Pavement evaluation

Pavement evaluation is the systematic collection and analysis of data on the present condition of a pavement (surface and structure), so that the need for maintenance, strengthening or reconstruction can be decided and priorities set.

Functional evaluation (ride quality and safety)

• Roughness - measured by bump integrator, MERLIN, Roadroid (smartphone) or profilometer, and expressed as the International Roughness Index (IRI, m/km); IRC:SP:16 gives evenness limits, and Nepal DoR uses roughness in its road maintenance management system.
• Skid resistance - pendulum tester (British Pendulum Number), skid trailer.
• Surface distress - visual condition survey of cracks, potholes, rutting, ravelling, bleeding and patching (IRC:82 and the Nepal DoR condition survey).

Structural evaluation (load capacity)

• Deflection tests (non-destructive) - Benkelman beam (IRC:81), Falling Weight Deflectometer (FWD), Lacroix deflectograph.
• Destructive tests - test pits and cores to find layer thickness, density and subgrade CBR; Dynamic Cone Penetrometer (DCP) for in-situ strength.
• Other tests - Ground Penetrating Radar (layer thickness, non-destructive), plate load test on exposed layers, and back-calculation of layer moduli from FWD data.

Use: the results give a condition index, which is combined with traffic to select the treatment: routine maintenance, periodic maintenance, overlay (strengthening) or reconstruction.