Scientific paper ID 1686 : 2018/3

Incorporation of shredded rubber particles into asphalt concrete mixtures is done by a wet or dry process. With the wet process, a range of highly modified viscous rubber modified binders is developed to non-agitated substances. There are three types of rubberized modified blends. The first type is a high viscosity wet process mixture that s stirring, while the second type is also obtained by a wet process but without agitation and with a viscosity close to the polymer-modified asphalts. The third type is obtained through a dry process.

The modified asphalt with rubber modifiers produced by the wet process is usually used for repair work with holes filling or sealing layer performance in existing flooring. The specifications that this product must meet are described in ASTM D6114. In this case, the crushed material is mixed with bitumen at higher temperatures, together with a polymeric modifier. The crushed rubber material is fully absorbed in bitumen and polymer without leaving visible rubber particles. Once the ingredients are mixed, continuous stirring is not d. Rubberized asphalt concrete finds various applications, including for spraying and hot mixes. In the wet process, the rubber powder is used as a bitumen modifier. The ideal particle size for wet methods ranges from 0.6mm to 0.15mm. Mixing rubber with bitumen should avoid unnecessarily high temperatures, as there is a risk of losing the positive properties of rubber.

The dry process refers to adding a rubber granulate to the mixture as a small part of the aggregate or filler rather than as a bitumen additive. This process is usually only applicable to handling hot mixes.

In the dry process or mixed in situ rubber-coated asphalt, the crushed rubber rubber material is mixed directly with the asphalt concrete mixture or added to the mineral components. Once the modifier is added to the hot asphalt mixture, it should be maintained at a temperature of 205 ° C to 220 ° C. Once the mixing process is complete, the temperature of the mixture should be maintained at 165 ° C to 220 ° C for a minimum of 45 minutes to 1 hour. This is important to ensure that the asphalt concrete is thoroughly mixed with the rubber material and in order to fully absorb the particles, which contributes to the high viscosity. Achieving a temperature higher than 2320C is a prerequisite for losing the positive properties of rubber. During this time other fillers, asphalt modifiers and / or comminuted rubber modifiers may be added, depending on the specific ments for the application material. It is important to note that, during mixing, the crushed rubber particles swell and various chemical reactions may occur. When the material is stable, it is ready for application. Generally, the high viscosity asphalt rubber contains approximately 18 to 22% rubber particles in the range of 2mm to 2.36mm.