The equipment listed in Road and Highways consists mostly of equipment that is specifically used in the final stages of construction or in the maintenance of roads and highways. Many of the equipment models listed in earthmoving and mining are also used in road and highway construction. Examples of this are the scrapers, dozers, and loaders. Excavators are also commonly used in road and highway construction and are listed in the excavation and trenching section of this website.
The construction of road and highways basically consists of 3 phases, rough grading (or earthmoving), fine grading (which includes sub-grade preparation), and surfacing, which can include gravel, concrete, asphalt, or any combination of the three. Compaction is also a major element of all road and highway construction. Sufficient compaction of basic fill, gravels, and asphalt will ensure maximum life of the road structure. Operators must be capable of performing their work in a manner that will provide for maximum compaction. Operators who are involved in fine grading operations must be able to grade surfaces to very fine tolerances, requiring great skill as an operator.
This often includes changing the moisture level in the material being compacted. Machines may work to add moisture (water trucks and graders) or to reduce moisture levels (discs, mixers, graders, etc.). Paving using concrete or asphalt has evolved significantly over the years, and today’s machines can produce large quantities of paved surfaces in record time.
A drilling machine for quarry or opencast blasting, equipped with tracks and operated by independent air motors.
A chip spreader lays down the aggregate on top of a bituminous binder which is then rolled by a compactor.
A cold planer (also known as a pavement planer, pavement recycler, mill or asphalt milling machine) is a machine used to remove bituminous pavement or asphalt concrete from roadways, resulting in a somewhat rough, even surface that can be immediately opened to traffic. This is accomplished by bringing a rotating head into contact with the pavement at an exact depth or slope. The head, bites and tears away at the roadway surface. The surface material that is removed is fed by conveyor into a dump truck or can be left in place to be removed at a later date or recycled.
Vibratory roller compactor is used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. It is widely used to compress the surface being rolled to ensure a smooth, even surface. Vibratory rollers are widely used for compacting asphalt pavements because they achieve the required densities faster.
Pneumatic tire compactors are used on small to medium size compaction jobs, primarily on bladed, granular base materials. Pneumatics are not suited for high production, thick lift embankment compaction projects.
One advantage that pneumatic compactors have is that there is little bridging effect between the tires. Therefore, they seek out soft spots which may exist in the fill. For this reason, they are sometimes referred to as “proof” rollers.
Another advantage is that pneumatic rollers can be used on both soil and asphalt so a road building contractor can save by having one compactor for both stages of construction – base and asphalt.
Padded drum compactors are usually applied to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. The pads are involuted to walk out of the lift without fluffing the soil and tapered to help clean themselves.
A concrete plant, also known as a batch plant, is a plant that combines various ingredients to form concrete. Some of these inputs include sand, water, aggregate (rocks, gravel, etc.), fly ash, potash, and cement. There are two types of concrete plants: ready mix plants and central mix plants. A concrete plant can have a variety of parts and accessories, including but not limited to: mixers (either tilt-up or horizontal or in some cases both), cement batchers, aggregate batchers, conveyors, radial stackers, aggregate bins, cement bins, heaters, chillers, cement silos, batch plant controls, and dust collectors (to minimize environmental pollution).
The center of concrete batching plant is the mixer. There are three types of mixer, tilt, pan, and twin shaft mixer. The twin shaft mixer can ensure even mixture of concrete and large output, while the tilt mixer offers a consistent mix with much less maintenance labor and cost.
A curb machine takes concrete and creates a continuous curb and gutter.
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in rock ore), so that pieces of different composition can be differentiated.
Impact crushers involve the use of impact rather than pressure to crush material. The material is contained within a cage, with openings of the desired size to allow pulverized material to escape. This type of crusher is usually used with soft and non-abrasive material such as coal, seeds, limestone, gypsum or soft metallic ores. There are two types of impact crushers: horizontal shaft impactor and vertical shaft impactor.
A cone crusher breaks rock by squeezing the rock between an eccentrically gyrating spindle which is covered by a wear resistant mantle. As rock enters the top, it becomes wedged and squeezed between the mantle and the bowl. Large pieces are broken once, and then fall to a lower position where they are broken again. This process continues until the pieces are small enough to fall through the narrow opening at the bottom of the crusher. A cone crusher is suitable for crushing a variety of mid-hard and above mid-hard ores and rocks.
A jaw or toggle crusher consists of a set of vertical jaws, one jaw being fixed and the other being moved back and forth relative to it by a cam or pitman mechanism. The jaws are farther apart at the top than at the bottom, forming a tapered chute so that the material is crushed progressively smaller and smaller as it travels downward until it is small enough to escape from the bottom opening. The movement of the jaw can be quite small, since complete crushing is not performed in one stroke. The inertia required to crush the material is provided by a weighted flywheel that moves a shaft creating an eccentric motion that causes the closing of the gap.
A grader is a machine with a long blade used to create a flat surface. Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. In the construction of paved roads they are used to prepare the base course to create a wide flat surface for the asphalt to be placed on.
Asphalt distributors are used to apply prime or tack coats on a surface in preparation for paving. They are available in either truck mounted or trailer models and are considered the most important piece of equipment on any asphalt surface treatment project. It consists of an insulated tank with a heating system, a spray bar and unique control system.
Application of a prime or tack coat by the distributor is an exact science that requires sophisticated equipment to ensure it produces a uniform spray.
A paver (paver finisher, asphalt finisher, paving machine) is a machine used to lay asphalt on roadways. It is normally fed by a dump truck which brings hot asphalt.
An asphalt plant is used for the manufacture of asphalt, macadam and other forms of coated road stone, sometimes known as blacktop.
A cement mixer is a machine that homogeneously combines cement, aggregate (such as sand or gravel), and water to form concrete. A typical concrete mixer uses a revolving drum to mix the components.
Road Reclaimers, Mixers
Road reclaimers pulverize the asphalt layer and mix it with the underlying base to stabilize deteriorated roadways. The reclaimers can add asphalt emulsions or other binding agents during pulverization or during a separate mix pass.
Combination compactors are used for the compaction of asphalt base and sub-base courses for medium and large road construction and road maintenance. Some compact rollers also use a vibratory system on the front drum for density requirements and four pneumatic tires in the rear to provide impermeability and smoothness of the material. Compacted material manipulated by the four pneumatic tires helps in improving surface texture and reduce water intrusion.
One advantage of the padfoot is when the pad penetrates the top of the lift it breaks the natural bonds between the particles of cohesive soil and better compaction results.
Pull -Type Sheepsfoot
Pulled behind a machine, a sheepsfoot roller has almost hoof like structures protruding from a roller to offer pinpoint pressure as in a herd of sheep was walking across the field.
Today, vibratory compactors operated in the static mode are also used for finish rolling. In addition to their own weight, some steel wheel rollers can be ballasted with either sand or water to increase their weight.
The pneumatic tire roller is a self-propelled compaction device that uses pneumatic tires to compact the underlying surface. Pneumatic tire rollers employ a set of smooth (no tread) tires on each axle; typically four on one axle and five on the other. The tires on the front axle are aligned with the gaps between tires on the rear axel to give complete and uniform compaction coverage over the width of the roller.
Advantages of a pneumatic compactor is they provide a more uniform degree of compaction than steel wheel rollers. They provide a tighter, denser surface thus decreasing permeability of the layer. They provide increased density that many times cannot be obtained with steel wheeled rollers.
A truck used in winter to disperse sand onto icy roads.
A snowplow is a device intended for mounting on a vehicle which is used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes. A snowplow works by using a blade to push snow to the side or straight ahead, clearing it from a surface.
Modern street sweepers are equipped with water tanks and sprayers used to loosen particles and reduce dust. The brooms gather debris into a main collection area from which it is vacuumed and pumped into a collection bin or hopper.
A regenerative air street sweeper uses forced air to create a swirling effect inside a contained sweeping head and then uses the negative pressure on the suction side to place the road debris inside a hopper. Debris is removed from the air by centrifugal separation and reused, keeping particulate matter inside the hopper.
Water trucks are also in the construction industry which uses them for compaction and dust control.
Water wagons, usually converted scrapers, are an economical way to bring water.