Formwork is recognised as a crucial aspect of the production of quality concrete, and moulds are similarly key in the manufacture of precast elements.

To achieve the desired aesthetics of concrete finishes, such as surface texture and colour, formwork surfaces require adequate preparation in terms of cleanliness and the selection of an optimal release agent.

Application-driven release agents have now been introduced by CHRYSO as a means of introducing flexibility to the industry, compared to previous one-size-fits-all products.

Different form-face materials have differing longevity, absorbency and texture characteristics and thus require application-specific release agents for the specific formwork selected to achieve certain aesthetics. Selecting an application-specific release agent also helps to save time and reduce material wastage.  

The CHRYSO DEM range of application driven release agents are said to provide greater coverage, ease of-use and consistent quality. The company further emphasises that the use of an optimal release agent reduces the likelihood of imperfections and surface defects, such as blow holes in the concrete, and also reduces the risk of staining or deviation from the specified colour finish.

The range includes the following products:

• Dem Bio 10: A vegetable-based, bio-degradable, environment-friendly and non-toxic release agent. It has a low odour and is therefore safe to use in confined spaces such as mining, tunneling and poorly ventilated areas. It is suitable for use with all types of formwork, including metal, wood, plastic, polystyrene and fibreglass.
• Elio VP: A hydrocarbon oil-based agent, suitable for use when producing concrete pipes with roller compacted pipe technology. The low viscosity oil creates less surface tension against the sides of the pipe steel moulds which results in less outer concrete surface damage when demoulding and reduced surface defects.
• Dem Oleo WB: A wax-based delayed-release agent for wooden formwork used on conventional jobsites and for wooden pallets for cement-based brick manufacturing. It temporarily protects and extends the life of veneer laminated shutter boards, decreasing the frequency of re-lamination. The release agent can also be used to coat pallets for protection, when stacked with cement-based bricks.
• Dem Oleo FW: Is hydrocarbon-based[DS1]  and suitable for use with all types of formwork. It is however not suitable for precast applications. It ensures ease of formwork release and also temporarily protects and extends the life of metallic formwork from corrosion.
• DEM Oleo SM: A mineral-based delayed-release agent, suitable for use with metallic or wooden formwork for wet precast. It does not stain or affect the colour of the concrete, when applied correctly. Particularly useful when white cement is used for specialised architectural finishes. It is formulated to handle the high temperatures of steam curing and provides rust prevention. The hydrocarbon oil-based delayed release agent is used for steam cured precast elements cast in steel formwork.
• Dem Oleo RT: A hydrocarbon oil-based, delayed-release agent for the roof tile industry, developed specifically for use with aluminum roof tile pallets.

The company says that its ready-to-use range of release agents reduces the likelihood of errors, especially when mixing of various components is required. It asserts that when applied correctly and for the correct purpose, its range does not modify cement hydration and as it is water repellent, it is not affected by rain.

While generally regarded as a minor item on the bill of quantities, the specification and selection of an appropriate release agent and application method may prove to be critical to the success of a project, affecting both the quality and colour of the surface finish. It is thus seen as crucial to use the appropriate release agent for the correct application and formwork substrate, in order to protect and extend the life of formwork or moulds.