Bitumen Types for Using in Road Construction
The surface course, base course, and sub base course are the three main tiers. Tack coat, binder course, and prime coat are the sub layers that are positioned between the major layers to bind them together. To shield the surface course from harm, protective Bitumen are also utilized.
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Binder Course
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Between the base course and the surface course is a binder course.
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It stops the surface from shifting and moving.
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Bitumen and coarse particles make up Binder Course's hot Bitumen.
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Due of the coarse stones, binder course Bitumen cannot be used for road and street surfaces. It contains less bitumen than surface course Bitumen does.
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The surface course, whose Bitumen contains significantly finer aggregates, should be applied over this layer.
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The hot Bitumen of the binder course can be made with various degrees of pure bitumen.
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Prime Coat
The surface of the base course is sandy. It is better to pour a thin layer of liquid bitumen on this surface before Bitumen it. This thin layer of liquid bitumen is called a prime coat.
Applying prime coat has several advantages:
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It seals the surface of base course
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It penetrates the pores of the base course. This causes that Bitumen adheres better to the base course
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Base Course
The base course has a sandy surface. Before paving over this surface, it is preferable to pour a thin layer of liquid bitumen upon it. Known as a prime coat, this liquid bitumen covering is thin.
Applying prime coat gives the following benefits:
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It seals the base course's surface.
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It gets inside the base course's pores. Bitumen sticks to the base course more effectively as a result.
Sub Base Course
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On the prepared bed pavement, the sub base course is often the first layer to be applied.
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It typically includes alluvial fans, mined rocks, and sediments from riverbeds.
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We can use chemicals, bitumen, and cement to stabilize the subbase soil.
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Good granulation is required in the materials we employ for the sub base layer.
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Fine particles from the subgrade layer cannot enter the subbase layer if the granulation is done properly.
Sub Grade
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The area of the ground known as the sub grade is where the base course, sub-base course, and Bitumen layers are laid. This layer must be extremely durable.
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The subgrade needs to be strong enough to withstand the loads that the pavement transfers.
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A good sub grade is one that can support loads for an extended period without bending or breaking.
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Protective Bitumen
In the construction of roads, protective Bitumen is typically employed as a temporary layer. It is not the primary part of the highway.
These layers are primarily employed to seal the Bitumen and stop the surface course from eroding.
The hot Bitumen must be used on protective Bitumen after three to five years. Because beyond this time the protective Bitumen's life expires and the primary layer of Bitumen may sustain long-term harm.
The primary benefit of protective Bitumen is their affordability. because liquid bitumen, which costs less than other types of bitumen, is the principal ingredient in these Bitumens.
Various Forms of Protective Bitumen, such as:
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Seal Coat
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Slurry Seal
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Chip Seal
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Micro Surfacing
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Fog Seal
There are many grades of Cut Back Bitumen and Emulsion Bitumen utilized in each of these Protective Bitumens.
Seal Coat
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A low-thickness protective Bitumen known as a seal coat is used to increase road tensile strength, shield the
surface from damage, and make it water-resistant.
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The emulsion bitumen types CSS-1, SS-1h, SS-l, and CSS-1 h can all be used for seal coating.
Slurry Seal
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Bitumen pavements are maintained via slurry sealing, which lessens the harm done by bitumen oxidation.
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Bitumen emulsion and cutbacks are the right form of bitumen for this kind of road maintenance. Slurry sealing can be done with SS-1, SS-h1, CSS-1, CSS-1h, and CQS-1h.
Chip Seal
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The major goal of placing a chip seal on an Bitumen surface is to shield the pavement from weather-related harm, such as heat and humidity from
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the sun. An emulsion with a rapid setting time that contains a CRS-2, RS-2, HFRS-2, and PMB is the best bitumen for chip sealing.
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Micro Surfacing
We can utilize polymer modified bitumen emulsion in micro surfacing protective Bitumen. We use SBS or poly bitex, two brand-new bitumen additives, in this sort of Bitumen.
Fog Seal
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Fog seal is a layer of Bitumen emulsion that guards against oxidation on roads and street surfaces.
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By adhering to the road surface as it dries and producing a durable coating, this kind of protective Bitumen lengthens the lifespan of pavements.
How Much Bitumen is Used to Build Roads?
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The width of the road and the thickness of the Bitumen both influence how much bitumen is used in the road surface
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But in general, for Bitumen with a thickness of 6 cm, the amount of bitumen per square meter is around 7 kg.
Why is bitumen used in the building of roads?
Bitumen is a powerful adhesive that can be used as glue to connect all of the hard aggregates. This material can withstand water and humidity well and has a high waterproofing characteristic.
How many layers of bitumen are there?
The surface course, tack coat, binder course, prime coat, base course, sub base course, and sub grade are among the bitumen road's seven layers.
