The Transport for NSW’s Test Method Review Committee is currently in the process of revising Test Method T147 – Working Time for Road Construction Materials (Blended in the laboratory with slow setting binders) Issue No. 3, 2022.
Scope
The Test Method T147 illustrates the procedure for determining the working time of bound materials based on dry density and unconfined compressive strength.
A brief description of the technical changes made are:
- Updated Table 1 to include additional terms and acronyms
- Clause 3 Heading changed to “equipment”
- Clause 4 Minimum sample mass increased
- Updated sample preparation procedure
- Clause 5 Updated testing procedure
- Clause 6 Updated calculations
- Clause 6.1 Removed reference to “maximum”
- Clause 7 Added reporting requirements
- Clause 8 Added references
- Added Figure 3 “workflow process”
General
- The test is performed on material passing the 19.0 mm ISO laboratory test sieve, with slow setting binders.
- Standard compaction must be utilised unless otherwise specified.
- Time limits will be required on testing.
Procedure
The procedure requires the optimum moisture content (OMC), maximum dry density (MDD), and unconfined compressive strength (UCS) for the mix to be determined at one hour after the addition of slow setting binder; the preparation of a bulk sample at this moisture condition and then UCS and dry density (DD) to be determined at subsequent time intervals in order to calculate the working time.
Through the revision process, the Test Method Review Committee are seeking additional feedback to support the current version. If you would like to contribute any proposed changes for review, please complete & return our spreadsheet form by COB Friday 2 September 2022.