In recent years there has been an increased interest in reducing the production temperature of hot mix asphalts. This has been achieved through different techniques: from production process modifications to the use of additives into de bitumen. In this work, the use of a special kind of chemical additives to achieve the production, laying down and compaction of asphalt mixtures at reduced temperature is studied. The chemical additives studied in this work, with the commercial name of Cecabase RT«, allow the production of an asphalt mixture at temperatures about 40?C (72?F) lower than a standard hot mix asphalt. They are liquid additives that are simply added into the bitumen at concentrations from 0.2 to 0.5 wt% with respect of bitumen. Observations suggest that the Cecabase RT« additives act at the mineral aggregate/bitumen interphase, in an analogous way to a surfactant that, as shown in this work, do not change significantly the bitumen rheological properties (viscosity or G*/sin d). The mechanical properties of warmmix asphalts done with a bitumen containing such additives have comparable properties to those made without additives at higher temperatures, as presented here in a series of laboratory tests. Examples of several field tests carried out with the Cecabase RT« additives under different types of bitumen and aggregates are also briefly presented. These examples include field tests with hard bitumens (penetration grade 10/20), reclaimed asphaltpavement and polymer modified bitumens.
Abstract