ABSTRACT
There i s a great number of m a t e r i a l t e s t s i n existance showing a high, degree of t e c h n i c a l achievement and p r e c i s i o n . Such t e s t s are nevertheless not h e l p f u l l i n impro ving the mechanical p r o p e r t i e s of coated m a t e r i a l , as compaction under labo r a t o r y c o n d i t i o n s d i f f e r s g r e a t l y from compaction out s i d e . The specimens f o r these t e s t s must have the same p r o p e r t i e s as those of the ready com pacted l a y e r i n the f i e l d . Unfortunately formerly coated m a t e r i a l s being compacted i n the marshall compactor often have been c h a r a c t e r i z e d s t i f f e r than i n the r o l l e r com pacted layer i n the road. Moreover, the dimensions of the small marshall specimens are r e a l l y not s u i t a b l e f o r most of the important m a t e r i a l t e s t s . To avoid t h i s defect i t i s necessary to get knowledge about the d i f f e r e n c e between the compaction i n the labor a t o r y and i n the f i e l d such as the r e s u l t i n g mechanical p r o p e r t i e s of the asphalt con c r e t e . Therefore an extensive program of i n v e s t i g a t i o n was s t a r t e d comparing s y s t e m a t i c a l l y the mechanical pro p e r t i e s of cores taken from the road and specimens which have been prepared under laboratory c o n d i t i o n s .
