Polymer Modified Bitumen
Modification of bitumen is one of the components of the integrated material production process during the construction and repair of roads, as well as the roof of buildings. Therefore, it is advisable to consider this issue in more detail.
What is bitumen. Scope of use
Bitumen is a black substance based on high molecular weight hydrocarbons and their derivatives, which is characterized by water insoluble. Resides in solid or resinous condition.
The origin of bitumen is natural and artificial. In the first case, the material is formed as a result of natural processes of oxidative polymerization of oil. And in the second, modern black gold processing processes are used.
The use of natural bitumen is known among the Assyrians and the Babylonians as far back as 3000 BC. Artificial bitumen was first obtained in 1898 from oil residues heated to a temperature of 300-320 ºС and oxidized by air.
At present, the basic industry in the use of petroleum bitumen is road and industrial construction (repair of roads and airfields, roofing, insulation of pipelines, production of paintwork materials).
In the road industry, bitumen is needed to bind the materials that form the road surface (sand, rubble, etc.), improve the hydrophobic properties and fill the voids. But in the course of operation, a number of negative factors affect bitumen: temperature differences, solar radiation, oxygen of the air, loads caused by heavy traffic. As a result, road surfaces prematurely lose their integrity due to the destruction of bitumen.
Bitumen as a building material:
- sensitive to changes in ambient temperature. In the heat it softens a lot, and in the cold it becomes brittle;
- has low elasticity and insufficient mechanical characteristics;
- subject to aging.
The properties of any substance, including road bitumen, can be improved in two different ways – by changing the production technology or by targeting the finished product. The first approach requires the restructuring of the entire system of obtaining materials, ranging from the preparation of raw materials to the type of equipment used. To do this at the same time and with minimal financial costs is impossible. Therefore, preference is given to the second approach, which is implemented through the polymer modified bitumen.
For the first time in practice, the technology of modification of bitumen was tested in the 30s of the last century in several countries of Western Europe. Small sections of roads are being opened, upon receipt of asphalt concrete paving which modified bitumen was used. The first modifier was natural rubber.