Description

SIGNUS, in collaboration with the department of Civil Engineering-Transport on the Polytechnic University of Madrid, has recently concluded an experimental development for the formulation and production of rubber modified bitumen under DOT criteria specified in the reference legislation enforced for roads. As a first step of the work, it has been identified all major reference binders in Spain, and after selection of the most and the less compatible to establish upper and lower limits of acceptance of powder in weight for different types binders, that is the range of aromaticity 76.3 % to 63.5 %. The experimental approach has been done with the most common granulometry for powder in Spain, 0-0,8mm, nevertheless there have been used two types of powder in Spain (high natural content 47%, and average natural content 38%) with relevant differences in behavior in the mix were they are used.

In this work it is given to the user of the guide the methodology to produce different categories of binder, which are:

Rubber Improved Bitumen (rubber: 10-11 %)
Polymer and Rubber Modified Bitumen ( rubber: + 4 -12%)
High Viscosity Asphalt Rubber with a high powder content (rubber: 18-22 %)

Moreover, it specifies the range of temperatures and digestion times to produce each category of product and the necessary quality control protocol to assure the compliance with DOT specifications.
In this work there is also a description on how the preliminary test should be done and what are the alternatives in equipments whether in laboratory and for the industrial scale, to achieve successful results.