From material selection to service
- Binder selection is part of mix design. Performance grading relates the binder to expected pavement temperatures.
- Response depends on temperature, loading time or rate, and ageing; one measurement cannot describe all behaviour.
Conditioning and tests
- Short-term conditioning represents changes associated with production and paving; long-term conditioning simulates further ageing in service.
- Rotational viscosity characterizes resistance to flow at the test temperature and helps assess workability.
- A dynamic shear rheometer applies oscillation to a thin specimen to study stiffness and viscoelastic response; a bending beam rheometer evaluates low-temperature flexure.
How to compare
- Compare unaged and conditioned material using the same method and specified temperatures; report each specimen’s ageing condition.
- Relate high-, intermediate-, and low-temperature tests to risks of permanent deformation, fatigue, and thermal cracking, respectively.
Scope
- Binder tests do not replace mixture testing: interaction with aggregates, air voids, and compaction also governs performance.
- This guide summarizes concepts. Check current standards and project specifications for procedures, temperatures, and acceptance criteria.
Rheological parameters
- DSR complex modulus: |G*| = τ0/γ0, where τ0 is shear-stress amplitude and γ0 is shear-strain amplitude. Report temperature, frequency, and ageing condition.
- Components: G′ = |G*| cos δ and G″ = |G*| sin δ. G′ is the elastic component and G″ the viscous component within the linear sinusoidal response; δ is the phase angle.
- BBR stiffness: S(t) = σ0/ε(t), applied stress divided by creep strain at time t. The m-value describes the slope of log S against log t and is calculated as specified by the procedure.
- These parameters depend on temperature, frequency, geometry, and conditioning. Do not combine original and aged binder results or extrapolate beyond the measured range.
Educational reference guide. Check the current standard, calculation assumptions, and project specification before applying a procedure or acceptance criterion.