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Unlock the Secrets of Dense Graded Hot Mix Asphalt: The Ultimate Guide for Street and Highway Construction

Alex Foster

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Published in An Introduction To Dense Graded Hot Mix Asphalt Pavement (Street And Highway Engineering)

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Asphalt pavements are a ubiquitous feature of modern transportation infrastructure, providing smooth and durable surfaces for everything from highways to parking lots. Among the various types of asphalt pavements available, dense graded hot mix asphalt (DGHMA) stands out for its exceptional performance and versatility. This comprehensive article will delve into the world of DGHMA, exploring its composition, properties, and applications while providing practical insights into its design, construction, and maintenance.

Composition of DGHMA

At its core, DGHMA is a composite material composed of a mixture of aggregate, asphalt binder, and air. The aggregate, typically crushed stone or sand, provides the structural strength of the pavement while the asphalt binder holds the particles together and imparts flexibility. The air content, carefully controlled during the mixing process, influences the overall density and performance of the DGHMA.

An Introduction to Dense Graded Hot Mix Asphalt Pavement (Street and Highway Engineering)

by J. Paul Guyer

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Language	:	English
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Properties of DGHMA

DGHMA possesses a unique combination of properties that make it ideal for a wide range of paving applications. Some of its key characteristics include:

High Density: With a typical density of 92-96% of the theoretical maximum density, DGHMA provides a dense and impermeable surface that resists moisture penetration and minimizes deformation.
Excellent Stability: The closely packed aggregate structure and the strong bond between the asphalt binder and aggregate particles result in exceptional stability, ensuring resistance to rutting and shoving under heavy traffic loads.
Flexibility: Despite its high density, DGHMA exhibits a degree of flexibility that allows it to withstand thermal expansion and contraction without cracking.
Durability: Properly designed and constructed DGHMA pavements can last for decades, with minimal maintenance requirements.

Applications of DGHMA

The versatility of DGHMA makes it suitable for a diverse range of paving applications, including:

Highways: DGHMA is widely used on highways and interstate roads, where its high stability and durability can withstand heavy truck traffic and extreme weather conditions.
Streets: The dense, impermeable nature of DGHMA makes it an ideal choice for urban streets, providing a smooth and quiet riding surface.
Parking Lots: DGHMA's resistance to rutting and shoving makes it well-suited for parking lots, which experience frequent vehicle movement and turning.
Airports: The durability and flexibility of DGHMA make it suitable for airport runways and taxiways, where it can handle heavy aircraft loads and thermal stresses.

Design and Construction of DGHMA Pavements

The design and construction of DGHMA pavements require careful consideration of several key factors, including:

Aggregate Selection

The selection of aggregate is crucial for the performance of DGHMA. The aggregate should be clean, durable, and have a suitable gradation to ensure proper compaction and stability.

Asphalt Binder Selection

The grade of asphalt binder used in DGHMA depends on the anticipated traffic loads, climate, and pavement design criteria. The binder must provide adequate adhesion to the aggregate and maintain flexibility under varying temperatures.

Mix Design

The mix design process involves determining the optimal proportions of aggregate, asphalt binder, and air to achieve the desired performance characteristics. This process is typically performed in a laboratory setting, where various mix designs are evaluated and tested.