New concrete turning brown or discolored can be unsightly to an otherwise exquisite pavement or brutalist wall.
Concrete discoloration can be attributed to inconsistent mixtures, too much or not enough water, and low-quality materials. Tracing back to the process can take the valuable time needed for construction.
It is more advisable to try fixes at this phase and observe better precautions on upcoming concrete works to prevent reoccurrence. This article covers concrete discoloration causes, fix, and preventive measures. If you’re ready, let’s start.
Types Of Concrete Discoloration And Their Fix
The effects of discoloration can be tricky to deal with. In the worst cases, it may give your concrete an uneven appearance that is an eyesore. Mostly, concrete discoloration revolves around materials inconsistency or even poor craft.
However, there is usually a root cause for these problems, and figuring it out will let you work much more smoothly in future jobs.
Here are some things discoloration causes to check and fixes you can try:
De-Icing Salt Effect
De-icing salts and pellets can cause discoloration, but this is not always made known by manufacturers. Sometimes it’s an issue with the manufacturing process. Oil or grease leaches into deicers during production, changing color once applied on surfaces.
Before applying these products for any type of treatment plan, ensure testing first. Otherwise, it can adversely affect a large area that can be irreversible. The first step if you experience this issue is to contact the manufacturer. If this fails, proceed to manual cleaning.
Among the steps you can do is using a heated pressurized washer or degreaser. If all cleaning methods fail to give desirable results, it is better to consider recoating to conceal the discoloration.
Effect Of Admixtures Like Calcium-Chloride
Admixtures like calcium chloride, which accelerates concrete setting time, may sometimes be necessary for concrete works. However, it can cause a darker concrete appearance. This effect is more apparent on higher mixture contents or around 2% up.
If such a problem occurs, better ask advice from the manufacturer or try bleaching the surface with a mild acid wash.
Efflorescence is often mistaken for mold or powdery mildew. It is a substance caused by moisture that seeps into the pores and carries along with this white powder-like substance. It looks similar to fungus growth around windowsills.
The good thing is that efflorescence can be dissolved and rinsed by water. However, surfaces affected by efflorescence should be treated to prevent recurrences. For best results, a specialized cleaner is advisable. Later on, you should apply densifiers and water repellents as sealers.
To avoid having an objectionable color issue, it is important to maintain consistency throughout the project. This includes maintaining mix proportioning and ensuring that different batches do not result in a mismatched hue across your installation.
In addition, materials and mixtures following standards like ASTM can help mitigate inconsistencies.
Of course, human error is among the possible causes of discolored concrete. The site can undergo varying conditions that can affect the quality of concrete curing. For example, concrete may need to be rinsed with a bit of water during intensely high temperatures to prevent cracks later on.
However, additional water if mismanaged can cause surface “bleed,” non-uniform surface appearance, or delamination. A competent mason or worker who knows what to do is necessary for crucial concrete works to prevent this issue from happening.
Use Of Cement Alternative
“Green” concrete alternatives are of increasing popularity. However, some of these alternatives can cause concrete discoloration and yield varying surface appearances. You might have to consider a different final surface coating to fix this, as the issue stems from the mixture itself.
You may also try acid washing, but you might have to go with the former if it does not yield any desirable results.
Water Content Discoloration
Mismanaged water content during curing can also discolor your concrete. There are also cases where the substance content of the water causes discoloration. For example, new concrete turning brown may be caused by excessive mineral or iron content.
To fix this, an acid rinse or heated pressure cleaning will work. Post-cleaning sealing might also be necessary if discoloration reoccurs.
How To Prevent Concrete Discoloration
You can easily avoid concrete discoloration by getting a contractor who knows what they are doing. This can save you a lot of hassle, especially if you’re not versed with concrete works.
However, if you are confident in starting this as your DIY project or a contractor yourself, checking the preventive tips below might help you a lot.
- Use standards-compliant materials. You can refer to the American Society for Testing and Materials (ASTM) to check whether the product passes the standards.
- Create a well-leveled subgrade to help ensure concrete curing uniformity.
- Avoid admixtures that can cause discoloration like calcium chloride.
- Observe proper curing processes, especially under varying weather conditions.
- Don’t do surface finish techniques that may cause discoloration if unfamiliar. Surface trowelling and the “sponge” effect are among the skills that might require more experienced hands.
Prevention Is Better Than Fix
Concrete work is a much more delicate job as it appears. Careful and proper observance of standards can help prevent surface issues like concrete turning brown and other discolorations. Preventive measures are more desirable than time-consuming fixes later on.