We are pleased to introduce you a latest innovative
technology solution in construction with ultra
high-performance concrete CRC pre-cast elements.
The high strength of concrete and very small cover to the
reinforcement can be used with the very dense
matrix, which makes it possible to produce very
light and slender structures.This is a cementitious
based material used with a high proportion of steel
fibres which enables monolithic construction by the
lapping of bars over very short distances.
Examples of new methods, when looking at long-term
performance and global cost-benefit balance. Include
pre-cast slabs, staircases, manhole covers, slender
beams, columns and facade panels, where has been CRC
engineered to its full potential!
UV ,
FROST , ACIDS and SALT Resistant
Maintenance free
Higher load bearings and greater spans
Durable, long lasting construction
Higher quality and security
Mountable in any weather conditions
CRC - Pre-cast Elements
CRC properties
CRC is the designation for a
special type of Fibre Reinforced High Performance
Concrete with high strength (150-400 MPa) developed by
Aalborg Portland A/S. Because of a large content of steel
fibres the matrix is very ductile and that makes it
possible to utilize rebars much more effectively without
having large cracks under service conditions.
The size of the fibres and the largest grains of the
matrix dictate the distance between reinforcing bars and
the cover layer to the reinforcement, both of which have
to be optimized in the slender structures, which can be
produced with CRC. This is the reason for typically using
a mortar composition for CRC and for using short fibres.
Often a cover layer of 10-15 mm and a similar distance
between individual bars are used.
With the high fibre contents, CRC is especially suitable
for pre-cast app-lications, but in-situ cast concrete
with 6% by volume of fibres has also been produced - for
joints between slabs made in conventional concrete -
using a poker vibrator for compaction. For these
applications a premix called CRC Joint-Cast is usually
supplied.
CRC has been the subject of a number of research projects
investigating mechanical properties as well as durability
and fire resistance. This information is necessary in
order to be able to use CRC for structural applications,
as this type of material is not covered in existing
standards and codes of practice.Mechanical properties
depend on type of aggregate, curing, content and type of
fibres, reinforcement etc., but they will typically be in
a range of:
The standard composition
of CRC with quarts sand and 6 vol.% of steel fibres
typically has a compressive strength of 140 MPa measured
on cylinders at 28 days. The flexural strength is
approximately 25 MPa. In design calculations a
characteristic compressive strength of 115 MPa is
used, and the reinforcement typically has a
characteristic strength (yield) of 550 MPa. Young's
modules of CRC is about 45 GPa. As the stiffness of CRC
is only marginally higher than the stiffness of
conventional concrete,it is often necessary to pay
special attention to deformations in design of slender
CRC structures.Fatigue tests demonstrate that CRC behaves
slightly better than conventional concrete, basically due
to an improved ability to redistribute internal stress.In
the table below expected mean values of a number of
properties are indicated as a function of the fibre
content of the matrix. Interpolation between the values
can be used to assess the properties of other fibre
contents. The uniaxial tensile strength shown corresponds
to the maximum stress that can be transferred in a
cracked section. Initiations of cracks occur at stresses
of 6-7 MPa depending on the fibre content.
