Preparation and Properties of Modified Bitumen

Modern road construction places high demands on the quality of materials. This is especially true for the binders used in preparation of asphalt mixtures.

Pavements made from traditional bitumen can not cope with modern density and intensity of traffic.

Scientists assess the durability of pavements with bitumen-mineral composition, at only 50-70% of normative durability. Low elasticity, insufficient crack resistance and low temperature performance range restrict endurance of bitumen roads in hot summers and cold winters. These phenomena are especially evident in areas with sharply continental climate.

After much research it was found that one of the best ways to extend the life of asphalt pavement is to change the structure and properties of binder. This is achieved by modifying bitumen with polymer additives. With introduction of special substances bitumen receives a number of valuable properties, especially important in the road sector: resistance to aging and aggressive environments, toughness and elasticity. These characteristics do not change in above zero and subzero temperatures.

Special units are used to produce bitumen-polymer compositions. The production occurs as follows. First, materials are loaded into the unit separately. Bitumen is heated to 180°C and pumped into one of the mixers.

Polymers are delivered in sacks and loaded into the blender. Plasticizer is fed at the same time.

Usually, the unit can produce modified bitumen either with or without a plasticizer.

The components are dosed with flowmeters and adjusted by control system according to the formulation of the product.

Colloid mill crushes the pellets into fine particles and mixes them into bitumen.

Finished modified bitumen is pumped into bitumen storage tanks, or into containers for preparation of bituminous mastic.

Mixture of polymer modified bitumen is allowed to stabilize for 60 minutes, which is necessary for swelling of granules.

Offloading to customers or for in-house production is carried out directly from the storage tank. As for the mastic, it is poured directly into containers or packaging for storage of briquettes.

To produce the high quality polymer modified bitumen, GlobeCore developed the USB-3 unit.

The equipment has the following advantages:

• works perfectly with all polymers, waxes and various specific additives known to date;
• works with various forms of modifiers: powders, granules, etc .;can implement almost any type of bitumen modification;
• additional plasticizers and additives that improve bitumen adhesion can be added during pumping and modification;
• additional amount of polymer can be added when pumping;
• oil heating system can reduce costs.