Bitumen Road

Bitumen is a black coloured sticky high viscous liquid or semi-solidified petroleum byproduct(e.g crude oil). It is also known as Asphalt. The asphalt is a mixture of aggregates(sand, stone or gravel) and bitumen for surfacing the road park with bituminous materials. The purpose of using asphalt for road construction is to bind the mixture of aggregate particles with each other such that it forms various layers. Such roads constructed using bitumen are called bitumen road. There are two types of bitumen road. They are: 

Bitumen road

Types of Bituminous Road

1.Bituminous penetration Macadam road

It applies the following steps for it’ construction:-

1.Preparation of existing layer

2.Spreading of coarse aggregate

3.Rolling

4.Applying bitumen binders

5.Seal the above coats

6. And give smooth and tough finishing

2.Bitumen carpet road:

It applies the following steps for it’ construction:-

1.Preparation of existing base

2.Applying a tack coat

3.Preparing and replacing the premix;(premix is prepared in the mechanical rotating mixer)

4.Rolling and finishing operations 

Types of Bitumin Road Surfaces

Bitumen road

1.Prime coat:

This is the primary single coat of low viscous bituminous binder applied on the already present base. It is applied to enhance the adhesion feature between given base and binder, to prevent from penetration of water surface through sealing effect and make the surface hard and tough.

2.Tack coat:

After prime coat, it is applied between bitumen or cement concrete base to improve sufficient binding property within surfaces.

3. Seal coat:

On the tack coat, there may be pores through which water can be absorbed that can cause bad impact on the compactness of binding materials so, to prevent from such problem we have to seal it. And the layer used for sealing is said to be Seal coat. Seal coat also helps to provide visibility of road during night time which may be a helpful hand in reducing the accident rate.

4. Surface dressing:

The phenomena for preparing base consisting of two or more coats of bituminous binding materials is known as Surface dressing. Spraying the prepared base over the seal coat and compressed by using rollers. It works as a waterproofing smooth surface that can be protected from various damages like cracks, ditches etc.

Determination of quality  of bituminous materials: 

To assess the properties of bituminous materials like its consistency, viscosity, graduation, temperature, susceptibility, and safety, the different test can be done in the laboratory. Some of the lab tests are as follow:

1.Penetration test

2.Float test

3.Ductility test

4.Softening point test

5.Specific gravity test

6.Viscosity test

7.Water content test

8.Loss on heating test

The procedure of bitumen road construction :

To construct the bituminous road, following steps which are already explained in the above-mentioned types of bituminous surfaces:-

1.covering the already existed base layer

2.providing the bond between the layers

3.sealing the pores available there in tack coat

4.through surface dressing, give hard and tough finishing

Merits and Demerits of bituminous materials for road construction:

Merits:

Economically, it is less expensive than concrete type road and as it is easily available in the nature for developing country it is good to use within low budget.

It provides sufficient binding property due to which up to certain time durability reamins.

Demerits: 

1.comparing with concrete pavement it has the low tensile strength

2.less durable than concrete pavement

3. Various nature disaster can easily affect the bituminous road

4. It can cause bad impact on human health causing various diseases like skin problem, lungs, etc. 

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