30 years of fundamental difference between UHPC and concrete

This photo is more than 30 years old. It is from the first flyer I used to sell UHPC. The photo was meant to explain to our customers what the general difference between concrete and UHPC is, because almost all of our customers at that time had no idea what the difference between concrete and UHPC is. At the time, I found this photo comparison brilliantly simple and clear.

Today, after 30 years, our team still has the feeling that many write and talk about UHPC but really do not recognise the basic difference. On the contrary, people today try to dilute and obfuscate the difference between concrete and UHPC. For these professionals, everything and nothing is concrete and UHPC. There are very few professionals who can explain the difference in simple and logical language. However, the architect, the structural engineer or the construction company must know the difference in order to be able to use both materials optimally.
For this reason we have decided to bring out this very old photo and to try again to explain the difference between concrete and UHPC and hope that some interested people out there will follow us, to whom we would like to thank already now.

The idea behind this photo was to produce two test cylinders and subject them to a pressure test. The main point was not to find out which material has the higher compressive strength, that was clear from the beginning.
No, we wanted to show and compare the fracture surface. This fracture surface shows the difference so simply and clearly.
At the beginning we mixed a standard cement binder and a UHPC binder and added the same grading curve and material quality to aggregates, filled them into test cylinders and waited 28 days. After 28 days, the concrete and UHPC cylinders were demoulded and pressed in a press until they broke. The result of this fracture can be seen in this photo.

The left cylinder is the standard concrete cylinder and the right cylinder is the UHPC cylinder.
Looking at the left cylinder, the fracture surface is clearly in the binder, the gravel aggregate is not broken. The weak point in this case is the cement binder.
If we look at the right cylinder, the fracture has gone through the gravel aggregate and the UHPC binder simultaneously and evenly. There is no weak point here. The UHPC binder is just as hard and resistant as the aggregate and the adhesion between aggregate and binder is extremely high.

This photo comparison and the resulting result shows that there are two fundamentally different binder systems, the concrete binder and the UHPC binder, whereas the UHPC binder is superior to the concrete binder by several times. This is how it was then, how it is now and how it will be in the future.

WPE DK International

Phone: 0049 176 601 73146
E-mail: ber@wpe-dk.dk
Homepage: www.wpe-dk.com

UHPC Desert sand binder - Local Concrete for Africa

Almost four years ago we developed a UHPC Desert cement binder to process desert sand into a concrete with very high strength values. Only cement binders, water and desert sand are necessary for this. For mixing a standard concrete mixer is needed. The focus of binder development two years ago was on the professional construction industry.

In discussions with architects and organizations operating in Africa we were asked, if we could develop a simple, not so high-quality version of this binder that can support the traditional simple
constructions of the rural population. After some
discussion, a list of requirements for this new
binder was created with which we now work in
our lab. UHPC binders were originally developed
with the aim of achieving an extremely high level
of strength. Then we discovered with our UHPC
binder the incredible combination possibilities
with a variety of natural materials.


Our UHPC binders can perfectly support or
replace wood, straw, loam and clay constructions in terms of their strength and resistance to high
UHPC can also be easily combined with recycled material. It can be made of furniture and sanitary equipment. UHPC concrete is not flammable, which contributes to the safety of the accommodation.

The aim of our current binder development is to
drastically reduce binder costs, to keep the
mixing procedure as simple as possible, to
drastically reduce the proportion of binder in the
overall mix, to reduce possible material transports,
to enable new material combinations with local
raw materials and to preserve as many
properties of UHPC as possible, temperatures and high solar radiation. UHPC binders are completely waterproof, even in very thin layers, do not rot and provide safe protection against termites.

There is also the possibility to use local cement for the production of UHPC Desert Sand Binder in addition to the local desert sand. For this we would have to test local cements for their suitability for our UHPC binder.

A difference in the definition of UHPC is always a difference in quality

The American Federal Highway Administration (FHWA) defines UHPC as follows:

UHPC is a fiber reinforced, portland cement based product. Through the appropriate combination of advantagements in superplasticizers, dry constituent gradiation, fibre reinforcments and supplemental cementitious materials.

UHPC is a cementitious composite material composed of an optimized gradation of granular constituents, a water-to-cementitious materials 
ratio less than 0,20 and a high percentage of discontinuous internal fiber reinforcement.

The mechanical properties of UHPC include  compressive strength greater than 150 MPa and a flexural strength geater than 15 MPa.

We define our UHPC grades as Ultra High Performance Concrete but without steel fiber reinforcement.
For all our UHPC grades, whether cast, mortar or spray, we achieve the technical values without the addition of any fibers.

UHPC is a cementitious composite material composed of an optimized gradation of granular constituents, a water-to-cementitious materials ratio less than 0,20 and no procentage of internal fiber reinforcement.

 

The mechanical properties (without fiber reinforcement) of UHPC include minimum compressive strength of 150 MPa (up to 260 MPa and more) and a minimum tensile strength 15 MPa (up to 30 MPa and more). We achieve 70% of the maximum nominal strengths less than48 hours and not 28 days.

Of course, fibers of all possible qualities and geometries, steel reinforcements and a wide
variety of aggregates can be added to the UHPC concrete. On our website you will find a long list of
these materials that we have been using for over 20 years. But if we want to compare material with
material fairly, we have to compare the base with each other and that means the pure UHPC binder without fibers and reinforcements.

A difference in the definition of UHPC is always a difference in quality.

                     Our HPC and UHPC compressive strength standard

UHPC for fire-safe escape routes and rescue rooms

With UHPC (Ultra High Performance Concrete),
escape routes in hospitals, public buildings, hotels,
shopping mall, restaurants, office towers, stairways,
elevator shafts and production facilities can be
designed safely and fireprotected.

Today escape routes in all areas can be designed
safely and in a modern design with UHPC materials.
Even the interior (fire resitant furniture) in escape
areas can be elegantly and filigree made of UHPC.

Our standard UHPC concretes achieve compressive

strength of up to max. 210 MPa / 30500 psi and a
flexural strength up to max. 27 MPa / 3900 psi. We
produce UHPC materials as mortar, castable and
shotcrete.

The UHPC material grades can easily withstand
continuous temperatures up to 450°C / 842°F without
loss of strength. The high temperature resistant UHPC
can withstand continuous temperatures up to
1200°C / 2190°F with only a very small loss of strength.
Our UHPC materials are extremely temperature shock
resistant and impermeable to water, so that the damage
caused by extinguishing water is very low.

It is also possible for us to combine UHPC materials
with extremely effective thin layer insulating
materials so that even existing concrete or steel
structures are permanently protected against heat and
that at very low wall thicknesses and material weights.

Comparison of UHPC and concrete during processing to precast concrete elements

The first UHPC Ultra High Performance Binder
was developed more than 30 years ago. Since
then they have been continuously developed.
The UHPC binders have been improved or new
ones have been developed and produced in
accordance with the requirements due to their
experience in a wide variety of application areas
and industries worldwide. From the beginning,
our UHPC binders were produced as mortar,
castable and shotcrete.

UHPC castables are inexplicably used to a much
lesser extent in the production of precast concrete
than standard concrete. These UHPC materials
could offer enormous advantages for manufacturing
as well as in the use of precast concrete parts.
Here are some applications and their advantages
compared to standard concrete:

 - Light weight of the UHPC elements. Due to the
    extremely high strength, smaller component cross
    sections can be selected, which leads to lower
    individual weights.
 - More elements can be loaded per truck, which leads

   to fewer loads.
 - Due to the lower individual weights, lower crane
    capacities are required.
 - The raw material requirement is drastically reduced
    due to the smaller component cross-section.
 - UHPC materials develop high strength values ​​in a
    short time. Our UHPC materials reach 70% of their
    nominal strength after 48 hours.
 - Shorter production times per element, higher cycle
    times - higher quantities per unit of time compared
    to standard concrete - lower unit costs.
 - Shorter delivery times.

UHPC binders are based on nanotechnology and 
are extremely fine.
Advantage:
It is possible to produce much more precise shapes.
Joints, edges do not require reworking. The more
precise the mold, the more precise the UHPC
element.
UHPC concretes do not form pores and are usually
self-compacting. This means that surface structures
can be achieved that cannot be achieved with standard concrete.

UHPC concrete is extremely resistant to most 
environmental influences
Advantage:
UHPC concretes are extremely resistant to
corrosion, de-icing salt and frost, which leads to a
much longer life expectancy than standard concrete
UHPC many times exceeds concrete, marble,
limestone, sandstone and many other natural stones.


www.hhbc-consulting.de
info@hhbc-consulting.de

Protection of river banks and bridges with UHPC technology

At a meeting of local councils in the alpine

region, hhbc-consulting and WPE DK were

invited as guests to discuss possible

rehabilitation and protection of river banks

and bridges. Due to climate change, especially 

in the mountainous regions, the streams and 

rivers are flooded with enormous amounts 

of water as a result of enormous amounts of 

rain and continuous snow melt. In addition 

to the water flowing at high speed, ever 

greater quantities of debris are also being 

transported. Water and debris are increasingly 

damaging bank and bridge structures. For the 

most part, they are not designed for these 

quantities.

One of the main points of this discussion,
was the rehabilitation of the massive damage
caused by scree and water masses on the
construction of the riverbanks, especially in
areas of river diversion and river guidance
in villages and towns.

Particularly the rising water masses among
other things by massive lasting rains and
resulting high flow velocities with scree
movements give rise to concern.

As one of the possible solutions for the future,
the use of UHPC Ultra High Performance
Concrete as a refurbishment material and as
construction material for renewed protective
installation was discussed.

UHPC concrete would offer concrete with its
extreme strength (over 140 MPa - 240 MPa),
very high wear resistance and extremely high
corrosion resistance.

In addition, a joint-free processing is possible.

Due to these characteristics, the design of river

banks and river diversions with artificial rock

constructions made of UHPC was discussed.

As assembly methods for UHPC, assembly

pre-fabricated elements, casting or spray-on-site

(Shotcrete) assembly was discussed.

Since UHPC develop within 48 hours 70% of its

nominal strength are very fast in assembly methods

and thus the repair time is very short.

Due to the many years of experience we have in
offshore and coastal areas, first projects have
been agreed.

Precast elements and Tilt-up manufacturing with HPC and UHPC concrete

HPC and UHPC concrete are very suitable for processing on the construction site in the Tilt-up system or in precast concrete plant. Residential housing and industrial buildings of all sizes can be manufactured using these two systems.

HPC and UHPC concrete has a long list of advantages over standard concrete

- High tensile strength- Extremely high compressive strength
- Very fast strength development
- UHPC elements have a very high production accuracy. If the mold is   exact, the element is exact.
- High chemical resistant
- Absolute corrosion resistant
- Even small layers already lead to an absolute waterproofness.

- Customer requirements such as burglary resistant, fire resistant, storm resistant and acoustic properties as well as noise reduction can be easily met.
- Combinations with a high-performance insulation layer reduce energy costs by several times compared to wooden houses or brick houses.
- The required wall thicknesses are only a fraction of comparable housing designs.

Tilt-up elements
Tilt-up elements are manufactured using locally produced molds and concrete in a wide variety
of HPC and UHPC concretes produced by us achieve 70% of their nominal strength in just 48 hours, the average nominal strength of our UHPC concretes is 140 MPa / 20000 psi.

Due to the compessive and flexuaral strength, it is possible to work with considerably smaller wall thicknesses, which leads to substantial material reductions and costs.
The extremely fast development of strength leads to faster assembly, the overall completion time is significantly reduced, which can also lead to cost reduction.

Precast elements
Prefabricated systems have been used in Europe for more than 50 years. There is a huge amount of standard residential house design variations from small houses, garages, workshops to entire building

complexes. Architects design exceptional prefabricated houses according to customer requirements. The elements are already manufactured and prepared weeks in advance in a precast plant, so that only a few days are needed on the construction site for a complete completion.
The advantage is the very small footprint on site.
The elements come with trucks in the correct assembly order on the construction site. A crane positions the elements and very few fitters are needed for assembly. It can be installed all year round, regardless of the weather contitions.

UHPC concrete for precast production

UHPC concrete has many commercial as well as technical

advantages over standard concrete for the production of 

precast concrete elements.

More and more architects are specifying UHPC concrete 

as a standard material for their façade design. There are 

no design limits for façade constructions.
In recent years, we have developed UHPC binder systems 

that can be processed into lightweight concretes or 

insulating concretes, especially for façade construction.

- We produce UHPC materials with a strength of

   40 MPa to 240 MPa.
- Our UHPC materials reach 70% of their maximum

   nominal strength within 48 hours. Faster strength

   developments are possible on customer request.
- We only need sand, not gravel, to process UHPC

   concrete.
- With our UHPC Desert Sand Binder, desert sand

   can also be processed without any problems.
- All of our UHPC materials are self-compacting

   and need no or very little vibration.
- Our UHPC materials have extremely little to no pore

   development.
- The nanotechnology development of our UHPC

   binders enables extremely fine surface structures to

   be created.
- With the use of fibre reinforcement it is possible

   to create very thin structures of high strength.

- For prestressed elements, the pre-tensioning force
   of UHPC material can be chosen to be much higher
   due to their very high strength than standard concrete.

- Very good flow properties for casting complicated

   geometry and filigree surface structures.

Processing of UHPC binders
Only a shaft or pan pot mixer is required for

processing.
The UHPC binder is mixed with sand or desert

sand and a very small amount of water.
It is not necessary to add additives.

Applications

• Double walls 
• Pre stressed elements 
• Tubes
• Bridgedeck elements
• Stairs
• Piles
• Supports
• Tunnel segments
  
• Facade elements
  
• Balconies
• Sea defence units
  
• Floor tiles in large geometries                
  
• Security
  
• Vertical garden (facade) elements
• Sewage pipes and box culverts
• Floating elements
  

UHPC Workshop in Germany

Our manufactory is not very big. Here we
playfully develop new design ideas, new
material combinations and, if necessary,
develop new UHPC Ultra High Performance
concrete mixing recipes.

Our manufactury is to transform the
advantages and peculiarities of our own
UHPC material creations into design
designs. We also develop special material creations for designers, similar to those in the textile industry.
Our UHPC material qualities are used from the smallest jewelery to complete house interiors.

We have the possibility for interested parties outside of Europe to connect directly to our UHPC development laboratory via TEAM, SKYPE etc.. After making an appointment, we will then be available for you.

We only produce UHPC design material of the highest quality for designers.

Some of our qualities can be processed
with standard mixing machines.

We are working on a new cast process
in order to be able to achieve even finer
wall thicknesses and structures, or to be
able to use previously used processing
techniques in the field of clay processing
and plastering for our material. We are
currently working on a material quality
that can be processed like clay on the
turntable.

We plan to move our manufacture
workshop this year in an old farm
with big barns.
Here, we want to invite students and
designer from all over the world to
work together with us to develop new
design ideas and put them to practical
use, which requires more space.


You want to try out our UHPC design
material?

We ship 5 kg plastic containers free of
charge within Europe.
Outside of Europe, unfortunately, we
have to take a very small freight surcharge.

WPE DK International

Phone: 0049 176 601 73146
E-mail: info@wpe-dk.dk
Homepage: www.wpe-dk.com

UHPC - Standard concrete comparison

Standard concrete
A mixture of cement binder + sand + gravel + water

UHPC concrete
A mixture of UHPC binder + sand + water

One of the most important quality parameters
when comparing standard concrete and UHPC

Standard Cement Binder                         UHPC Binder         

is water/cement ratio and compressive strength.

The water/cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix.
A lower ratio leads to higher strength and durability, water/cement ratios of 0.4 to 0.5
are more typically used for standard concrete qualities. For higher-strength concrete, ratios of 0.20 - 0.18 are used.

Despite the extremely low w/c value, UHPC materials of high production quality 

can be processed in much the same way as 

concrete.

Among other things, the low w/c value
means that the pore volume is extremely low
or even absent, which leads to very high
compressive strength (up to 240 MPa) and
very high corrosion resistance. UHPC is also
self compacting.

Another effect of the low pore volume in UHPC
is the extremely high content of wetted surface,
e.g. on steel reinforcements against concrete.
This leads to very strong connection of steel
and UHPC. If you wanted to pull a standard
reinforcing steel out of a UHPC block you
needed enormous tensile forces compared to
a standard concrete reinforcement.

Due to the extremely low pore volume and the

high pressure and tensile strength combined
with the exclusive use of sand as aggregate, the coverage of the reinforcement can be reduced. Likewise, the distance between the reinforcing bars could be reduced.

In this context, UHPC can be used to make
concrete structures that are closer to steel structures than the ones in their dimensions
and bearing capacities.

 

 

 

 

 

 

 

 

WPE DK International

Phone: 0049 176 601 73146
E-mail: info@wpe-dk.dk
Homepage: www.wpe-dk.com

 

UHPC - What do we understand by this and what does your customer mean?

Are you sure you do not compare oranges with bananas ????

Today's state

Today, there are a variety of so called UHPC Ultra High Performance Concrete products available on the international market.

Every concrete quality is described very precisely in the technical literature. There are well defined general material tests. Every architect and structural engineer can work with these defined values.

For more than 30 years we have been developing and producing UHPC for a variety of applications whether in architecture, offshore, security, road construction, bridge construction, tunnel construction etc.
In this long period of time, no one has succeeded in establishing a clear, worldwide definition of UHPC. It will probably never be possible.

An explanation attempt

Ultra High Strength Concrete was developed in 1981 with a compressive strength of more than 120 MPa /17500 psi. Since this newly developed binder has found a hitherto unprecedented range of possible applications, the term Ultra High Performance Concrete was developed. This generally used product designation is exclusively focused on the word performance and is therefore not a technical specification.

The word analysis

UHPC = Ultra High Performance Concrete

Ultra = Extreme, Special, Exceptional

High = Very intense, Powerful, Strong

Performance = Performance, Exercise, the act of performing, presentation, to carry out an action

Concrete = Formed of concrete, a compact mass of sand, gravel, cement and water

Elvis, Michael Schumacher, Michael Jordan, Neil Amstrong, a 747 Jumbo Jet, a Rolls Royce had an Ultra High Performance, but did they perform in the same way? No, you cannot compare them.

The original idea of an Ultra High Strength Concrete with a minimum compressive strength of 120 MPa / 17500 psi plays no decisive role in this performance.

The most important characteristics of the Ultra High Performance Concrete are made by a

special cementitious added with mineral, metallic, organic, non-metals, inorganic non-metallic additives or aggregates. The water/cement ratio should be below 0,20.

The next generation of UHPC materials has already been developed and is being processed - UHPC desert sand concrete. It will no longer be necessary for some countries to destroy their rivers and beaches or to transport sand around half the planet.

We are working on a product specification that allows every customer to ensure that they get the highest quality UHPC Ultra High Performance Concrete.

 

 

 

WPE DK International

Phone: 0049 176 601 73146
E-mail: info@wpe-dk.dk
Homepage: www.wpe-dk.com