Lean concrete is the concrete that has less water-cement ratio having less percentage of cement paste. In which aggregates are lean together with very less cement paste, it is usually a low slump concrete used in the construction of footings and foundations.

Most concrete has a PSI rating of 2500 to 3000. This type of concrete can be used for sidewalks and residential driveways. This concrete is generally more affordable than higher strength concrete.

Concrete with a PSI of 3500 to 4000 is typically used for concrete beams and footings. It can also be used for slab foundations and high traffic roads.

Concrete with a PSI of 4000 to 5000 is found in warehouses and factories, in addition to other large-scale commercial and industrial properties.

Concrete with a PSI rating of 6000 or more is considered high-strength concrete. It is typically found in nuclear power plants and other areas where radiation contamination is possible. High strength concrete has a lower water-cement ratio, giving it additional durability and strength.