New specification testing for modified binders

Austroads have announced updated specification testing for polymer and crumb rubber modified binders in sprayed seal and asphalt.

According to a spokesperson for Austroads, modified binders are used by material processing companies to enhance the performance of binders on heavily trafficked or distressed pavement surfaces.

“The test method has been revised following a review of current modified binder manufacturing, testing and application experience,” the spokesperson said.

“Specification limits are framed around the results of nationally coordinated field trials and laboratory studies, supplemented by Austroads jurisdiction experience.”

Changes include:

  • Adding an alternative Standards Australia method for determination of viscosity at 165 degree celsius.
  • Adding a stress ratio binder property.
  • Removing the consistency and elastic recovery binder properties.
  • Replacing the rubber content by analysis binder property for the class S45R binder with a stipulation that this binder class be manufactured from crumb rubber derived from used vehicle tyres.
  • Adding a definition for field-produced crumb rubber modified binders.

 

“These specifications aim to achieve satisfactory design performance in the field for both sprayed seal surfacing and asphalt pavement applications,” the spokesperson said.


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