What is HMA base course?

What is HMA base course?

Base course. This is the layer directly below the surface course and generally consists of aggregate (either stabilized or unstabilized) or HMA.

What is base course 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 9.5 mm asphalt used for?

A single course of 9.5 mm mixture is recommended due to the confined areas generally involved where constructing Sidewalk, Golf Cart Paths or Bike Paths except where poor subgrade is encountered.

What are the two types of base course?

Two types of base courses will be con- sidered in this paper, the fine a^regate type and the coarse aggregate type. The fine aggregate type material contains less than 35 percent of coarse aggregate (material re- tained on a No. 10 sieve) and the coarse aggregate type contains from 35 to 70 percent coarse aggregate.

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.

What is the purpose of base course?

Function of base course To act as the foundation of the road pavement and to transfer the traffic load safely to the sub base and sub grade. To withstand high shearing stresses due to the impact of traffic.

What is binder course?

Definition of binder course : a coarse aggregate bound with bitumen between the foundation and the wearing course of an asphalt pavement.

What is sub base and base course?

Base courses are usually constructed out of crushed aggregate or HMA. Subbase Course. The layer between the base course and subgrade. It functions primarily as structural support but it can also minimize the intrusion of fines from the subgrade into the pavement structure and improve drainage.

What is aggregate sub base course?

6.01 SCOPE: Aggregate Base and Subbase Course shall consist of natural or artificial mixtures of natural or crushed gravel, crushed stone or slag.

What is the use 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 VMA sand?

VMA Sand. An extremely fine, clean sand. Mainly used in asphalt production.

Why is VMA important in HMA?

– Adequate VMA is needed to ensure that adequate amount of asphalt could be added to the mixture without overfilling the voids and resulting in asphalt bleeding.

What is open grade asphalt?

Open Graded Asphalt is a porous asphalt mix formulated to provide large voids (in excess of 20 per cent) to allow surface water to drain away and hence increase safety for the motorist. The demand for low traffic noise surfacing has greatly increased in the last few years, especially in urban areas.