Residual Pavement Design Life using FWD

Process Flow (Residual Pavement Design Life using FWD)

graph TD A[FWD Testing] --> B[Backcalculate Layer Moduli] B --> C[Compute Critical Strains] C --> C1[Tensile Strain @ Asphalt Bottom → Fatigue Eqn.] C --> C2[Compressive Strain @ Subgrade Top → Rutting Eqn.] C1 --> D[Compute Allowable Fatigue Life] C2 --> E[Compute Allowable Rutting Life] D --> F[Compare with Traffic ESALs] E --> F F --> G[Remaining Capacity = Allowable - Consumed] G --> H[Residual Life = Remaining ÷ Annual ESALs] H --> I[Smaller of Fatigue & Rutting Governs Life]

Quick Residual Life Calculator

Inputs (from FWD backcalculation)

Asphalt modulus, E_bit (MPa): 2000 MPa (Weak) 3000 MPa (Average) 4000 MPa (Good) 5000 MPa (Very Good)
Tensile strain @ Asphalt bottom (µstrain):
Compressive strain @ Subgrade top (µstrain):

Traffic Data

Past Consumed ESALs (million):
Annual ESALs (million):