What is the recommended slump for flatwork concrete?

The recommended slump for flatwork concrete typically falls within the range of 3 to 5 inches (75 to 125 mm). This slump is ideal for achieving a good balance between workability and stability during finishing operations. A slump within this range ensures that the concrete can be easily placed and finished without excessive segregation or bleeding, which can compromise the integrity of the surface.

Concrete with a slump that is too low may be difficult to work with, leading to problems such as inadequate filling of forms or surfaces. Conversely, a slump that is too high can result in excessive water, which can weaken the overall strength of the concrete and lead to long-term issues like cracking and scaling. Therefore, maintaining a slump between 3 to 5 inches allows for optimal performance in flatwork applications, ensuring better placement, finishing, and overall durability of the finished surface.