what is base course for roads

Full Answer

What is base course in road construction?

Base course. The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the wearing course and sometimes an extra binder course. If there is a sub-base course, the base course is constructed directly above this layer.

What is the base course made up of?

The Upper Base Course is made up of sand, gravel, and stone The Lower Base Course is made up of cheaply available material i-e rock and stone fragments 3.

What is the purpose of a base in a road?

It provides additional load distribution, contributes to drainage, uniform support to the pavement and a stable platform for construction equipment. Bases also help prevent sub grade soil movement due to slab pumping.

How thick is the base course of a road?

In roads and highways: Pavement The base course provides the required supplement to the strength, stiffness, and durability of the natural formation. Its thickness ranges from 4 inches (10 centimetres) for very light traffic and a good natural formation to more than 40 inches (100 centimetres) for heavy traffic and a…

What is the purpose of base course?

Under rigid pavements, the base course is used to: (1) provide uniform and stable support, (2) minimize damaging effects of frost action, (3) provide drainage, (4) prevent pumping of fine-grained soils at joints, (5) prevent volume change of the subgrade, (5) increase structural capacity of the pavement, and (6) ...

What is the meaning of base course?

Definition of base course 1a : the first or lowest course of a wall (as of a foundation wall or of the wall of a building above the basement) b : the bottom layer of material laid down in the construction of a pavement. 2 of a ship : a straight-line course the destroyer turned back to base course.

What is base course in asphalt?

The base course is the lower asphalt course (or courses), below the surface and any leveling course. The base course provides the strength of the pavement and typically has an aggregate top size of 3/4 to 1 inch. Tack / Prime Coat. The tack or prime coat is a spray applied application of emulsified asphalt.

What is the base layer of road?

The base layer forms the foundation for the road surface The bottom layer essentially comprises an unbound mixture of coarse and fine crushed stone, as well as crushed sand, to achieve the desired load-bearing capacity and absorb traffic loads so that the underlying subgrade is not deformed.

What is base course made of?

Base course is a layer of the pavement structure immediately beneath the surface course. It typically consists of high quality aggregate such as crushed gravel, crushed stone, or sand that provides a uniform foundation support and an adequate working platform for construction equipment.

Why is there a need for a base course in road construction?

The base course serves as a foundation for the paving. Depending on the stresses to be expected, the road comprises various layers of different thickness in order to withstand the most diverse weather conditions and remain serviceable for many decades.

What is the difference between subbase and base course?

A subbase is a layer of gravel or soil that comes over the subgrade. Over the subbase comes the base course layer. Subbase is considered the main load bearing layer of a pavement. Some of the subbase material used for construction are recycled concrete, granular fill.

How thick should base course be?

The base course is a compacted granular fill used to build up areas, set levels and provide a strong, stable layer to support the laid paver. Fill in the base course no thicker then 100mm and compact to a uniform dense condition, especially around manholes and kerbs (if more than 100mm is needed compact in layers).

What is base course in rigid pavement?

This is the layer directly below the PCC layer and generally consists of aggregate or stabilized sub-grade. It provides additional load distribution, contributes to drainage, uniform support to the pavement and a stable platform for construction equipment.

What is sub base?

Sub Base: It is layer of granular material provided above subgrade generally natural gravel. It is usually not provided on subgrade of good quality. It is also called granular subbase. a. Function of Sub base in Road Cross Section.

What is the term for the spread of bituminous binder over the roadway surface?

Thus is commonly called “Penetration Method”. Spread bituminous binder over the roadway surface then cover it with properly selected aggregate. This is commonly called the “Inverted Penetration Method”. Selections based on the requirements and economy, large volume of heavy vehicles, low traffic volume etc. 2.

What should subgrade material be?

The subgrade material should be clean and free from organic matter and should be able to be compacted by roller, to form stable sub-base. The material should have following characteristic.

Sub Base Course of Rigid Pavement

This is the layer (or layers) under the base layer. The properties and function of this layer are similar to those under flexible roads/pavements. A sub-base is not always needed and therefore may often be omitted.

Base Course of Rigid Pavement

This is the layer directly below the PCC layer and generally consists of aggregate or stabilized sub-grade.

Learn about this topic in these articles

The base course provides the required supplement to the strength, stiffness, and durability of the natural formation. Its thickness ranges from 4 inches (10 centimetres) for very light traffic and a good natural formation to more than 40 inches (100 centimetres) for heavy traffic and a…

road design

The base course provides the required supplement to the strength, stiffness, and durability of the natural formation. Its thickness ranges from 4 inches (10 centimetres) for very light traffic and a good natural formation to more than 40 inches (100 centimetres) for heavy traffic and a…

Examples of Base Course in a sentence

Place Asphalt Concrete Base Course, in lifts not exceeding 5.5 inches.

More Definitions of Base Course

Base Course means the crushed rock or aggregate which is placed immediately upon the sub -base course;

Related to Base Course

Core course means a course that a student admitted to a particular programme must successfully complete to receive the degree and which cannot be substituted by any other course

What is base course?

The base course is a layer or layers of specified or select material of designed thickness placed on a subbase or subgrade (if a subbase is not used) to provide a uniform and stable support for binder and surface courses.#N#The base course is the most important layer of a road structure which transfers the stresses developed due to traffic impacts through the wearing course. The base course layer provides the required foundation stiffness and structural strength.#N#Good quality crushed aggregates in line with technical specifications have to be used. If the crushed aggregate does no meet the required criteria it can be stabilised with Portland cement, lime, or asphalt. In the case of high-quality pavements, the crushed aggregates are treated with asphalt or Portland cement.

What is the purpose of a base course?

Function of base course 1 To act as the foundation of the road pavement and to transfer the traffic load safely to the sub base and sub grade. 2 To withstand high shearing stresses due to the impact of traffic. 3 To prevent the undesirable entry of sub grade soil in the pavement when the base course is constructed directly over the sub grade.

What is subgrade in paving?

The subgrade is the compacted natural soil below the pavement layers and it is the finished or compacted surface on which the pavement rests. They are also known as the formation and serves as the foundation of pavement layers.

What is the function of surface or wearing course?

The Function of surface or wearing course are as follows: To provide a smooth and uniform rigid surface. To resist the abrasive forces of traffic. To prevent dust nuisance. To act as a structural part of the pavement.

What are the components of a road?

A road structure consists of the following components: 1. Sub Grade: Subgrade is the foundation of the road, thus its the lowest and most important component of road structure.

What is sub grade material?

Material: Material of sub grade should be strong enough to bear the loads, easily accessible and available in the vicinity and cheap. 2. Sub Base: Consists of: Upper Base Course. Sub or Lower Base Course.

How high should a sub grade be?

If natural surface is below the formation level then the sub grade will be above the ground level. It should be constructed at least 60 cm (2ft) high from highest flood level of the area.

What is binder course?

Binder course layer is an intermediate layer between base course and surface layer. It is the first layer in case of two-layer bituminous resurfacing. Bituminous binder course is made of bituminous-aggregate mixture, also called as levelling course.

What are the different layers of bituminous pavement?

What are Different Layers in a Bituminous Pavement? Bituminous pavements are constructed in different layers such as base course, binder course and surface course. These layers are made of different materials and provides different functions to the bituminous pavements. 1.