Roads Corporation Victoria specifications for crushed rock aggregates for use in sprayed bituminous surfacing contain limits on particle size distribution and the allowable proportion of flat particles present in the aggregate. Flatness is defined in terms of the Flakiness Index test. This paper describes a study undertaken to assess the precision of the particle size distribution and Flakiness Index tests and of the derived Average Least Dimension value. It also reports the unexpected effect of the type of sieve shaker upon some testresults. The finding of major practical significance was that the precision of the Flakiness Index test is relatively poor. Hence producers must supply a product which has a true value substantially below the specified maximum value in order to have a high probability ofthe product being accepted. (A)
Abstract