FDOT Earthwork Level 1 Practice Test

Lift thickness sets the depth that the compaction energy can effectively penetrate in a single pass. Densifying soil relies on the roller delivering energy through the lift to rearrange particles and reduce air voids throughout the layer. If the lift is too thick, the energy doesn’t reach the full thickness, so the top portion may dense up while the bottom remains loose, producing nonuniform density and requiring more passes or rework. That’s why lift thickness directly controls whether the compaction equipment can achieve the required density and uniformity. The other choices aren’t about how well compaction works—color isn’t tied to density, changing soil type isn’t caused by lift thickness, and grade line relates to elevation control rather than single-pass compaction depth.