During the last few years the quality requirements on roads and railroads
have become more accentuated due to the desire to minimise maintenance
costs. This has, in turn, led to increasing requirements in the preparation
of ballast materials and pavement aggregates. As the access to natural
gravel in northern Europe is decreasing (due to lack of availability or by
law restrictions) the use of crushed rock material is becoming more and
more important. The aim of this paper is to derive and describe a universal method for
the prediction of particle size distributions from compressing crusher
machines such as jaw- and cone-crushers. Based on a closely defined
physical model, expressions which define the size reduction process are
derived. Conditions for simplifying assumptions are clearly outlined. The choice and mix of breakage functions is a central subtopic i the
analysis of the crusher machine processes. Known breakage functions are
reviewed and evaluated. A new concept for determination of a true
breakage operator which is related to physical properties of the crusher
device and the size distribution of the feed material is introduced. Finally experimental tests are compared to numerical calculations. The
method described in the paper can be a useful tool when designing
crushing plants or when optimizing the output of compressing crusher
Machines.