Anton Paar Smart Pave DSR. The dynamic shear rheometer (DSR) is used to characterize the viscous and elastic behavior of asphalt binders at medium to high temperatures. This instrument is used to study the rheological properties of asphalt binders.
Asphalt binders are viscoelastic. This means they behave partly like an elastic solid (deformation due to loading is recoverable – it is able to return to its original shape after a load is removed) and partly like a viscous liquid (deformation due to loading is non-recoverable – it cannot return to its original shape after a load is removed). The DSR measures a specimen’s complex shear modulus (G*) and phase angle (δ). The complex shear modulus (G*) can be considered the sample’s total resistance to deformation when repeatedly sheared, while the phase angle (δ), is the lag between the applied shear stress and the resulting shear strain. The larger the phase angle (δ), the more viscous the material. Phase angle (δ) limiting values are:
- Purely elastic material: δ = 0 degrees
- Purely viscous material: δ = 90 degrees
G* and δ are used as predictors of hot mix asphalt (HMA) rutting and fatigue cracking.
A small sample of asphalt binder is sandwiched between two plates. The test temperature, specimen size and plate diameter depend upon the type of asphalt binder being tested. Unaged asphalt binder and RTFO residue are tested at the high temperature using a specimen 1 mm thick and 25 mm in diameter. PAV residue is tested at lower temperatures. These lower temperatures make the specimen quite stiff, which results in small measured phase angles (δ). Therefore, a thicker sample 2 mm with a smaller diameter 8 mm is used so that a measurable phase angle (δ) can be determined.
CSIR-Central Road Research Institute,
Delhi-Mathura Road, New Delhi-110025
Phone: 011-26832173, 26832325
Email: director [dot] crri [at] nic [dot] in
Instrument Usage Charges(Including GST)
IndustryUniversities/IITsNational LabsRs 75000/- per sampleRs 25000/sampleRs 25000/sample