Modification of Bitumens as a Method to Improve Performance

Performance of construction bitumens can be improved by upgrading the production technology or by introduction of special modifying additives. The first approach is necessary, but not sufficient to ensure that quality meets proper requirements.

One of the most important bitumen parameters is its operational range. This parameter can be characterized by interval of the so called plastic state, i.e. the difference between melting and brittleness points. In practice, this interval should be expanded by decreasing the setting point or raising the melting point.

This can be achieved by one of the following techniques:

  1. Obtaining of a mixture of high asphaltenic bitumens with products containing large amounts of low-molecular aromatic oils with having low viscosity and low setting point;
  2. Blowing bitumen with air;
  3. Oxidation in presence of phosphorus oxide or ferric chloride;
  4. Introduction of special substances (modifiers): polymers, plasticizers, structurizing agents, fillers, etc.

Fillers were the most popular additive for a time. They increased bitumen strength, but also reduced its elasticity and stretchability. Some of the most common fillers are:

  • kaolin;
  • asbestos;
  • technical carbon;
  • limestone;
  • talc.

Reduction of surface ageing rate can also be achieved by introduction of antioxidants, such as carbon black, into bitumen. Biological damage can be reduced by the introduction of biocides. Antipyrenes confer fire resistance to the bitumen compound.

Plasticizers are low molecular substances added to bitumen to reduce its viscosity. Besides, they raise cold endurance, water resistance and stretchability,  but reduce heat endurance at the same time.

Application of polymers can modify bitumen performance. In particular, there are such positive effects as improved flexibility, elasticity and durability in a wide range of temperatures. Styrene-butadiene polymers reduce bitumen sensitivity to extreme temperatures and considerably improve the quality compared with non-modified binders.

The UVB-2 plant produced by GlobeCore is a universal solution for bitumen modification using various additives: polymers, adhesive additives and plasticizers. The product comes with capacities from 4 m3/hour to 40 m3/hour.