The use of too much or not enough water. The use of calcium chloride. Improper concrete laying techniques. Outside temperatures.
Why Is My Concrete Spotted?
Concrete is an incredibly versatile and durable material that is often used in home construction and remodeling projects. It is also susceptible to damage, though, which can be manifest in the form of concrete spotting. Concrete spotting is when small, often circular, spots form uniformly on the concrete. This results from a chemical reaction between elements in the concrete and pollutants in the air. Understanding why concrete spotting occurs can help you treat concrete spots and prevent them from forming in the future.
The concrete spotting that develops on a concrete surface is caused by several reasons. One reason is moisture. Moisture in the air or on the concrete can create a moist environment for corrosive chemicals to react in. This can lead to areas of staining on the concrete surface. Another contributing factor is acid rain, which is caused by a reaction between sulfur dioxide, nitrogen oxides, and ozone in the air. Acid rain can penetrate the pores of the concrete and cause the staining to occur.
The pollutants that cause concrete spotting are most common in an urban setting. Automobile exhaust combined with industrial pollutants can create a chemical cocktail in the air, forming concrete spots. More intense periods of pollution often lead to more pronounced spotting