The American University In Cairo
School Of Science And Engineering
Department Of Construction and Architectural
Presented to: Dr. Mohamed Nagib Abou-Zeid
What is Carbocrete?
History of carbon fibers
Manufacturing of carbon fibers
Carbon fibers in construction
Carbon fibers vs. steel (Properties)
Key properties of Carbocrete
Advantages & disadvantages
It is a type of concrete that is reinforced with carbon fibers so it’s also
known as “Carbon Reinforced Concrete”.
It is a new highly stressable lightweight composite construction that
combines special fine grain ultra high-strength concrete and carbon fibers.
It has higher strength than steel with quarter of its weight.
In late 1800s, Thomas Edison was the first to use carbon fibers as filaments
for early light bulbs.
It lacked the high tensile strength of today’s carbon fibers; however he
used it because of their high tolerance to heat which made these fibers ideal
for conducting electricity.
It wasn’t until the late 1950 that high-performance carbon fibers was
manufactured by Mitsubishi Rayon
The USA’s Air Force and NASA didn’t wait develop the carbon fiber
technology and began to use carbon fiber reinforced polymers to replace
heavy metals to allow aircrafts to be lighter and faster.
Carbon fiber aircraft propeller
Raw carbon fiber is made from either polyacrylonitrile (PAN)
or petroleum coal.
These fossil-fuel- based materials come from either petroleum
refining or natural gas processing
1st: in the thermoset treatment, the fibers are stretched and heated to no more
than 400 C
2nd: in the carbonize treatment, the fibers are heated to about 800 C in an
oxygen free environment to remove non-carbon impurities.
3rd: fibers are graphitized; this step stretches the fibers between 50 to 100%
elongation, and heats them to temperatures ranging from 1100 C to 3000
C. The stretching ensures a preferred crystalline texture, which results in the
desired tensile strength.
4th: the last two treatment steps, surface treatment and epoxy sizing, are
preformed to enhance the carbon fiber bonding strength.
PAN Manufacturing Process
Carbon fibers are mostly used for repair purposes of old structural
element against shear and flexure failure; the material know as CFRP.
However, in the early 1990s, researches showed that carbon fibers can
be used inside the concrete instead of steel reinforcement showing a
significant improvement in the flexural and tensile strength of
Up to 75% lighter
5 times higher tensile strength
2 times higher stiffness
Higher temperature tolerance
Comparison of Fiber Strengths
Comparison Between Carbon
Fibers and Steel Fibers
High tensile strength:
High initial cost
Less running cost
Lack of knowledge:
Absence of codes
No implementations yet
Less materials needed for
maintenance and construction.
High thermal conductivity
High HVAC consumption
Easy to handle
Risk of lung cancer in the manufacturing
More creative architectural design
High abrasion resistance:
Suitable for highway construction
Low coefficient of thermal expansion
High fire resistance