ABSTRACT
Abstract Asphalt concretes on roads and bridges are compacted by r o l l e r s with and without v i b r a t i o n . The compaction of the asphalt mixes i n the laboratory i s i n general done by impact. The Marshall t e s t i s up to now the main c r i t e r i o n for the design of asphalt mixes i n many countries (e.g. Germany DIN 1996). Using a Proctor hammer d i s c s of 15 cm diameter of compacted asphalt can be produced which are s u i t a b l e for permeability t e s t s or for obtaining prisms for bending t e s t s . Depending on the composition of the asphalt mixes, the way of compaction has a d e c i s i v e influence on the properties of the mix. For the compaction of asphalt mixes a s t e e l r o l l e r with v i b r a t o r was constructed. The weight, the speed and the v i b r a t i n g force of the r o l l e r can be varied i n a wide range to achieve the required compaction. By exchanging the r o l l e r with two rubber-lined wheels r u t t i n g t e s t s can be performed. Keywords : Asphalt Mix, Compaction, V i b r a t i n g R o l l e r , Laboratory, Rutting
1 Introduction
The compaction of asphalt concretes on roads and bridges i s in general done by r o l l e r s with and without v i b r a t i o n . The work required for the complete compaction depends on the properties of the mix, the temperature and the thickness of the l a y e r . For laboratory t e s t i n g the compaction i s i n general performed by impact e.g. by the Marshall hammer as i t i s described i n DIN 1996. The Gyrator t e s t i s another method for determining the c o m p a c t i b i l i t y of an asphalt concrete mix /1,2/. The measure for the compaction i s the void content, e.g. determined according to DIN 1996. Depending on the composition of the asphalt mix, the way of compaction can have a d e c i s i v e influence on the properties of the mix. Figure 1 shows the p r i n c i p l e s of the compaction by the Marshall hammer i n comparison to a v i b r a t i n g r o l l e r . By the second method not only a v e r t i c a l but also a r o t a t i n g movement of the aggregate i s possible with i t ' s e f f e c t on
the compaction and the density of the mix.
