How do concrete removers work?
Concrete removers generally fall into two categories, strong acidic and safe formula.
Acidic Concrete Removers
Acidic concrete cleaners operate through the action of strong acids, such as hydrochloric acid or phosphoric acid, to dissolve concrete and cement. Here's a breakdown of how they function:
1. Acidic Composition: These concrete removers are formulated with highly acidic compounds, chosen for their capacity to break down mineral-based deposits and stains effectively.
2. Chemical Reaction: Upon application, the acidic cleaner causes a chemical reaction with the alkaline compounds commonly found in concrete. The primary target here is calcium carbonate (CaCO3), a prevalent component in concrete.
3. Acid Dissolution: The acid interacts with calcium carbonate, inducing a chemical reaction that results in the creation of soluble calcium salts. A classic example involves hydrochloric acid:
CaCO3 + 2HCl (hydrochloric acid) → CaCl2 (calcium chloride) + H2O (water) + CO2 (carbon dioxide)
4. Weakening the Bond: As this chemical transformation takes place, the acid disrupts the molecular bonds holding the contaminants and the concrete together. This process effectively weakens the grip of the cement holding the concrete together.
Some acid-based products will fizz and bubble as this chemical reaction takes place, while others come as a foam which you leave to dwell. Always follow the manufacturer's dilution rates and instructions for use carefully.
5. Removal: Once the chemical reaction has occurred, the contaminants become more receptive to removal. Cleaning can be accomplished through various means, including pressure washing, or rinsing, leaving the surface free of the previously entrenched substances. Due to the delicate nature of car paintwork, and the abrasive nature of concrete, any removal method which involves agitation should be avoided.
6. Safety Precautions: It's important to exercise caution when working with acidic concrete cleaners, as their strong acidic nature can pose risks. Protective gear, including gloves, goggles, and proper ventilation, should be employed to minimize potential harm. As the safety of your car is also a concern, you should carefully monitor the condition of the paintwork throughout the process.
7. Neutralization: After using acidic cleaners, it's essential to neutralize any remaining acid on the surface. Neutralization can be achieved using alkaline based soaps, such as Traffic Film Remover, to ensure acid corrosion doesn't occur with re-wetting.
"Safe Formula" Concrete Removers
There are several products on the market which use marketing language similar to "A safe alternative to harsh acid cleaners", "Contains no harmful acids", or "does not contain mineral acids", which may give the impression that they are non-acidic. However, looking at their safety data sheets, they usually use an acid such as citric, carboxylic acid or carboxylic acid compounds - these are similar to the organic acids found in white vinegar.
Although these products are safe and can be effective, they have one major drawback, which is the concrete needs to be dry when they are applied. The method for concrete removal we have explained requires that you apply the product and rinse it off and keep repeating the process, and of course, we advise against attempting to dry the car. There are ways around this, by waiting or using heat, but they are not idea for removing heavy concrete contamination and are far more suitable for cement and limescale contamination.
Our Concrete Remover of choice is AutoSmart Congo which uses a Glycolic acid, which is organic and usually derived from sugar cane, however although safer for cars than some other products, it is still highly corrosive.
Written by Danny Argent. Last updated 21/02/2024 10:14