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Surface treatment
This page presents a
general description on applying Surface Treatment.
Incorporated within the page is also a tool to calculate the total
cost of applying Surface Treatment. While concrete is often
considered a durable material it may in certain circumstances require
protection. Following
deterioration and repairs, or in the absence of sufficient cover to
protect reinforcement, there is often a requirement to provide protection
against penetration by water, carbon dioxide, sulphur dioxide and salts.
Protection against long-term
deterioration is also a possible requirement. Additionally, there is an
increasing need for decorative or colouring treatments to improve the
quality of the surroundings where these contain large areas of concrete,
or even for colourless waterproofing treatments to prevent accumulation of
dirt and biological growths. Refer to Section 4.3 and Section 8 of the guidance document
to provide more guidance on the selection of
coatings for concrete. Activate this tool, Coating to calculate the cost
of applying surface treatment. The main inputs
expected within the tool below are the
'Cost
per Surf. Treatment', 'No of Surface Treatment'
and
'Area
to
be Treated' .
The cost
relating to the technique can be found by activating the Costing links within the
tool. Multiplication of the
two main inputs generates a total cost for the specified technique.
This cost is then added to the 'Fixed
Cost' to produce a total
cost for applying the technique from conception to finish.
The
first and last three inputs which are the'Name
of the Technique', 'Maintenance Cost' ,
'Life
of Technique' and 'Life of
Retreatment' are essential if the user requires the output generated by
this tool for future reference. The
generated output is presented in a report format which contains the
specified technique as well as other details relating to the calculation
. The output
produced within the Total Cost text area can then be
copied and pasted within a report or a document for future reference
. Three generic types
of surface treatment are available for the decoration and protection of
concrete surfaces, designed to control chemical ingress as well as
moisture movement. They are described as follows:
·
Pore-liners–
these
are
hydrophobic impregnation treatments such as silicone impregnants, which
line the pores of concrete. They repel water and therefore prevent it from
entering the concrete, but continue to allow water vapour to
escape.
·
Pore
blockers – these are materials that partially or completely block the
pores in concrete. They may accomplish this by either reacting with the
concrete to produce pore-blocking products or by physically blocking the
pores.
·
Film-formers – these
are coating systems based on either organic resins such as styrene
butadiene and acrylic copolymers or inorganic resins such as potassium
silicate, which form a protective/decorative film on the surface of the
concrete. Coatings may be endowed with special properties, such as the
ability to bridge moving cracks whilst maintaining film
integrity.
Film-forming coatings
for concrete are principally decorative protective elastomeric products.
They are formulated to form a barrier against the ingress of carbon
dioxide, and other deleterious substances, yet allow the free passage of
water vapour. They should exhibit a proven resistance to weathering, and
maintain their elastomeric and barrier properties in service, which will
often be a maintenance free life in excess of 10 years. Test certificates
should be sought to demonstrate these properties.
Most
surface treatment for concrete can be a combination of the types of
surface treatments discussed above
There is no ideal set
of requirements, which will lead to the selection of appropriate coating
systems. ·
The
coating often has to fulfil several requirements at the same
time. ·
Different products
may satisfy the same specification, but to different levels of
effect. ·
The
products of the same generic type can exhibit marked variations in certain
properties as a result of different formulations. ·
At
present there are no agreed and quantified performance criteria. European
Standards for coatings on concrete will introduce quantified performance
criteria, as part of the EN 1504 series. ·
There is
no direct relationship between test data and
in-service. Further information
on surface treatment can be obtained from the Guidance Document |