NICET - Highway Construction Inspection Practice Exam

What is the accepted surface deviation for Portland Cement base course measured with a 10 foot straight edge?

1. 1/8"

2. 1/4"

3. 1/2"

4. 3/8"

The correct answer is: 1/4"

The accepted surface deviation for Portland Cement base courses measured with a 10-foot straightedge is indeed 1/4 inch. This tolerance is important to ensure that the pavement provides a smooth surface for vehicles, reduces the risk of tire wear, and maintains proper drainage. When a straightedge is applied over the surface, the maximum allowable gap beneath it indicates how much deviation from the desired surface flatness is acceptable before corrective action needs to be taken. This specification is part of construction quality control measures to maintain the integrity and performance of the pavement. Choosing a tolerance of 1/4 inch strikes a balance between allowing some variability in the construction process while also ensuring that the final surface meets performance standards. This standard is typically outlined in project specifications or guidance documents, which reflect industry best practices for roadway construction.