Scam alerts: we’ve seen an increase in scam texts and emails claiming to be from us, asking for payments.
Check our example scams or report a scam to us

NZTA App: our mobile app provides a simple and secure way to access your driver licence and vehicle information.
Learn more and download the NZTA app

Resources

Back to Resources

Method of measuring the active adhesion between a bituminous binder and a chip seal aggregate (T31)

Published: | Category: Construction , Chipsealing , Specifications | Audiences: Road traffic engineers & consultants, Roading contractors

The T31 laboratory test method is used to quantify the adhesion between a bituminous binder dosed with adhesion agent and a mineral aggregate. The use of adhesion agents is mandatory in cutback bitumen sued for chip sealing and T31 provides a process to optimise the dosage rate of adhesion agents in binders.

The areas covered by the method include:

  • materials and apparatus required
  • testing procedures—two alternatives are described
  • reporting requirements.

T31 is a new specification.

Publication details

  • Author:
  • Published: June 2025
  • Reference: NZTA T31
  • Contact: pavements@nzta.govt.nz
  • Conditions: This specification is mandatory for state highways and recommended for local roads.
  • Also known as: T/31