UHPC Earthquake security systems for existing buildings

Ultra High Performance Concrete (UHPC) is a high-strength, ductile material formulated by combining cement, microsilica, fine sand, water, and steel or ceramic fibers and mesh.

The UHPC concrete provides compressive strengths up to 250 MPa / 36200 psi and flexural strengths up to 30 MPa / 4300 psi.

The ductile behavior of UHPC is, with the capacity to deform and support flexural and tensile loads, even after initial cracking. 

 

Façade elements made by UHPC, protect people and vehicles in an earthquake against fragments litter in building structures made 
of concrete and brickwork.

Concrete ceilings are rigid and brittle structures that at the an earthquake stress the concrete structure can break partially. The fracture is not 
a slow phenomenon under load - the fracture occurs when overloading on suddenly.

The result is that to loosen individual fragments of the ceiling could (fragments litter) fall on machines or people. Are the fragments large enough, it can lead to complete component failure.

UHPC prefabricated ceiling structures prevent like a prestressed network the fragments become loose during the quake from the ceiling.

People and machines are protected by such a suspended ceiling construction.

Emergency exits can win with such additional structure several times of safety.

Just as concrete ceilings and concrete columns are complex constructions an essential safety feature of a quake. The concrete columns must take tremendous 
flexural and compressive forces. A chipping of the concrete structure of the inner steel reinforcement would have a very rapid component failure result.

Concrete columns can by a jacket (by shedding) of UHPC gain much stability and carrying capacity. A chipping of the concrete structure at a load by an earthquake of small and medium thickness is almost impossible with the appropriate cover. 

Advantages of UHPC

• Extreme high compressive strength
• High flexural strength
• Extreme low porosity
• Extreme good flowability
• Fast increase of compressive strength (min. 70% after 48 hours)
• High wear and impact resistance
• Absolute frost and thaw resistance
• Impermeable to fluids but still vapour permeable
• Anticorrosive features
• Good bonding to sub-bases, aggregates and reinforcement
• High temperature resistant
• Jointless lining
• Usable as mortar, grout and spray
• High ductility in combination with fibres or nano fibres
• Usable with standard concrete tools
  
  

UHPC - His entry before and after a quake

UHPC materials can be used as additional safety in new concrete structures such as buildings, bridges, etc. For existing buildings and very old buildings, targeted activities involving the use of UHPC materials can significantly increase the safety of people and buildings. With UHPC materials, damaged buildings can be repaired to restore their old stability or improve their stability against earthquake loads by improving their building structure.

Possible applications for high quality UHPC materials

Repairing

To make existing structures safer for future earthquake

Retrofitting

To upgrade the earthquake resistance up to a level of  the present day codes by appropriate techniques

Strengthening

To upgrade the seismic resistance of the a damage building

Rehabilitation

Reconstruction or renewal of a damaged building to provide the same level of function, which the building had prior to the damage

Restauration

Rehabilitation of buildings in a certain area

Remoulding

Reconstruction or renewal of any part of an existing building owning to change of usage or occupancy

Example of retrofitting techniques

• Minor cracks
  Repair by injecting UHPC
• Buckled longitudinal reinforcement, broken ties and crushed concrete
  Replacement of new reinforcement welded with existing bars and new additionally closed ties were placed, UHPC concrete with low shrinkage properties installed.
• Severely damaged columns adjacent to added walls
  Retrofitting with encasing in UHPC concrete with appropriate longitudinal and transfers reinforcement.
• Other columns
  Retrofitted with wire mesh and cover with 50 mm UHPC concrete by spraying or casting
• Existing masonry walls
  Are retrofitting by using wire mesh and 30 mm of UHPC® mortar or spray

Like concrete cover constructions, concrete columns are also essential safety aspect in a quake. The supports have enormous bending and compression forces to take. 
A spalling of the concrete structure from the internal steel reinforcement would have a very fast component failure result.

As with the concrete floors, columns can be replaced by a grouting UHPC gain significantly in stability and carrying capacity. A flaking of the concrete construction is under load from a quake of small and medium strength with 
appropriate sheath almost impossible.

In a quake will be in the brickwork of a building very quickly showing cracks in the in the worst case, individual stones break loose (Rubble throw) or a whole bandage, which too can lead to a component failure. The cracks in the masonry after a quake are permanent and can become one uninhabitability and demolition of 
the building to lead.

Damaged masonry will be repaired differently depending on the degree of damage.

Fine cracks can be filled with UHPC injection methods. Loose masonry, bad mortar can be increased by new masonry and UHPC mortar substantially in the strength and bending tensile strength. Masonry can also be improved in its entire surface with a fibre reinforced UHPC layer in combination with steel or fibreglass reinforcement substantially in its static structure. Especially glass fibre or carbon fibre reinforced 
UHPC show a high ductility.

In any case, should structural modifications such as those described here, be agreed in consultation with 
an architect, stress analysts and the competent local planning authority.

UHPC Ultra High Performance Concrete in local Asian architecture

UHPC Ultra High Performance Concrete is barely considered in modern Asian architecture, although this material is over 25 years old. 

HPC and UHPC concrete is not just a concrete, it is something special. In the beginning, 25 years ago, we broke one strength record after another. We have done extreme constructions and linings and cold and heat.
For the last 15 years, we have been focusing on sustainability in the Asian market with our HPC and UHPC materials, using local materials. We can perfectly combine our materials with local construction materials such as bamboo. The result is a unique, sustainable, cost effective material or construction. With our HPC and UHPC binder systems, we can incorporate almost any local material. We can work with local architects and contractors to create buildings and structures that can withstand floods, fires, storms, earthquakes and insect attacks. We also want to learn with local

builders how we can work together to create permanent floating platforms for living on the water or on the coast.

 

Yet this extraordinary material offers a large number of answers to the requirements of modern Asian architecture.

Corrosion
HPC/UHPC materials are very good corrosion resistant. Old concrete, wood or steel structures can be easily and inexpensively repaired and made usable for many decades.

Waterproof
HPC/UHPC materials are waterproof from a layer thickness of 10 mm. Houses can be made resistant to

flooding so that they can be quickly cleaned and used again after a flood.

Seawater
UHPC materials are absolutely seawater resistant. HPC/UHPC can be processed underwater. This means that jetties can be repaired easily and quickly. they can then be used again for the next 50 years.

Rotting
UHPC do not rot. Wooden structures that are already starting to rot or are damaged can be quickly and permanently repaired with HPC/UHPC.

Material Strength

HPC/UHPC materials reach strengths from 20 MPa to 240 MPa

Steel structures
HPC/UHPC materials can permanently replace steel structures and require no maintenance

Earthquake
HPC/UHPC materials offer solutions to increase the seismic safety of existing buildings

Temperatures
HPC/UHPC materials are extremely temperature resistant from -90° to +1200°C. An ideal material for facades

Design
With HPC/UHPC materials it is possible to achieve extremely fine surface structures

Processing
HPC/UHPC can usually be processed like standard concrete. We produce HPC and UHPC castable,

mortar and shotcrete versions.
HPC and UHPC materials help to drastically reduce the concrete requirement / weight.
HPC and UHPC sheathing of steel or wooden structures standing on or in the water, will permanently protect the construction against rotting.
Of course, UHPC can also be used to repair buildings and floors easily, quickly and effectively.

There are many other arguments for the use of UHPC in Asian architecture.
We are happy to be of service to every designer, architectand contractor with our decades of experience.

At the moment we are producing our HPC and UHPC materials in Europe. However, we plan to build one or two production locations in Asia in the near future.

 

WPE DK International

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

 

HPC Leight weigth and standard products systems for architecture, civil construction and design

In addition to our UHPC offshore, industrial
flooring, wear protection, security product
systems, we will produce HPC product
systems for architecture, civil construction.

These products will not have the extreme strength
values ​​like the UHPC industrial qualities but have
all the characteristic properties of a high quality
UHPC, such as verygood corrosion resistance,
high early strength development, very good flowability etc.

The new HPC product qualities are:
HPC Leicht 25   Compressive strength 20 - 25 MPa (Lightweight)
HPC Leicht 35   Compressive strength 20 - 35 MPa (Lightweight)
HPC 45              Compressive strength 45 - 50 MPa
HPC 85              Compressive strength 80 - 85 MPa
HPC 135            Compressive strength 130 - 135 MPa

We will offer these HPC qualities in various
packaging sizes, most likely from 25 kg paperbag
to 1 to big bags. We will produce these HPC
products as mortar, castable and shotcrete or as
interieur or exterior plaster.

We can offer private customers as well as
industrial customers all UHPC qualities as
pure binder material or as a mixed material
binder + aggregate.

 

WPE DK International

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

Recycling of old building materials with HPc and UHPC bindersystems

In our fast-moving times, old houses, some of
them historical houses, are being brutally torn
down to make room for new, more modern,
larger, higher and often not more beautiful but
more effective new building designs. Very
often there is no time left and there is often no
will to secure the valuable and reusable old
building material.

The end of an old building is a heap of rubble
that is only suitable as gravel material for the
subbase material of streets.

The architects in particular could campaign
for the reuse of such materials. It would be
entirely possible to reuse these old materials
in modern design concepts and to save some
valuable raw materials.

This year we will start some attempts to
combine UHPC with a variety of old used
materials. We are very sure that this is
possible without any problems, both in terms
of statics and construction. Of course, with
UHPC we can copy old materials in
appearance and design extremely precisely,
in some cases this is certainly sensible and
necessary. However, we want to reuse old
materials and hand them over to a new
design function. Even building rubble could
become a very interesting concrete material

in combination with UHPC. We also want
to give architects and designers new design
options using old and ultra-modern materials.

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

UHPC 3D printing

It is interesting to see today what printing results universities and printer manufacturers achieve.

The results are an interplay between printer technology and material technology. In my opinion today, very good results are achieved in the design areas with the printers, but many problems still have to be solved in professional architectural building construction.

There are

Compressive strength

The standard concrete reaches its maximum compressive strength after 28 days. For the printing technology unacceptable, here must be helped with accelerator. Printing speed and strength development must be matched and optimized without loss of strength.
UHPC Ultra High Performance Concrete can be a solution. Strengths of over 200 MPa can be achieved here. Already during the UHPC binder production, we can adjust the strength development, as well as the flow characteristic. The addition of commercially available additives is no longer necessary.

Print speed

Of course you want an optimum speed, you want to process a large amount / weight of concrete in a very short time. The concrete should be able to support itself after a very short time and be load-bearing for ceiling elements.
With UHPC materials, large amounts of material are already processed in a short time using the wet and dry spraying process. The consistency of the UHPC print material can be adapted to the printer characteristic. UHPC materials already develop high strength values in short time in the standard qualities. However, this time can be extremely reduced by changing material production.

Statics

The print heads are usually small in diameter and the applied wall thicknesses compared to a masonry or a finished concrete wall are very thin. Static load-bearing walls can be printed for several floors, or double-skin walls must be printed in order to achieve a structurally stable construction. Do I have to print double-shelled?

Heat / cold insulation

If I print with a standard concrete I do not achieve any insulating properties. So I have to print double-shelled and fill the cavity with insulation material or retrofit an insulating layer from the inside.
At the moment we are the only ones who are able to combine a high pressure resistant material with an insulating material. This combination material is also pumpable.

Steel girders, reinforcements

Even with 3D printing, you can not ignore reinforcements and support structures, or you can remain eternally restricted to small, simple and low-rise building constructions. How can I optimally combine carrier structures, steel reinforcements with a single printing process?

Last but not least interesting design

So far I have seen the obligatory pressure bulges on all prints. For the beginning, this may be fine but soon you should have printing technologies that ensures a sharp-edged pressure even on the wall corners. A rework of the walls in the flat areas to get is cost and time consuming. Of course, when I use the printing technology, I also want to print exceptional geometry and thin-walled constructions.

I have a note at the end

If all my misgivings can be wiped out the question remains if I want to print a large building, I need a fairly large printer technology which is not even built and dismantled and I need a very fast continuous flow of material to the printer when the printer should work quickly.

I do not want to know misunderstood. I think 3D printer technology is very interesting for the future and I know that some engineering companies are working on technical solutions. As part of our material development, we also work on a flexible, extreme fast-curing, high-compressive strength material for the printer producer. In close technical agreement with the respective printer manufacturer, we can adapt our UHPC materials to the requirements and provide test material to the printer manufacturer.

UHPC HT and concrete under heavy fire

Again and again we hear of skyscrapers or facade
fires. In the rarest cases the fire is quickly and easily
extinguished.

The longer the fire lasts and the fire temperatures
reach a maximum (about 1000°C/1832°F), the
more problematic it becomes for the steel and
reinforced concrete structures, especially in older
houses that do not have the latest fire protection
technology.

Concrete can easily withstand a temperature of
300°C/572°F for a longer time. At a temperature

above 400°C/752°F, the compressive strength of
the concrete decreases. At a temperature above
600°C/1112°F, volume increases occur in reinforced
concrete, which can lead to external flaking or
cracks within the concrete structure.

The time factor is a crucial factor for the stability
of the construction.
Today we try to increase the period of the temperature
penetration of the reinforced concrete construction
by higher concrete coverings.

We developed and produce UHPC HT which has
a temperature resistance over 1000°C/1832°F. So
far, this material has been used especially in the
steel industry, but it is certainly an interesting
material for the construction industry in certain areas.

UHPC HT materials remain stronger in all
temperature ranges than those of standard concretes.

That means no matter what temperature and
burn time, UHPC HT compressive strength
far exceeds that of standard concretes.

This quality of UHPC HT could mean for the
fire fighting, that the danger of a building collapse
is reduced by a multiple.

UHPC HT concretes combine them very well
with highly efficient insolation materials. From
the experience of the steel industry we know
that we can achieve extreme temperature
reductions even in very thin wall thicknesses.

 

WPE DK International

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