Study of Adhesion–Cohesive Interactions of Modified Bitumen Compositions

The aim of the work was to study the effect of additive concentration on changes in the adhesive and cohesive strength of bitumen. To evaluate the effectiveness of modifiers in the composition of binary and triple bitumen systems in relation to mineral fillers of two grades, the method of determination of the adhesive efficiency and thermodynamic calculations of adhesion and cohesion work were used. The following compounds were used as additives: AS-2 synthesized from the oil refining waste and AG-4I (waste sealing liquid). Adhesion–cohesion processes in modified bitumen systems are limited by the wetting effect of crushed stone and the intensity of intermolecular forces in the condensed phase of the binder. In the binary compositions, the addition of modifiers into bitumen significantly improves the cohesive strength and adhesive efficiency in relation to crushed stone. The introduction of AS-2 into bitumen compositions with AG-4I increases adhesion efficiency and thermodynamic work of adhesion in relation to the filler surface. The adhesion efficiency and thermodynamic work of adhesion in the “bitumen-AG-4I-AS-2” system reach their maximum at C_AG-4I = 3.0 g/dm³ and C_AS-2 = 1.5 g/dm³. In these concentration modes, the composition ensures maximum increase in adhesion efficiency (A_KS = 65.18%; A_KA = 48.11%) and the greatest increase in thermodynamic work of adhesion (W_A(KS) = 15.79 mN/m; W_A(KA) = 14.13 mN/m).