Zemdrain® controlled permeability formliner

The primary cause of concrete degradation is the poor quality of the outer 20mm of the surface due to the use of oiled impermeable formwork. The resulting surface has increased porosity and numerous blowholes and reduced durability.

Zemdrain® controlled permeability formwork (CPF) liners are attached to the formwork face and during the concreting process remove excess air and water from the formwork/concrete interface. The resulting high quality concrete surface has significantly increased durability properties.

Concrete formed with Zemdrain® has the following benefits:

• Virtually blowhole and blemish free surfaces
• Surfaces uncontaminated by release agent residues
• Surfaces with a lower w/c ratio
• Increased surface hardness and density
• Increased chloride and carbonation resistance
• Improved freeze/thaw resistance
• Improved abrasion resistance

The improved concrete properties produced by the use of Zemdrain® result in many benefits for asset owners:

• reduced the whole life costs of all concrete structures
• time to initial maintenance is reduced
• time to onset of reinforcement corrosion significantly increased
• for potable water structures – water quality is maintained as there is no possibility of concrete contamination as release agents are not used
• For wastewater structures – the effects of acid attack are reduced prolonging the life of concrete surfaces
• The time for cleaning and the quantity of cleaning chemicals required is reduced
• Potential damage during the cleaning process is minimised
• Operational downtimes during refurbishment are shortened
• For bridges and marine structures the rate of chloride ingress is halved

Zemdrain® can be used for all concrete structures. However, the principal uses are for infrastructure projects such as drinking water reservoirs, water treatment plants, wastewater treatment plants, sewage treatment plants, locks, bridges and marine structures. Quality exposed concrete surfaces can also be produced using a Zemdrain® liner.

There are two different types of Zemdrain® – Zemdrain® Classic and Zemdrain® MD. Both liners give the same levels of improvement in concrete performance, however, their use and fixing to various formwork systems is different.

Zemdrain® CPF liners can be incorporated with Tubbox® column formers.

Zemdrain® is DuPont’s registered trademark. www.zemdrain.com