Dynamic modulus
- Cyclic loading is applied and stress and strain are measured to characterize mixture stiffness.
- A range of temperatures and frequencies can be used to build a master curve and compare response under different loading conditions.
Rutting and fatigue
- A flow-number test tracks permanent strain over repeated cycles; a change in the deformation trend helps compare rutting susceptibility.
- Uniaxial fatigue cycles a specimen and tracks damage development; interpret results using the model and criteria in the procedure.
- Repeated-load methods, such as iRLPD or stress sweeps, characterize accumulated deformation under combinations of temperature and stress.
Cracking and specimen geometry
- The SCB test uses a notched semicircular specimen to study crack initiation and propagation.
- The Overlay test examines cracking resistance associated with reflective cracking; indirect-tension configurations can also use field cores.
- Smaller-diameter specimens may make field cores easier to test, provided their dimensions and representativeness suit the method.
Interpretation and control
- Compare results only when geometry, preparation, conditioning, temperature, and loading sequence match.
- Check alignment, instrumentation, contact, and repeatability. A performance result supports design; it does not replace field validation.
Mechanical indicators
- Dynamic modulus: |E*| = σ0/ε0; report temperature and frequency with each value. A master curve depends on the time-temperature shift model and data range used.
- Permanent strain: εp = Δh/h0. Report the εp-versus-cycle curve, not only flow number; flow number depends on the procedure’s inflection-point definition.
- Fatigue: Nf is the number of cycles to the stated failure criterion. The criterion may use stiffness loss, strain, or energy and changes the calculated life.
- SCB fracture: fracture energy can be expressed as Gf = W/Alig, where W is work integrated under the load-displacement curve and Alig is projected ligament area. State geometry, notch, and integration method.
Educational reference guide. Check the current standard, calculation assumptions, and project specification before applying a procedure or acceptance criterion.