Asphalt and Bitumen: Types, Properties, Uses, and Comparative Analysis

What  Is Asphalt?

A mechanical mixture of inert mineral, say like, brownish alumina, lime, silica, etc. and the asphaltic bitumen. The colour is usually black or brownish-black. At low temperatures, it usually remains at soil but becomes liquid at a temperature of about 50° C to 100 ° C

Types of Asphalt

There two types of asphalt, namely.

1. Natural Asphalt
2. Residual Asphalt

1. Natural Asphalt

It occurs as fossil deposits in places like lakes Trinidad at a depth of  3 to 6m. It contains 40 % to 70 %  pure bitumen with about 30 percent contained.

2. Residual Asphalt

It is obtained from the distillation of petroleum oil with an aspheric base. The residue left will also be asphalt.

Forms of Asphalt

The usual forms of asphalt are as follows

1. Mastic Asphalt
2. Asphaltic Cement 
3. Cut- back Asphalt 
4. Asphaltic Emulsion

1. Mastic Asphalt

On heating the natural asphalt with sand and mineral fillers, mastic asphalt is produced. The resulting product is a void less impermeable mass. The hardness and melting point of mastic asphalt can be controlled during its manufacture. It may either be in a solid or semi-solid state.

But when heated to a suitable temperature it can be sufficiently fluid so as to be able to spread by a hand float. It is used as a material for damp-proofing and water-proofing.

2. Asphaltic Cement 

It is prepared by blowing air through melted asphalt at high temperatures. The asphalt is oxidized and the resulting product is plastic in nature and it is highly resistant to varying dimatic conditions. It is used for flooring, roofing, water-proofing, and filler in expansion joints in concrete.

3. Cut- Back Asphalt 

A liquid asphalt; prepared by dissolving asphalt in a volatile solvent. It can be applied at normal temperature in cold conditions. It is used for preparing bituminous paints, repairing roofs, etc.

4. Asphaltic Emulsion

It is produced by mixing asphalt with 50 to 60 percent water in the presence of 1 percent of the emulsifying agent. When water evaporates, the emulsion breaks and it forms a water-proofing layer. It can be applied in cold conditions.

Properties of Asphalt

Properties of asphalt are as follows:

1. A good insulation of electricity, heat, and sound
2. A tough and durable material.
3. A Water-proof material that can be elastic cleaned.
4. It is resilient and reasonably elastic.
5. It is non- inflammable and non-absorbent. 
6. It is not attacked by acids and is safe against vermin.

Uses of Asphalt

The asphalt is widely used for various engineering purposes. Some of the purposes are listed below:

1. As a water-proof layer for tanks, of roofs, basements, swimming pools, etc.
2. As damp-proof courses.
3. As flooring materials.
4. For preparing paints felt flashing.
5. For constricting roads and pavements, etc.
6. Taking of basement floors (building water barriers in basements)

What Is Bitumen?

The bitumen is the binding material that is present in asphalt. It also sometimes called mineral tar. It is obtained by partial distillation of crude petroleum. It is chemically a hydro-carbon. It is insoluble in water, but it completely dissolves in carbon disulfide chloroform, alkalies, alkaline, carbonates, petroleum spirit, and oil of turpentine.

It is found on analysis is composed of 87 percent carbon 11 percent and 2 percent oxygen by weight. The bitumen is back or brown in colour, and it is obtained is solid or semi-solid or sate. Its applications are the same as the residual asphalt.

Type of Bitumen

Following are the types of Bitumen

1. Blown Bitumen.
2. Cutback Bitumen.
3. Straight Run Bitumen.
4. Penetration Grade.
5. Bitumen Emulsion.
6. Residual Bitumen.

1. Blown Bitumen

Soft bitumen can be modified by heating until it becomes a liquid and then passing air under pressure by which all the volatile compounds in it can be driven out. The product is called blown bitumen.

2. Cutback Bitumen

Bitumen combined with other petroleum distillates forms cutback bitumen. This may be regarded as a means of applying penetration-grade bitumen at lower temperatures.

3. Straight Run Bitumen

When bitumen distilled to a definite viscosity of penetration, which does not require further treatment like heating.

4. Penetration Grade

The basic form of bitumen and has to be heated before application.

5. Bitumen Emulsion

A product in liquid form, formed in aqueous medium and stabilizing agents. This also another means to obtain bitumen into a liquid form so that it can be easily applied at ambient temperature.

6. Residual Bitumen

It consists of bitumen thinner and suitable filler made into a plastic Conn. As it is plastic, it can be used for filling cracks in masonry, stopping leakages, etc.

Use of Bitumen

1. Bitumen is used for the manufacture of roofing and damp proofing felts.
2. For sealing accumulators and batteries.
3. It also used for heat insulation materials for building, refrigeration, and cold storage.

Comparison Between Asphalt and Bitumen

FAQ: Asphalt and Bitumen

What Is Asphalt?

Asphalt is a mechanical mixture of inert minerals (like alumina, lime, and silica) and asphaltic bitumen. It typically appears black or brownish-black and is solid or semi-solid at low temperatures but becomes liquid between 50°C and 100°C.

What Are the Main Types of Asphalt?

The two main types of asphalt are:

1. Natural Asphalt: Found as fossil deposits in places like Trinidad, containing 40% to 70% pure bitumen.
2. Residual Asphalt: Obtained from the distillation of petroleum oil with an aspheric base.

What Are the Different Forms of Asphalt?

The common forms of asphalt include:

1. Mastic Asphalt: Produced by heating natural asphalt with sand and mineral fillers, used for damp-proofing and waterproofing.
2. Asphaltic Cement: Created by blowing air through melted asphalt, used for flooring, roofing, and water-proofing.
3. Cut-back Asphalt: Liquid asphalt dissolved in a volatile solvent, used for bituminous paints and roof repairs.
4. Asphaltic Emulsion: A mixture of asphalt and water with an emulsifying agent, used for cold application and forming waterproof layers.

What Are the Properties of Asphalt?

Asphalt is known for its:

1. Good insulation of electricity, heat, and sound
2. Toughness and durability
3. Water-proof and elastic nature
4. Resistance to acids and vermin
5. Non-flammability and non-absorbency

How Is Bitumen Related to Asphalt?

Bitumen is the binding material present in asphalt, also known as mineral tar. It is a hydrocarbon obtained from the partial distillation of crude petroleum and is crucial for forming asphalt.

What Are the Types of Bitumen?

Types of bitumen include:

1. Blown Bitumen: Soft bitumen modified by heating and air pressure.
2. Cutback Bitumen: Bitumen combined with petroleum distillates for application at lower temperatures.
3. Straight Run Bitumen: Distilled to a specific viscosity and penetration without further treatment.
4. Penetration Grade Bitumen: Basic form that requires heating before application.
5. Bitumen Emulsion: Liquid form created in an aqueous medium with stabilizing agents.
6. Residual Bitumen: Used for filling cracks and stopping leakages.

What Are the Main Uses of Asphalt?

Asphalt is widely used for:

1. Waterproofing tanks, roofs, basements, and swimming pools
2. Damp-proof courses
3. Flooring materials
4. Paint preparation and felt flashing
5. Road construction and pavement

What Are the Key Differences Between Asphalt and Bitumen?

1. Color: Asphalt is blackish-brown, while bitumen is dark with a reddish tint.
2. Carbon Content: Asphalt has lower carbon content compared to bitumen.
3. State: Asphalt can be solid or semi-solid, whereas bitumen is usually solid.
4. Heating Effects: Asphalt burns with smoke and flame, while bitumen melts.
5. Adhesive Power: Bitumen has higher adhesive power compared to asphalt.
6. Weather Resistance: Bitumen shows more resistance to weathering compared to asphalt.
7. Cost: Asphalt is typically more expensive to install than bitumen.

Can Asphalt and Bitumen Be Used in Extreme Temperatures?

1. Asphalt: Less sensitive to temperature changes, with negative impacts only in extreme conditions.
2. Bitumen: More susceptible to high temperatures, which can make it soft and slick.

How Do I Choose Between Asphalt and Bitumen for My Project?

Consider factors such as the application environment, temperature conditions, budget, and specific performance needs. Asphalt is often chosen for its durability in various conditions, while bitumen may be preferred for its weather resistance and cost-effectiveness.