This notice advises that the new sealing chip specification is available to be used for all future chipsealing works. The new specification will come into effect immediately and should be applied to all upcoming chipsealing works in the State Highway Programme.
This notice advises that the new sealing chip specification is available to be used for all future chipsealing works. The new specification will come into effect immediately and should be applied to all upcoming chipsealing works in the state highway programme.
This document sets out best practice for the production of aggregate including minimum frequency of sampling and testing. The new specification controls the quality of the rock feedstock used for the manufacture of sealing chip and sets limits around criteria for five grades of chip.
This notice replaces Technical Advice Note #17-08.
Over the past several years alternative materials have been used to manufacture sealing chip to create polishing-resistant seals that retain their skid resistance over the design life of the seal. This update to the M6 specification also regularises the use of such materials.
There are other changes to M6 specification covering the control of the source rock quality used for manufacturing sealing chip. These changes have become more prescriptive, and include:
The specification is now available online at https://www.nzta.govt.nz/resources/sealing-chip/
The drive to provide skid resistant pavement surfacings that retain their skid resistance over their lives has created a demand for chip aggregates that do not polish. While there are some natural rock aggregates that perform well in high stress situations where aggregate polishing can occur, synthetic materials such as Glenbrook Melter Aggregate (GMA), have been found to perform very well in comparison. The changes to M6 allow the use of GMA chip aggregates, to reflect current chip sealing practice. The changes include:
The Polished Stone Value test, BS EN 1097-8 specifies a UK-sourced control stone, used as a reference aggregate in the test to standardise the test results. This control stone is difficult to obtain, so a New Zealand sourced control stone has been identified and M6 specifies amendments to the Polished Stone Value test to allow the use of this stone.
Some changes have been made to the specified properties of the sealing chip. These include:
The notes to M6 have been extensively rewritten. Changes include:
The value to producers, chip sealing practitioners and asset owners include:
Author: New Zealand Transport Agency
Published: June 2019
Found at: https://www.nzta.govt.nz/resources/sealing-chip/
To submit documents or if you have any questions or feedback, please contact the NZTA Principal Surfacings Engineer, Grant Bosma at firstname.lastname@example.org
David Darwin Vanessa Browne