Dependence of Physical and Mechanical Characteristics on the Specific Surface of Mineral Particles in Asphalt Concrete

Abstract

The ever-increasing intensity of traffic and axial loads from motor vehicles is forcing material scientists and road-building organizations to develop and use asphalt concrete with higher physical, mechanical and operational characteristics. An integral part, when creating new compositions of asphalt concrete mixtures, is the study of the processes going on at the phase boundary “surface of mineral particles - organic binder”.In the presented studies, mineral materials with different specific surfaces were considered. To study the effect of the specific surface on the physical and mechanical properties of asphalt concrete, the following were used: natural sand, quartz sand, and waste foundry sand. To obtain an objective result of the study, all materials were selected with the same size modulus. The first stage of laboratory research was aimed at studying the structure and surface shape of the particles of stone materials. The second stage consisted of molding asphalt concrete samples and determining their physical and mechanical characteristics. Three compositions of asphalt concrete have been studied.The presented studies confirm the theory put forward earlier by the authors about the mechanism of interaction of the surface of mineral particles with an organic binder. An increase in the specific surface of stone materials increases the adhesion force of bitumen to the surface of stone materials. It has been established that a well-developed, rough surface of particles of mineral aggregate in asphalt concrete can act as an effective modifying element. An increase or decrease in the specific surface area of the particles of mineral aggregate, with the same modulus of fineness, it is possible to achieve a proportional change in the strength characteristics of asphalt concrete using bitumen. With an increase in the specific surface of the particles of mineral aggregate in the asphalt mix, it is possible to create asphalt concrete capable of resisting increasing loads from the rolling stock.