What Is A Flexible Pavement In Civil Engineering
A flexible pavement is composed of a hot mix asphalt layer and an engineered foundation consisting of a base, subbase, and roadbed. Its purpose is to support axle and environmental loads.
What is flexible pavement?
Flexible pavement is a type of pavement made up of bituminous material surface with underlying base and subbase courses. It has a viscous nature that allows significant plastic deformation and is commonly built on a gravel base or directly on the subgrade.
What is the function of pavement?
Pavement is a durable surfacing used in civil engineering to transmit loads to the sub-base and underlying soil. Its primary function is to provide a stable surface for roads, airstrips or similar areas. Modern pavements contain bituminous material, such as asphalt, tar, or asphaltic oil, compacted with sand, gravel or crushed stone.
How do flexible pavement layers transmit compressive stresses to the lower layers?
Flexible pavement layers transmit vertical or compressive stresses to lower layers through grain transfer via contact points of granular structure. The maximum stress is on the pavement surface below the wheel load and is equal to contact pressure under wheels.
What type of CBR is used for flexible pavements?
The laboratory soaked CBR is generally used for the design of flexible pavements in areas where no prior information about pavement performance is available.
The flexible pavement comprises a hot-mix asphalt wearing surface of 4 inches, along with a soil cement base and crushed stone subbase of 10 inches each.
What are the different types of flexible pavement?
Flexible pavements used for California highways and roadways include various types of Asphalt Concrete, which is a combination of asphalt binder and graded aggregates, with aggregates ranging from coarse to fine particles. There are various formulations of flexible pavement that are used, each with unique characteristics.
What is hot mix asphalt (HMA)?
Hot mix asphalt (HMA) is a type of asphalt that is classified based on the temperature at which it is produced and applied. It is commonly used for flexible pavement construction and is designed to withstand heavy traffic loads and varying weather conditions.
What is cold mix asphalt?
Cold mix asphalt is an asphalt mixture that can be produced and applied at ambient temperatures, without the need for heating. It is often used for patching and repairing pavement, as well as for base course construction. Hot mix asphalt is the more common form of asphalt used for pavement construction, but cold mix asphalt provides a cost-effective and efficient alternative for certain applications.
What are the different types of HMA pavement?
There are different types of HMA (Hot Mix Asphalt) pavement, which vary in aggregate size, gradation, and asphalt binder content/type. However, the most common type in the U.S. is dense-graded HMA.
Flexible Pavements consist of bituminous or unbound material and transmit stress to the sub-grade through lateral distribution of applied load. This type of pavement is comprised of a bituminous material surface course and underlying base and subbase courses.
What is hot mix asphalt pavement?
Hot Mix Asphalt (HMA) pavement is a type of road surface made up of approximately 95% stone, sand, or gravel bound together by asphalt cement. This cement is created through a heating process that combines aggregate and is then mixed at a specialized facility.
What is rigid pavement?
Rigid pavement is a type of pavement that is constructed with a single layer and has the ability to transfer load in a wider range. It has good flexural strength compared to flexible pavement.
The California bearing ratio (CBR) value of a subgrade is considered essential in the design of flexible pavements, in accordance with IRC guidelines.
What is flexible pavement design by CBR method?
Flexible pavement design by CBR method is a process used to determine the total thickness of a pavement by calculating the California bearing ratio (CBR) value of the soil subgrade. This method can be carried out using one of two recommended methods: the CBR method recommended by California state highways, or the CBR method recommended by the Indian Roads Congress.
What does CBR stand for?
CBR stands for "California bearing ratio," which is a value used in the design of flexible pavements.
What are the advantages and disadvantages of the CBR method?
The CBR method has the advantage of being able to determine the thickness of pavement and individual layers as well as the subgrade soil, if the CBR-values of materials are known. However, it also has some disadvantages which are not mentioned in the question.
The main purpose of pavement is to transfer weight and pressure to the sub-base and soil underneath.
What is a metal pavement?
A metalled roadway is designed to handle vehicle traffic and is commonly found on frequently used roads. Flexible pavements are surfaced with bituminous materials and are called "flexible" because they bend or deflect due to traffic loads. A metal pavement is not mentioned in the article.
What is pavement made of?
Pavements are generally made of a combination of sand, gravel, crushed stone, and a binder of bituminous material (such as asphalt or tar) for flexible pavements, or of concrete made of aggregates and Portland cement for rigid pavements. The choice of materials depends on the specific requirements of the pavement.
Why should a road pavement be a good choice?
A road pavement should be a good choice because it provides a smooth and durable surface for all types of traffic while protecting the sub-grade soil from weathering. It should also be easy to construct and cost-effective.
