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Used in earth moving and levelling: equipment used in heavy construction, especially civil engineering projects, which often require the moving of millions of cubic meters of earth. The primary earth-moving machine is the heavy-duty TRACTOR, which, when fitted with endless tracks to grip the ground and with a large, movable blade attached in front, is called a bulldozer. Bulldozers are used to clear brush or debris, remove boulders, and level ground.

A scraper is a machine that may be pulled by a tractor or may be self-powered. It consists of a blade and a box or container. Dirt is scraped by the blade into the container; the dirt may then be released so as to form an even layer of a predetermined thickness, or be carried off for disposal elsewhere. Scrapers are used to level and contour land, as in road construction. Somewhat similar to scrapers are graders, self-propelled, wheeled machines with a long, inclined, vertically adjustable steel blade. Graders are primarily finishing equipment; they level earth already moved into position by bulldozers and scrapers. Lightweight tractors fitted with wheels in place of tracks are used for comparatively light construction jobs. Equipped with a backhoe, which is an open scoop attached rigidly to a hinged boom, such a vehicle can dig shallow trenches; equipped with a front-end loader, a scoop shovel affixed to the front of the tractor, it can lift and carry gravel, stone, sand, and other construction materials.

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Draglines and power shovels are the primary forms of excavation equipment. A dragline is fitted with an open scoop supported from the end of a long boom by a wire cable. The scoop is dragged along the ground by the cable until it is filled with earth, which is then dumped elsewhere. Draglines are used primarily to excavate deep holes. Power shovels are fitted with specially designed buckets called clamshells, which dig into the earth and shovel it up. The bottom of the clamshell can then be opened to dump the dirt into a truck for removal.

Scrapers A scraper is a machine that may be pulled by a tractor or may be self-powered. It consists of a blade and a box or container. Dirt is scraped by the blade into the container; the dirt may then be released so as to form an even layer of a predetermined thickness, or be carried off for disposal elsewhere. Scrapers are used to level and contour land, as in road construction. Somewhat similar to scrapers are graders, self-propelled, wheeled machines with a long, inclined, vertically adjustable steel blade. Graders are primarily finishing equipment; they level earth already moved into position by bulldozers and scrapers. Lightweight tractors fitted with wheels in place of tracks are used for comparatively light construction jobs. Equipped with a backhoe, which is an open scoop attached rigidly to a hinged boom, such a vehicle can dig shallow trenches; equipped with a front-end loader, a scoop shovel affixed to the front of the tractor, it can lift and carry gravel, stone, sand, and other construction materials.

Concrete Mixers

Most people recognise a concrete mixer as the hand loaded, rotating drum type designed to produce both concrete and mortar without segregation of the mix. The normal process of concrete production is to add water to the rotating drum, followed by the cement and then finally the concrete aggregate material such as gravel. If the mix is for mortar then sand is substituted in place of the aggregate. The actual choice of mixer will depend on the nature of the project. The following factors need to be taken into consideration when making the selection:

The maximum output required

The total output required

The type of material being mixed

The methods of transporting the completed mix

The discharge height of the mixer

The location of the mixer relative to the place that the mix is needed

The sequence of work

The number of gangs requiring mixes from the mixer

Generally for hand fed batches from a mixer a rule of thumb is to allow 5 to 8 minutes per batch cycle this is approximately 10 to 12 batches per hour. The following questions must always be in the back of your mind How much concrete is required? How much concrete can be placed? How much time is needed what mixing and what placing methods are to the used Small batch mixers: these are the ubiquitous diesel and electric small output, 200 litres per batch variety, often used with wheel barrows for transportation and hand laid. Most of these varieties are either a tilting drum type or even a small electric mixer. They can cost as little as �200. Care is required with the mixes from this type of equipment to ensure good quality control of both single and successive mixes to ensure a consistent mix design.

Tractor Shovels Combined loader/back actor: These are commonly known as the JCB, after the manufacturer – J C Bamford. They are actually manufactured by a number of companies, such as CASE. Lightweight tractors fitted with wheels in place of tracks are used for comparatively light construction jobs. Equipped with a backhoe, which is an open scoop attached rigidly to a hinged boom, such a vehicle can dig shallow trenches; equipped with a front-end loader, a scoop shovel affixed to the front of the tractor, it can lift and carry gravel, stone, sand, and other construction materials.

Background: The primary earth-moving machine is the heavy-duty tractor which, when fitted with endless tracks to grip the ground and with a large, movable blade attached in front, is called a bulldozer. Bulldozers are used to clear brush or debris, remove boulders, and level ground. A scraper is a machine that may be pulled by a tractor or may be self-powered. It consists of a blade and a box or container. Dirt is scraped by the blade into the container; the dirt may then be released so as to form an even layer of a predetermined thickness, or be carried off for disposal elsewhere. Scrapers are used to level and contour land, as in road construction. Somewhat similar to scrapers are graders, self-propelled, wheeled machines with a long, inclined, vertically adjustable steel blade. Graders are primarily finishing equipment; they level earth already moved into position by bulldozers and scrapers.

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