Lean concrete is a mix where the amount of cement is lower than the amount of liquid present in the strata. This makes it ideal as a base layer where other kinds of concrete are placed on top. It is good for providing a flat bottom in uneven or dirt terrain.
Concrete with high water content is considered lean because it has a lower concentration of cement compared to other kinds of paving and building materials of that class. It is often used as a plaster between bricks or other pieces of infrastructure to create a tight seal. Lean concrete cracks over time when it is not applied properly or mixed to the right specifications. Careful preparation is key to successful lean concrete.
Lean concrete is commonly used in road construction as the lowest level under the pavement on which vehicles travel. It serves as a sub-base in projects where the ground itself is not a suitable resting place for a project to begin, thereby giving roads and buildings a stable platform on which to rest.
A lean concrete mix is measured in pounds per square inch. In the right conditions, lean concrete flows like a liquid and makes for easy applications. It usually is not used in cases where more than 2 inches of sub-base or ground clearance is necessary.