Bitumen is what? Properties and area of application of bitumen

Bitumen is one of the most ancient building materials known to mankind. In our time, its use suggests quite a variety of options. There are many varieties of this material.

Varieties

Bituminous substances are organic materials, to which several species belong.

• Natural bitumen. It is a viscous substance or a solid material, which consists of compounds of carbohydrates and their derivatives. The ways of their formation are the natural oxidation processes of oil polymerization. They are widespread in the locations of oil. Pure natural bitumen is a fairly rare substance.
• Asphalt varieties. This type is found more often than the previous one. It is found in porous rocks. They are ground and powdered. So it turns out road bitumen.
• Oil. This is an artificial version of the material. It is obtained in the process of oil refining. In accordance with the type of technological cycle, such bitumens are divided into residual, oxidizing and cracking.

Composition

Bitumen has the following composition in the classical version:

• Up to 80% of carbon;
• Up to 15% hydrogen;
• From 2 to 9% of sulfur;
• Not more than 5% oxygen;
• From 0 to 2% of nitrogen.

The listed substances are in the form of compounds of hydrocarbons, sulfur, oxygen and nitrogen.

All elements can be classified into three groups.

1. A solid component is a high-molecular hydrocarbon, called asphaltenes. Paraffins also belong to the solid constituents.

2. Resins are amorphous materials that have a dark brown color.

3. Oil fractions are different hydrocarbons that have a density of less than 1.

Bitumen is a rather complex substance with a certain ratio of all components. An increase in its mass of asphaltenes will lead to an increase in hardness, brittleness and softening temperature.

Paraffins also reduce the plasticity of bitumen, so the production focuses on reducing their content to 5% or less.

Application area

Depending on the physical properties of the following directions of application of bitumen:

• Road construction;
• The device of a roof;
• Waterproofing;
• Manufacture of the cable;
• Tire-rubber technology;
• Accumulators;
• Varnish-and-paint products;
• metallurgy;
• Production of carbon fiber bricks;
• Oil refining.

In carrying out construction work on its own, bitumen is the most popular material for waterproofing various objects, especially cellars and cellars.

Oil road

Road construction uses bitumen petroleum road (GOST 22245-90). There are several brands of such material.

To properly choose a variety, you need to determine the type of climatic zone.

For natural conditions that are characterized by a temperature in the cold season on average not higher than -20 ° C, road bitumen such as BND 200/300, BND 130/200, and BND 90/130 will be suitable in accordance with GOST.

For regions where average temperatures in the cold season range from -10 to -20 ° C, bitumen road oil II and III climatic road zone is provided. These include the above varieties, as well as BND 60/90.

If the average monthly temperatures in the cold season are in the range from -5 to -10 ˚С, the GOST provides for the use of such oil road bitumen as all of the above types, as well as BND 40/60, BN 90/130, BN 130/200 , BN 200/300.

Petroleum road bitumens of such types as BND 40/60, BND 60/90, BND 90/130, BN 60/90, BN 90/130 are suitable for terrain in which winter is characterized by mean monthly temperatures of at least + 5 ° C.

Oil

There are varieties that are used to build not only roads, but also residential facilities. These are universal brands. There are only three brands, which include such oil bitumen as BN 70/30, BN 90/130, BN 50/50.

As well as bitumen oil road, GOST of which regulates the conditions of application of each variety, the construction bitumen is GOST 6671-76.

The lower the ambient temperature, the more elastic material should be used for construction. This will ensure its durability and durability of operation.

Oil roofing materials

For various works on the installation of the roof use a special bitumen. Properties and scope of its governing GOST 9548-74. This standard implies the use of three varieties of this roofing material:

• BNK 90/30 - has such a scope, such as the formation of the roof cover layer.
• BNK 40/180 - used for impregnation.
• BNK 45/190 - is chosen for the treatment of the roof and the production of material for the roof.

Factors affecting the type of road material

Bitumen road, GOST which provides for several types of such a substance, is characterized by a variety of different properties. Each gives certain qualities to the material.

The most important of them, determining the field of application of bitumen, are considered plasticity, softening temperature, brittleness, flashing, viscosity, adhesion qualities.

High temperatures increase the viscosity of bitumen. With cooling, the material loses this quality and at the time it reaches the thermal boundary becomes brittle.

Increase the plasticity helps to add to the composition of the material oils. The greater the frost resistance of petroleum road bitumen, the higher the grade of its quality.

Flash point is also a very important indicator for a material such as road bitumen. GOST provides a standard value of this parameter +200 ˚С and above. The higher the flashing temperature, the lower the fire hazard of the substance.

The indicator of adhesion will help to know how well the bitumen meets the base of the surface. The higher this index, the stronger the material holds on the surface.

Technology of material use

When building roads and other facilities, the technology of asphalt heating is applied. This process is carried out in accordance with certain rules. The technique of using the material lies in the characteristics of such a substance as bitumen. GOST discloses its most important properties.

To heat the material used in construction and repair, a special boiler with thick metal walls and a hermetically sealed cover is used. The thickness of the material will allow it to avoid burning.

2/3 of the capacity is filled. Bitumen is broken into small pieces before loading.

The heating is carried out on a small fire, and the material melts to a homogeneous mass. When foreign substances appear, they are extracted with a special screen. The limiting temperature of reheating is +200 ° C.

At a preheating temperature of +160 to +170 ° C, the bitumen melts in about 3 hours. If you increase it to the limit value, the heating process will be only 1 hour.

Petroleum bitumens do not tolerate an increase in heating above + 200 ° C, because their properties will deteriorate from this. At +220 ° C, coke will start to form.

If the bitumen is overheated, an unpleasant yellow-green smoke is produced, and when the boundary reaches +240 ° C, the substance can even flash. Then the boiler cover is closed to extinguish the flame.

After overheating and flare-up, the road bitumen becomes fragile and no longer suitable for construction or repair work.

Storage and transportation

The storage of bitumen occurs in special tanks. They are equipped with stirring mechanisms for the heated substance. This technique should have special ways of supplying water vapor to prevent flashing of the material.

To empty the reservoirs, they are provided with a bottom under the slope.

The technology, transporting liquid bitumen road, is equipped with special pumps that pump the substance.

If the material is transported in solid form, special demountable forms are used.

In the process of transportation and storage, all fire safety requirements are provided, since bitumen refers to highly flammable substances. Implementing all safety rules, you can not be afraid of the occurrence of unpredictable situations in working with this material. Having studied the properties and varieties of the material, it is possible to apply it competently in the construction of various objects.

Bitumen is a substance with such positive qualities as moisture resistance, strength, non-adherence to climatic influences, low sound and heat permeability, as well as low conductivity of the current. Due to these properties it is a very demanded and reliable building material.