ABSTRACT
The mixture of materials has considerable internal friction properties as well as viscous flow properties which again are dependent on the temperature. If the material is produced by crushing, a considerable degree of control of the shape is possible. The best guide to the temperature at which a bituminous material should be laid is the viscosity of the binder in the mix. The quality of a bituminous road material is mainly determined at the mixing plant, there is close control of aggregates and of the binder – one of the more important points being the mixing temperature. The material in the heap, from which the sample is to be taken, is passed through a riffle box of a suitable size. Traditionally, mastic asphalt was a fluid, hand floated material, unsuitable for machine laying. Laid material will cool to the setting temperature in a very few minutes, thus limiting the time available for compaction.
