| Popis: |
One of the main reasons of low durability of asphalt concrete are the properties of bitumen which is the most sensitive of all its components to the action of external factors. As thermoplastic material, bitumen becomes soft at high summer temperatures leading to rutting, shear and sags formation. At low winter time temperatures it becomes fragile and rigid that due to low-temperature compression of asphalt pavement causes the occurrence of transverse cracks. The most effective direction for increasing the durability and roughness of asphalt pavement is changing the bitumen behavior by various types of additives modification. Among the issues related to all known modifiers, the least studied is the issue of using thermosetting polymers, namely, epoxy components. The main problem with the use of epoxy resins for modification is that under the influence of high process temperatures a rapid hardening of the epoxy resin after combining with the hardener occurs. Such behavior of epoxy components limits the temperature modes and the duration of process operations for the production, transportation and placement of epoxy asphalt mixtures. In this paper, the results of the study of epoxy-asphalt concrete obtained using the cut-back bitumen are presented. The dilution of bitumen allows reducing the process temperatures of the production of epoxy asphalt concrete mixtures which increases the time for their transportation and compaction. As a result of hardening of the epoxy resin, over time, a significant increase in the strength of the epoxy asphalt concrete occurs at all temperatures. The rate of hardening of epoxy asphalt depends on the temperature of the environment. As the temperature rises, the reaction rate between the epoxy resin and the hardener increases, which is reflected in the growth of the strength of the epoxy asphalt concrete at all test temperatures, the more intense evaporation of the solvent and, consequently, the growth of water saturation and the decrease in average density. Keywords. epoxy binder, epoxy asphalt concrete, epoxy resin, modification, cut-back bitumen. |
