Road Pavement Structure
A flexible pavement consists of multiple layers: Sub-grade → GSB → WMM → DBM → BC.
GSB (Granular Sub-Base)
GSB is the first structural layer above sub-grade. Compaction: 98% of MDD. Thickness: typically 150–200mm.
WMM (Wet Mix Macadam)
WMM provides the base course with crushed aggregates. Compaction: 100% of MDD. Thickness: typically 150–250mm.
DBM & BC
DBM is the binder course (4–5% bitumen). BC is the wearing course (5–6% bitumen) providing the traffic surface.