The Average Least Dimension (ALD) of surfacing aggregates is required for the determination of the quantity of a bituminous product to be sprayed in the case of normal road surface treatments. The ALD is also needed for the calculation of the spread rate of surfacing aggregates. The accuracy of the measured ALD method TMH1-B18(a) (Technical Methods for Highways) depends on the sampling process, the sample size, measuring equipment, the interpretation of the least dimension, and the fraction of the sample not measured. The computational method TMH1-B18T(b), currently in use, is inaccurate and also does not take full account of the nature of the particle size distribution, which has   an effect on the estimated measured ALD.


  • Manual – Dial gauge, Foot piece & Stand
  • Standard – Complete ALD including Printer
  • Plus – Complete ALD, printer & Software

Laptop is not included













mm Reading                        – Displays the Actual millimetres.
Last Reading                       – Displays the last value.
Counter                               – Counts the number of reading taken.
Tare                                     – Zeros the mm Display.
Cancel Last Reading          – Removes the last value form the test average..Resets the Counter.
Test Complete                   –  Stop’s the test before 200 readings, should one choose to do so.
File Name                         –  Enter your Reference No/Name…On completion of the test, the results are save in a text format on the C Drive “C:Ald_Test_Results.”
Start                                  –  Starts a test, all previous data is erased…Requires a File Name.
Beep off                            –  Stops the Beeping sound after a reading has been taken.


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