Dispersion-Reinforced Semi-Rigid Materials Based on Asphalt Binders

Rehabilitation of deteriorated asphalt concrete pavements is an important task for the road industries in many countries. Roads built earlier with non-rigid road surfaces cannot cope with the growth of transportation load. Therefore, asphalt-cement composites of various compositions are widely used in the practice of road construction. In the article several variants of obtaining asphalt-cement composites are proposed. Several compositions based on asphalt granulate were selected for the experiment. Rubber crumb additive was introduced into bitumen in order to obtain an elastic transition zone due to the deformative properties of rubber particles reinforcing the asphalt binder. As reinforcement of the semi-rigid material, we used dispersed fibers of flax, cellulose and an additive in the form of a solution of polyvalent metal salts capable of creating additional structural bonds in the transition zone between the cement stone and the asphalt-binder. Experimental studies have shown a decrease in the angle of internal friction, which confirms the high stability of deformation without breaking the continuity of dispersed-reinforced material from asphalt granulate in a wide range of transport loads. Compositions with rubber crumb and linen fiber showed the best deformative qualities and resistance to repeated loads. The addition of crumb rubber modifies the bitumen film, and particles of undissolved rubber increase the elasticity of the material. Due to this, at rather large deformations (0.98 mm) and multiple loading, the stability of the samples is preserved (fracture work is 3.80 J). The introduction of linen fiber, which has high tensile strength and increased stiffness, allows to reinforce the transition layer in such a way that at sufficiently high strains (0.73 mm) and high work of destruction (2.69 J) the material remains stable. The resulting material can be used in load bearing areas.