Materials
science innovations continue to advance wonders that we can appreciate. Two of
them that may do so involve better asphalt. These are graphene-infused asphalt
and self-healing asphalt. Both have the potential to significantly reduce the
problem of potholes. These innovations are expected to make road maintenance
less labor-intensive, make road repairs more efficient, and increase road
safety. Roads have been an engineering marvel since ancient times. The Roman
roads, in particular, built of layers of limestone, concrete, mortar, and other
materials, are renowned for great construction innovations and exceptional
durability, with one accidental innovation that involved a kind of self-healing
mechanism. When I was an undergraduate, I took a History of Technology class
and did an oral presentation on Roman roads, and I found the research
fascinating.
As I know well from the road
I live on, freeze/thaw cycles where water enters potholes, freezes and expands,
and makes them bigger, can make potholes hard to avoid. They can damage
vehicles if not negotiated properly, leading to expensive replacement of shocks
or struts.
Graphene-Infused Asphalt
Graphene-infused asphalt has
superior strength and crack resistance. Lab tests of it show enhanced
load-bearing capacity and increased resistance to deformation.
According to Morning
Overview:
“Graphene’s unique properties, including its
conductivity and elasticity, allow asphalt to self-adjust to environmental
stresses, minimizing the formation of cracks. This technology could lead to
significant savings in long-term maintenance costs compared to conventional
asphalt. Recent studies have shown promising performance metrics, with
graphene-enhanced asphalt demonstrating superior durability and resilience.”
Graphene-modified thin
asphalt layer (GMTL) construction was presented in an Italian paper in the
journal Transportation Engineering in 2025. According to Steven Davies in
Sustainable Construction Review, who reviewed the paper, GTML offers both
restoration and improved mechanical properties:
“GMTL as a new intermediary layer between the binder and
wearing course of road pavements. This thin layer, infused with graphene, aims
to enhance the overall performance and longevity of the pavement structure.”
“Road agencies are constantly seeking ways to improve
pavement preservation techniques,” Maltinti explains.
“The GMTL offers a novel approach that not only restores
but also significantly enhances the mechanical properties of the pavement.”
“The GMTL demonstrated remarkable volumetric behavior,
with void values decreasing from 14.3% at 10 cycles to 4.6% at 230 cycles,
indicating excellent compaction and stability. Additionally, the mixture
exhibited good workability, making it practical for real-world applications.”
“Core samples with the GMTL showed a 33.2% increase in
indirect tensile strength and a 10% increase in indirect tensile stiffness
modulus. These improvements translate to a pavement that can withstand higher
loads and resist deformation more effectively.”
“One of the most striking findings was the GMTL’s
exceptional fatigue resistance. The fatigue curves indicated that the GMTL
could endure cyclic loads with minimal degradation, both in terms of stress and
deformation. This means that roads treated with GMTL could last longer and
require less frequent repairs, a significant advantage for both road agencies
and motorists.”
Potential benefits of the
technology include more durable, cheaper road maintenance and construction, and
fewer traffic disruptions due to less needed maintenance.
Other studies in the U.K. and
in Colorado have validated the benefits of graphene-infused asphalt. It is now
expected to be deployed more globally.
High cost and limited
availability have led to slow adoption of graphene as a road material, but that
is changing. GrapheneSupplier.com notes:
“New advancements in on-site, in-house graphene
production technology now make high-quality, bulk graphene both accessible and
affordable at industrial scale.”
Self-Healing Roman Roads
Incidentally, one mechanism
responsible for the success of Roman Roads is now thought to be an innovation
that inadvertently led to self-healing of cracks in the road materials, which
were not asphalt, but mostly limestone. The main mechanism for Roman road
durability and self-healing is thought to be the Roman concrete, which utilized
a process known as hot mixing. The materials used in the recipe included
quicklime (calcium oxide), derived from heating high-purity limestone, and
volcanic ash. Adding water to the mix results in quicklime being involved in an
exothermic (heat-producing) chemical reaction. However, not all of the calcium
oxide is used. Some remains in the form of clasts, or perhaps “clumps” in the
mix, that did not react with the water. If cracks form and bring water through
them to the clasts, they can then react and act to heal those cracks as they
harden in the open spaces.
Self-Healing Asphalt Via Plant Spores and Oils
New research in the U.K. utilized
biomass waste and AI to develop a self-healing asphalt, with lab tests
revealing stellar self-healing capabilities.
“We are proud to be advancing the development of
self-healing asphalt using biomass waste and artificial intelligence. This
approach positions our research at the forefront of sustainable infrastructure
innovation, contributing to the development of net-zero roads with enhanced
durability,” said Jose Norambuena-Contreras, a Senior Lecturer in the
Department of Civil Engineering at Swansea University.
Interesting Engineering
summarized the research well, and below explains the problem of asphalt
deterioration via bitumen oxidation.
“The fundamental cause of asphalt deterioration, leading
to the formation of cracks, lies within the behavior of bitumen. It is a
viscous binding agent that holds the asphalt mixture together.”
“Over time, bitumen undergoes a process of oxidation,
causing it to harden and lose its flexibility. But the researchers highlight
that the exact processes that contribute to this hardening remain elusive.”
“The team has successfully devised a method to not only
halt the progression of these cracks but also to effectively reverse the damage.”
Microscopic, plant-derived
spores filled with recycled oils were added to the asphalt. When a crack
appears, the spores are carried by the oil into the void spaces. Lab test
revealed that small surface cracks in asphalt can be healed by this formula
within an hour of forming. In a way, this is akin to biological healing of
tissue such as skin. Various bio-cement formulas are being explored for various
uses, including for plugging wells in the oil and gas industry. Much like
graphene-infused asphalt, self-healing asphalt promises to extend the
durability and lifespans of roads as well as significantly reduce maintenance
requirements. The U.K. researchers also touted their use of sustainable
materials, such as biomass waste.
“We are also using sustainable materials in our new
asphalt, including biomass waste. This will reduce our dependence on petroleum
and natural resources. Biomass waste is available locally and everywhere, and
it is cheap. Producing infrastructure materials from local resources like waste
reduces the dependence on petroleum availability, which helps those areas of
the world that have limited access to petroleum-based asphalt,” said
Martin-Martinez in the press release.
Self-Healing Asphalt Via Induction Heating, Steel Fibers.
Microcapsules, and Rejuvenators
Another type of self-healing
asphalt depends on steel fibers (such as steel wool), microcapsules, and
rejuvenators to promote self-healing properties. An article in Streetworks
notes the work of Dr. Erik Schlangen:
“Dr. Erik Schlangen of Delft University of Technology
pioneered a version of self-healing asphalt containing steel fibers, which
respond to induction heating by creating a chemical reaction that softens the
asphalt, enabling it to close cracks. Other approaches involve microcapsules
filled with rejuvenators that break open when cracks form, releasing agents
that restore flexibility and seal the asphalt.”
It is estimated that
self-healing asphalt could reduce road maintenance by about 30%, which is
significant, and could be quite cost-effective over time, recovering the
initial high costs followed by the benefits of longer maintenance intervals.
Road repairs can be hazardous, costly, disruptive, and use up resources. All
this can be reduced.
However, there are
significant challenges to overcome with all methods of self-healing asphalt.
The high initial costs will limit the rollout. The lack of long-term studies
due to the newness of the technology means that uncertainties about it
long-term durability under different stress conditions will remain a concern,
at least for a while. Integrating it with existing infrastructure may also be a
considerable challenge. Another challenge will be recycling the steel fibers
and rejuvenating capsules, which would disrupt the current recycling of road
materials. Once these problems are overcome, the technology should be able to
be more widely deployed. Right now, there are just pilot projects,
“In the Netherlands, Dr. Schlangen’s research team has
launched several pilot programs using induction-heating self-healing asphalt on
rural roads, where lower traffic volumes allow for focused testing. These
projects aim to assess the long-term viability of self-healing materials and to
gather data on their performance in real-world conditions.”
Dr.
Schlangen’s method also incorporates porous pavement material that allows water
to drain through the surfaces, running to the side of the road or routed into
collection devices. Porous pavement is also being used more and more for
diverting urban stormwater. The porous pavement also allows water to run
through rather than collecting on the road. He notes that it is quieter as
well, reducing road noise. The research suggests that road maintenance can be
cut in half from every two years to every four years, saving money.
References:
New
asphalt tech could finally end potholes. Alexander Clark. Morning Overview.
November 11, 2025. New asphalt tech could finally end
potholes
Graphene-Infused
Asphalt Revolutionizes Road Pavement Durability. Steven Davies. Sustainabe
Construction Review. July 14, 2025. Graphene-Infused Asphalt
Revolutionizes Road Pavement Durability - Sustainable Construction Review
Graphene
Asphalt: Transforming Asphalt Performance Nationwide. GRAPHENE ASPHALT
New
Self-Healing Pavement Technology. American Society of Civil Engineers. Self Healing Asphalt - ASCE Grand
Challenge
Self-healing
asphalt uses plant spores to stop potholes before they start: It’s a step
towards smarter, more sustainable, and pothole-free roads. Mrigakshi Dixit.
Interesting Engineering. February 27, 2025. 1-hour repair: New asphalt tech
prevents potholes before they start
Self-Healing
Asphalt: What It Means for the Paving Industry. Street Works. November 6, 2024.
Self-Healing Asphalt: What It Means
for the Paving Industry
A
2,000-year-old building site reveals the raw ingredients for ancient Roman
self-healing concrete. Ray Laurence. The Conversation. December 9, 2025.
A
2,000-year-old building site reveals the raw ingredients for ancient Roman
self-healing concrete
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