Concrete oily release agents are widely used in construction due to their excellent isolation and demolding properties. However, if the oily residue left on the formwork surface after use is not thoroughly cleaned, it can affect subsequent construction quality and the lifespan of the formwork. Cleaning the formwork after using concrete oily release agents requires a combination of scientific methods and tools tailored to the characteristics of the oily substance to achieve efficient and non-destructive cleaning.
Pretreatment of the formwork is necessary before cleaning. First, inspect the formwork surface for large chunks of concrete residue. If present, carefully remove them with a scraper or spatula to avoid damaging the formwork substrate. For metal forms like aluminum, special care must be taken to prevent scratches that could lead to corrosion. For wooden or steel forms, attention should be paid to whether residue has seeped into crevices. During pretreatment, the formwork should also be checked for flatness to ensure even contact with subsequent cleaning tools.
Mechanical cleaning is a key step in removing oily release agent residue. High-pressure water jets are commonly used, effectively stripping away oily films and other debris by impacting the formwork surface with high-pressure water. During operation, maintain a 30-45° angle between the water gun and the formwork, moving the water gun at a constant speed from one end to the other to avoid excessive cleaning and deformation. For stubborn oil stains, add an appropriate amount of neutral detergent to the water to enhance emulsification. Carefully control the water pressure to prevent high-pressure water from damaging the formwork surface coating.
Chemical cleaning is suitable for situations where oily substances have penetrated deeply. It is crucial to select a cleaning agent that is compatible with the release agent. Alkaline cleaning agents are particularly effective with animal and vegetable oil-based release agents, while solvent-based cleaning agents are more suitable for mineral oil-based products. Spray the cleaning agent evenly onto the formwork surface and let it sit for 5-10 minutes to fully dissolve the oil film. Then, wipe with a soft brush or sponge. Wipe in the same direction as the formwork grain to avoid scratches. After cleaning, rinse thoroughly with clean water to prevent chemical residue from affecting subsequent work.
Heat treatment cleaning is an effective supplemental method for special working conditions. Heating the formwork to 60-80°C reduces the viscosity of the oily substance, making it easier to remove. Heating can be done with a heat gun or infrared heater. Care must be taken to maintain temperature uniformity to prevent local overheating that could cause formwork deformation. Mechanical cleaning should be performed immediately after heating to accelerate the removal of the oil film due to thermal expansion and contraction. This method is suitable for winter construction or when the oil film has solidified significantly.
For difficult-to-reach areas such as formwork joints and corners, manual cleaning is required. Use a fine-bristled brush dipped in detergent and repeatedly scrub along the gap to ensure complete dissolution. For stubborn residue, use a small amount of solvent-based detergent with cotton wool to rub it locally. Wear protective gloves during this operation to prevent skin irritation from the solvent. After cleaning, inspect the gaps for residual detergent to prevent any degradation of the concrete bond.
After cleaning, the formwork must be dried and protected. Air drying is preferred. The formwork should be laid flat in a well-ventilated area to avoid direct sunlight that could cause local deformation. After drying, inspect the surface for any remaining water stains or detergent marks. If present, wipe with a clean cloth. Before long-term storage, apply a thin layer of protective oil to the formwork surface to prevent rust and oil film degradation. The protective oil should be compatible with the release agent to avoid chemical reactions.
Regular maintenance and standardized operation are key to extending the life of the formwork. A cleaning record should be created after each use, documenting the cleaning method and results to provide a reference for subsequent maintenance. During storage, avoid contact between formwork to prevent deformation. For reused formwork, regularly inspect the integrity of the surface coating and promptly repair any peeling or corrosion. Through a scientific cleaning process and standardized maintenance management, you can ensure that the formwork is always in optimal condition, providing a reliable guarantee for the quality of concrete construction.
