt technology

1. 1
Asphalt as a Healing Material
Collaboration By :
SHAIKH MOHAMMAD FAISAL JAVED ALAM

2. Outline of this presentation
} Abstract
} History of Roads
} Need for Asphalt as self healing
} Methods to improvement self healing property of Asphalt
Roads
} Laboratory test
} Practical application of heat induction on Asphalt Roads
} Porous Asphalt Roads
2
Fig.1.1.2:
6th
Century BC.
A Roman street in Pompeii
Fig.1.1:
Roman ROAD
Cross Sectional Details
Fig.1.1.3:
6th
Century BC.
A Roman street in Pompeii
Fig.1.1.4.:
6th Century BC.
Via dell'Abbondanza, the
main street in Pompeii.
Fig.1.1.1:
3RD century BC
Greek street, Porta Rosa, Velia
- Italy

3. Abstract:
Self-healing technology is a new field within material technology. It
represents a revolution in materials engineering and is changing the way
that materials behave.
Incorporating self-healing technology into the road design process has the
potential to transform road construction and maintenance processes by
increasing the lifespan of roads and eliminating the need for road
maintenance.
3
Fig.1.2.1:
Aerial view of Asphalt Road
By decreasing the unnecessary
premature ageing of asphalt
pavements, self-healing asphalt
can reduce the amount of natural
resources used to maintain road
networks, decrease the traffic
disruption caused by road
maintenance processes, decrease
CO2 emissions during the road
maintenance process and increase
road safety. In addition to
environmental savings, self-
healing materials have the
potential to deliver significant cost
savings for road network
maintenance across the EU..
There are three main self-healing
technologies available for asphalt
pavement design:
1. Nanoparticles,
2. Induction heating and
3. Rejuvenation.
This study reviews all three
options and outlines the future
development of self-healing
asphalt technology
History of roads
Roman road
The Roman roads were physical infrastructure vital to the maintenance and
development of the Roman state, and were built from about 300 BC through
the expansion and consolidation of the Roman Republic and the Roman
Empire. They provided efficient means for the overland movement of armies,
officials, and civilians, and the inland carriage of official communications
and trade goods.
Roman roads were of several kinds, ranging from small local roads to broad,
long-distance highways built to connect cities, major towns and military
bases. These major roads were often stone-paved and metaled, cambered for
drainage, and were flanked, by footpaths
bridleways and drainage ditches. They were laid along accurately surveyed
courses, and some were cut through hills, or conducted over rivers and
ravines on bridgework. Sections could be supported over marshy ground on
rafted or piled foundations.
After romans road there were some other construction type of roads
introduced such as Metcalf Method, Teleford Method etc.
Fig.1.3.1:
6th Century BC. A Roman street in Pompeii

4. 4
Water Bond Macadam Roads…
Macadam is a type of road construction, pioneered by Scottish
engineer John Loudon McAdam around 1820, in which single-
sized crushed stone layers of small angular stones are placed in shallow
lifts and compacted thoroughly. A binding layer of stone dust (crushed
stone from the original material) may form; it may also, after rolling, be
covered with a binder to keep dust and stones together. The method
simplified what had been considered state of the art at that point.
Fig.1.4.1: Typical Cross Section
of water bond macadam road
Fig.1.4.2: Typical Cross Section of
water bond macadam road
McAdam's method was
simpler, yet more effective
at protecting roadways: he
discovered that massive
foundations of rock upon
rock were unnecessary, and
asserted that native soil
alone would support the
road and traffic upon it, as
long as it was covered by a
road crust that would
protect the soil underneath
from water and wear.
Asphalt roads….
Asphalt roads sometimes called flexible pavement due to the nature in
which it distributes loads, has been widely used since the 1920s. The
viscous nature of the bitumen binder allows asphalt concrete to sustain
significant plastic deformation, although fatigue from repeated loading
over time is the most common failure mechanism. Most asphalt surfaces
are laid on a gravel base, which is generally at least as thick as the asphalt
surfaces are laid directly on the native subgrade. In areas with very soft or
expansive subgrades such as clay or peat, thick gravel bases or
stabilization of the subgrade with Portland cement or lime may be
required.
Concrete roads….
Concrete surfaces are created using a concrete mix of Portland cement, coarse
aggregate, sand and water. In virtually all modern mixes there will also be
various admixtures added to increase workability, reduce the required amount
of water, mitigate harmful chemical reactions & for other beneficial purposes.
The material is applied in a freshly mixed slurry, and worked mechanically to
compact the interior and force some of the cement slurry to the surface to
produce a smoother, denser surface free from honeycombing. The water
allows the mix to combine molecularly in a chemical reaction
called hydration.One of the major advantages of concrete pavements is they
are typically stronger and more durable than asphalt roadways. They also can
be grooved to provide a durable skid-resistant surface. A notable disadvantage
is that they typically can have a higher initial cost, and can be more time-
consuming to construct. This cost can typically be offset through the long life
cycle of the pavement.
Most asphalt surfaces are laid on a
gravel base, which is generally at
least as thick as the asphalt layer,
although some 'full depth' asphalt
Polypropylene and polyester
geosynthetic have also been used for
this purpose
Concrete pavement can be
maintained over time utilizing
a series of methods known as
concrete pavement restoration
which include diamond
grinding, dowel bar retrofits,
joint and crack sealing, cross-
stitching, etc.
Fig.1.4.3:
Typical Cross Section of Concerte Road

5. 5
Need for asphalt as self healing
Care and Sealing….
Every three to five years, asphalt pavement must be resealed to prevent
cracking. Sealers must be applied and then the surface left alone for two to
three days before cars can drive on the surface. Resealing the asphalt surface
every three to five years will cost money and time.
Fig.1.5.1: Shows Cracked Wearing surface
of Asphalt road
Fig.1.5.2:
Shows Damaged surface of Asphalt road
Fig.1.5.3:
Shows Damaged surface of Asphalt road
Pothole…
A pothole is a structural failure in
a road surface, caused by failure
primarily in asphalt
pavement due to the presence of
water in the underlying soil
structure and the presence of
traffic passing over the affected
area. Introduction of water to the
underlying soil structure first
weakens the supporting soil.
Traffic then fatigues and breaks
the poorly supported asphalt
surface in the affected area.
Continued traffic action ejects
both asphalt and the underlying
soil material to create a hole in
the pavement.
Crack...
When asphalt is not laid properly,
it is prone to cracks and pitting.
Issues such as uneven pavement
surfaces, inadequate mixing and
laying pavement over previous
cracks are all reasons cracks will
occur.
Methods to improve self healing property of asphalt roads
There are three main self-healing technologies available for asphalt
pavement design:
1. Nanoparticles,
2. Induction heating and
3. Rejuvenation.
This study reviews all three options and outlines the future development
of self-healing asphalt technology
Nanoparticles
Nano rubber are used in the bitumen mix to improve the physical & mechanical
properties of the binders and, as such, to improve in-situ performance of an
asphalt pavement. Rubber modifiers in the form of nanoparticles have also
been used to improve the healing properties of asphalt mastic.
The clear advantage of Nano rubber as a modifier is its double role; it can
improve asphalt mix durability and also act as self-healing modifier in the mix.
However, the disadvantage of polymer-based modifiers is their thermodynamic
incompatibility with asphalt binder as a result of the large differences in
material density, polarity, molecular weight and solubility between the polymer
and the asphalt. This can result in delamination of the composite during
thermal storage, which is not readily apparent and adversely affects the asphalt
mix when it is used.

6. Laboratory test:
A beam of asphalt mastic with steel fibres is first produced and then is
completely broken (vertically), placed together again at the matching breakage
surface and then warmed up via induction. After the induction healing, the
mastic beam appeared to be whole again in such a way, so that as a singular
object it could be broken again. This complete procedure could be repeated for a
total number of six to seven times, while the required force to break the beam
again (after healing) remained at least 70% of the initial breaking force. In
another study the effect of the induction treatment on the mix and also on the
binder is investigated. This shows that no excessive effect on binder hardening
occurs. This because of the absence of oxygen inside the mix.
6
Induction Heating:
Induction heating in asphalt pavement design was pioneered by Minsk. He
developed and patented the first electrically conductive asphalt pavement using
graphite as a conductive medium for the purpose of melting snow and ice on
roadway surfaces by induction heating. The induction process operates by
sending an alternating current through the coil and generating an alternating
electromagnetic field. When the conductive asphalt specimen is placed under
the coil, the electromagnetic field induces currents flowing along the conductive
loops formed by the steel fibres. This method can be repeated if damage
returns.. Although induction healing can enhance the self-healing capacity of
asphalt pavement, an adverse effect is that heating the asphalt mix ages the
bitumen. Furthermore, overheating (>110C) the asphalt mix can cause binder
swelling and drainage, which adversely affects pavement performance. at
present Inductive heating is the most progressive self-healing technology for
asphalt pavements reported to date. This technology has transitioned from
laboratory to site in a short period of time (3 years)
Fig.1.6.1: Shows
Damaged
surface of
Asphalt road
Practical application of Heat Induction on asphalt road:
The newly developed Induction Technique makes use of a completely different,
more direct method. During the production of the asphalt mixture, a small
amount of highly refined steel filaments (or fibers ) is added. It are these steel
fibers within the asphalt mortar (or mastic) that makes it possible to heat the
asphalt layer via induction.
During the induction heating process, the iron molecules inside the steel fibers
are subjected to a rapid changing magnetic field, causing the iron material to heat
up. It is a well-known technique used in many kitchens today: an induction
cooking plate directly heats the bottom of the pan, instead of transferring contact
heat via an electrical cooking plate. So by induction, it is not the cooking plate
itself that becomes warm, but the base of the pan. Also, less energy is lost
compared to heating via gas burning.
Fig.1.6.2 & 3 : Shows Damaged repair using Heat induction on
asphalt road by induction heating vehicle.
Fig.1.6.2:
Induction Heating
Vehicle
Fig.1.6.3:
Induction Heating
Vehicle

7. Heat Induction on asphalt road is a completely harmless technique that
can be applied with great capacity. By applying this technique to asphalt
(with steel fibers inside the mortar), the steel fibers become hot. They in
turn yield their heat to the surrounding mastic.
This way, the mastic (or mortar) inside the asphalt mixture can be
intensively heated equally as well as evenly and directly across the entire
thickness of the asphalt surface layer – causing the mastic (or mortar) to
momentarily melt. The fine cracks inside the mortar will then ‘flow close’
again and the asphalt is reset at the original state. This technique is
developed together with the Technical University of Delft,
The great advantage with this method is that the energy (or heat) is applied
directly to the mastic (or mortar). That is exactly the part of the asphalt
wherein the fine hair cracks are formed in the course of time. Thus there is
hardly any loss of energy during the transfer of heat via induction.
The desired result (or transfer of required energy to the right location) is
already obtained before the stones have had the chance to become warm
indirectly. Only the effective part of the asphalt mixture needs to be heated
7
Porous asphalt roads :
In the natural environment, rainfall sinks into soil, filters through it, and
eventually finds its way to streams, ponds, lakes, and underground aquifers.
The built environment, by way of contrast, seals the surface. Rainwater and
snowmelt become runoff which may contribute to flooding. Contaminants are
washed from surfaces directly into waterways without undergoing the
filtration that nature intended.
A typical Porous Pavement has an open-graded surface over an
underlying stone recharge bed. The water drains through the porous asphalt
and into the stone bed, then, slowly, infiltrates into the soil. Many
contaminants are removed as the storm water passes through the porous
asphalt, stone recharge bed, and soils through filtration and microbial action.
Fig.1.7.1:
Shows Porous
Asphalt surface
Absorbing 300
Gallons of water in
four Minutes
Fig.1.7.2:
Shows Damaged
Asphalt surface
with Healing Effect
by Heat Induction
on Asphalt surface.

8. 8
what can porous asphalt do?
Porous asphalt pavements are of great interest to site planners and public-
works departments. With the proper design and installation, porous asphalt can
provide cost-effective, attractive pavements with a life span of more than
twenty years, and at the same time provide storm-water management systems
that promote infiltration, improve water quality, and many times eliminate the
need for a detention basin. The performance of porous asphalt pavements is
similar to that of other asphalt pavements. And, like other asphalt pavements,
they can be designed for many situations.
How does it work?
The technology is really quite simple. The secret to success is to provide the
water with a place to go, usually in the form of an underlying, open-graded
stone bed. As the water drains through the porous asphalt and into the stone
bed, it slowly infiltrates into the soil. The stone bed size and depth must be
designed so that the water level never rises into the asphalt. This stone bed,
often 18 to 36 inches in depth, provides a tremendous sub base for the asphalt
paving. To view a cross section of a porous asphalt pavement.
What does it cost?
Special features such as the underlying stone bed are more expensive than
conventional construction, but these costs are more than offset by the
elimination of many elements of standard storm-water management systems.
On those jobs where unit costs have been compared, a porous asphalt pavement
is generally the less-expensive option. The cost advantage is even more
dramatic when the value of land that might have been used for a detention
basin or other storm-water management features is considered.
How long do these pavements last, and how long do they remain porous?
Even after twenty years, porous pavements show little if any cracking or
pothole problems. The surface wears well. Porous asphalt retains its ability to
handle rain water for many years. One of the best-known porous parking lots,
located at the Walden Pond State Reservation in Massachusetts, was
constructed in 1977. While it has never been repaved, it is in good shape and
still drains effectively.
In a study of a porous pavement system constructed at the Centre
County/Pennsylvania State Visitor center, researchers found that the system
had maintained a consistent infiltration rate. During a 25-year precipitation
event, there was no surface discharge from the stone beds.
Stabilizing Course or “Choker
Course : An optional stabilizing
course or "choker course"
consisting of clean single-sized
crushed stone smaller than the
bed's larger stone. That stabilizes
the surface for the paving
equipment.
Open Graded Asphalt Pavement
: An open-graded asphalt surface
with inter-connected voids that
allow storm water to flow through
the pavement into the stone
recharge bed.
Unpaved Stone Edge: A back up
system in case the pavement
surface should ever become
sealed, storm water flow off
pavement surface to stone edge
and into stone recharge bed
Porous asphalt roads : Cross Sectional Details
A details of section of porous asphalt bed is given below which comprises of
different layers of different materials and sizes as described below,
Un Compacted Subgrade :An un-compacted subgrade to maximize the
infiltration rate of the soil.
Geo textile fabric :A geotextile fabric that allows water to pass through, but
prevents the migration of fine material from the subgrade into the stone recharge
bed.
Stone Recharge Bed: A stone recharge bed consisting of clean single-sized
crushed large stone with about 40 per cent voids. The stone chamber serves as a
structural layer and temporarily stores storm water as it infiltrates into the soil
below.
Fig.1.7.2:
Shows Cross
Section of
POROUS
Asphalt surface.

9. 9
Do these pavements look “different?” Are they smooth?
While slightly coarser than standard asphalt, porous asphalt pavements are
attractive and acceptable. The surface of a porous asphalt pavement is
smooth enough.
What special additives or construction techniques are needed?
An added advantage to porous asphalt is that it does not necessitate
proprietary ingredients. It does not require the contractor to have special
paving equipment or skills. With the proper information, most asphalt
plants can easily prepare the mix and general paving contractors can install
it.
How does porous asphalt affect water quality?
There has been limited sampling data on the porous pavement systems,
although the available data indicate a very high removal rate for total
suspended solids, metals, and oil and grease.
Are there other environmental benefits?
Because of the open structure of the pavement, porous asphalt offers a
“cooler” pavement choice. By replenishing water tables and aquifers rather
than forcing rainfall into storm sewers, porous asphalt also helps to reduce
demands on storm sewer.
References
Self-Healing Technology for Asphalt
Pavements,
Amir Tabakovic´ and Erik Schlangen
Optimizing the highway lifetime by improving self
healing capacity of asphalt, 2012, Ali azhar, Niki
kringos.
Self Healing Asphalt - Extending the service life
by induction heating of asphalt, Gerbert van
Bochov
Induction heating of asphalt mastic for crack
control. Construction and Building Materials,
Liu, Q., Wu, S & Schlangen,
Fig.1.9.1:
Sample of Porous
Asphalt surface
with 100%
permeability
Fig.1.8.1:
Shows Porous
Asphalt surface
Absorbing 300
Gallons of water
in four Minutes