Cleaning concrete might seem to be a straightforward process, but some things must be understood.
There are two cleaning methods that can be used: mechanical and chemical. Both will work in the right situation. No matter which one is selected, performing regular cleaning will extend the concrete’s service life.
Mechanical Cleaning
The least destructive mechanical cleaning method is when a brush is used. The brush can be a small handheld model or an attachment used on a low-speed (175 rpm) floor buffer (swing machine). The bristles can be made of horsehair, plastic, silica-carbide, or metal. This cleaning method is usually combined with a chemical cleaner. The scrubbing action aids in loosening the contaminate away from the substrate as the chemical breaks it down.
Pressure water washing is considered a mechanical means. The high-pressure water physically removes the contaminate without the use of a chemical. When only cleaning, the pressure needs to be lower than the compressive strength of the concrete. At this pressure, the water will only remove poorly bonded materials with minimal disruption to the surface. If the surface is weak, that will also be removed. This is an excellent method when cleaning exterior concrete.
Hot water pressure washing is an incredibly effective way to clean concrete. When using hot water, the pressure can be lower than traditional pressure washing methods while increasing the volume (CFM). The greater the amount of hot water applied at a lower, less destructive pressure, the more efficient the cleaning action will be.
Abrasive blasting is another mechanical cleaning method where an abrasive is propelled to the substrate. This could be performed using a walk-behind shot blaster or compressed air blaster. Different blast media can be used based on the substrate being cleaned. The abrasive can consist of walnut shells, sand, glass beads, steel shot, or boiler slag (black beauty). Although it can remove ground-in dirt, leaving the surface almost spotless, this action can be overly aggressive and change the surface texture. Only a trained operator should try this process otherwise, the surface could be damaged and need repairing.
An abrasive can also be used with water. Great care needs to be taken when this method is used. It can also be aggressive and etch the surface. Typically, when using a blasting method, the operators’ goal is to prepare the surface to accept a coating system. For this, the surface needs to be clean and rough. This allows for a good, mechanical bond for the coating system.
Chemical Cleaning
Chemical cleaning can be a little tricky. Selecting the proper chemical for the substrate and contaminate is critical. When polished concrete was initially brought to the forefront, the complaint was about the cleaning process. Commercial cleaning companies were not being instructed on how to deal with the shiny, concrete surface. The typical cleaning solution they used had a high pH level. These cleaners do a wonderful job cleaning VCT, epoxy systems, and other hard surfaces. They will not work on a polished concrete floor without harming the surface.
A concrete cleaner needs to be pH neutral. This means it has a similar pH to the substrate it is cleaning. Concrete has a pH of 9-10, so the cleaner must be the same. If it is higher or lower, etching will occur.
The chemical cleaning process involves the removal of a substance from the surface or just below it. This substance can range from dirt, oil, grease, or even a sealer/coating. The chemical needs to be able to break down or emulsify the contaminate for easier removal. Always select the chemical based on what is being removed.
Routine-use cleaning chemicals will work well when removing dirt and grease. DiamaPro® Diama-Clean 30 is a good example of a product that can be used in an auto-scrubber to perform daily cleanings. It will aid in the removal of most common contaminants.
When there is oil saturation, there are two commonly used chemicals, poultice and hydrocarbon-eating microbe materials. Poultice is a highly absorbent material that draws oil from a concrete surface. Look for a poultice-style cleaner that uses powerful solvents to draw out deep-set stains. Poultice cleaners are applied in a thick paste to stain-plagued areas. As the product dries, it draws contaminants up and out of concrete pores. One thing to know when using a poultice is that it might rid the near surface oil, but the stain produced could remain. Used oil has contaminates that will leave a stain.
Using hydrocarbon-digesting microbes can be highly effective when working with oil saturation. They can clean up petroleum hydrocarbons - oil, gasoline, diesel, fuel oil, and more. The microbes are selected with known appetites that target petroleum-based hydrocarbons. These microbes penetrate deep into the pores of hard surfaces to degrade a wide range of embedded oils, diesel, gasoline, paraffin, and more.
The key step in the degradation of hydrocarbon contaminants depends on the presence of a multi-component enzyme system found in these microorganisms. These microbes are easily applied to the site or spill and digest their way through the pollutant material, multiplying and digesting until no more pollutants are present. Microorganisms use these unwanted hydrocarbon contaminants as their fuel source. The byproducts they excrete are a blend of non-toxic carbon dioxide and water.
When concrete is placed, the last step is to apply a curing membrane. These film-forming membranes are normally acrylic. As time passes, they start to break down and fail from use and exposure to weather on an exterior slab. This is a normal process. When it is time to reseal, the curing membrane needs to be removed. This cleaning process takes a special cleaner that softens the compound without liquifying it so it can be removed with a clean water wash. If it becomes a liquid, it will absorb deeper into the surface, causing further issues.
Factors to Consider When Choosing Concrete Cleaning Chemicals
Cleaning chemicals have their place in the world of keeping your facility safe while retaining the original appearance. They need to be used in the right situation and substrate. If using a chemical for the first time, it is highly recommended to evaluate it in a small area. This will help you to figure out if it will have a negative impact on the surface and how well it removes the contaminate.
Tips for Using Concrete Cleaning Chemicals Safely and Effectively
Cleaning solutions might contain chemicals that are harmful to the skin and eyes. Read the cautions printed on the tech data and safety data sheets (SDS). Granted, the SDS will publish every known issue with the solution, but still, read them before starting.
Wearing the proper Personal Protection Equipment (PPE) is highly recommended when chemical cleaning. Eye and skin protection is necessary. With harsh chemicals, a respirator should be worn. Even if the technical data indicates it’s a safe cleaning alternative, you or your employees may be allergic to one of the chemicals, which is why proper PPE is important.
Always read the technical information provided by the manufacturer. If it needs to be diluted, follow the instructions provided. If they say chemical-resistant clothing must be worn, wear it. If they recommend safety precautions, follow them for your safety, your employees, and others in the area.
Conclusion
Cleaning your concrete floor to keep its appearance and original slip resistance is unavoidable. There are several benefits why a concrete floor is an excellent choice for your facility and one is how easy it is to keep. By choosing the proper cleaning method, chemical or mechanical, your concrete floor will equal the original intent.
If deciding the method is foreign to you, DiamaPro Systems can help. We supply contractors and facilities with solutions that will make the process easier. Whether using mechanical or chemical, we have what it takes to get the job done without harming the substrate.
When tackling a large project, ride-on auto-scrubbers will enhance the process, along with reducing the time spent. When using a cleaning chemical such as DiamaPro Diama-Clean 30 and diamond impregnated pads, these floor scrubbers can be amazingly effective.
A well-maintained floor is both aesthetically pleasing and safer than a dirty one. Using the right cleaning method, your floor will not only look better, but will also be safer while providing a long service life.