ORIENTATION OF PARTICLES WITH SPECIAL REFERENCE TO BITUMINOUS PAVING MATERIALS
Geoffrey Lees, M. Salehi · Highway Research Record · 1969
A METHOD IS DESCRIBED FOR MEASURING PARTICLE ORIENTATION IN BITUMINOUS MIXTURES AND FOR ANALYZING THE DATA BY STATISTICAL TECHNIQUES TO DETERMINE THE EXISTENCE AND DEGREE OF PREFERRED ORIENTATION. SAMPLES PREPARED BY ALTERNATIVE LABORATORY COMPACTIVE PROCEDURES ARE COMPARED WITH EACH OTHER AND WITH THE COMPACTIVE EFFORT OF A FIELD ROLLER IN RESPECT TO THE DEGREE OF PREFERRED ORIENTATION. THE CONCLUSION IS DRAWN THAT FOR THE PARTICULAR MIX EXAMINED, GIVEN NUMBER OF PASSES OF A FIELD ROLLER CAN BE EQUATED WITH A CERTAIN NUMBER OF PASSES OF A LABORATORY ROLLER THAT ACHIEVES THE SAME DEGREE OF ORIENTATION. THIS STRUCTURAL ELEMENT OF THE FIELD SPECIMEN IS CONFIRMED TO BE MORE CLOSELY SIMULATED BY USING THE LABORATORY ROLLER FOR SPECIMEN COMPACTION THAN BY USING STATIC COMPACTION. THE RELATIONSHIP BETWEEN PREFERRED ORIENTATION AND SAMPLE ANISOTROPY AS REVEALED BY STRENGTH TESTS IN MUTUALLY PERPENDICULAR DIRECTIONS IS DISCUSSED. /AUTHOR/