Roads play a major role in the economic development of a nation. Roads make a crucial contribution to economic development and growth and bring important social benefits. They are of vital importance in order to make a nation grow and develop. The Indian government is aiming for up gradation of its infrastructure mainly for road construction projects across the length and breadth of the country. Proposals and tenders for construction of National highways and local roads have been passed on the fast track. Many old projects too have been restarted to put the country on the path of development of world class infrastructure.
In case, you plan to start construction work or you are new to this industry with a road construction project in hand, then the first thing you should start with is the selection of construction equipment. Given below are few of the most used road construction equipment.
A motor grader, is a construction machine with a long blade used to create a flat surface during the grading process. Although the earliest models were towed behind horses or other powered equipment, most modern graders contain an engine, so are known, technically erroneously, as “motor graders”. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third axle at the front end of the vehicle, with the blade in between. Most motor graders drive the rear axles in tandem, but some also add front wheel drive to improve grading capability. Many graders also have optional attachments for the rear of the machine which can be ripper, scarifier, blade, or compactor.
A road roller (sometimes called a roller-compactor, or just roller) is a compactor-type engineering vehicle used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. Similar rollers are also used at landfills or in agriculture. Road rollers are frequently referred to as steamrollers, regardless of their method of propulsion. Road rollers use the weight of the vehicle to compress the surface being rolled (static) or use mechanical advantage (vibrating). Initial compaction of the substrate on a road project is done using a padfoot drum roller, which achieves higher compaction density due to the pads having less surface area. On large freeways, a four-wheel compactor with padfoot drum and a blade, such as a Caterpillar 815/825 series machine, would be used due to its high weight, speed, and the powerful pushing force to spread bulk material. On regional roads, a smaller single padfoot drum machine may be used.
Asphalt Mixing Plant
Asphalt Mixing Plant is another important road construction equipment. If the project is a large one, then the asphalt mixing plant is set on the road construction site. Hot mix asphalt material for paving is usually a mixture of graded, high quality different sizes of aggregates which are heated and mixed with liquid bitumen in measured quantities to produce hot mix asphalt. Asphalt is a paving material made out of crushed rocks and bitumen. Apart from the relative amounts and types of aggregate and recycled asphalt pavement used to produce hot mix asphalt, characteristics of hot mix asphalt is determined by the amount and grade of bitumen used while making the asphalt.Hot mix asphalt production requires drying and heating of aggregates so that bitumen can be coated easily. The drying process involves drying of the aggregates in rotating, slightly inclined dryer drum equipped with a burner. Aggregate is introduced in the higher end of the drum. Interior of the drum is equipped with different types of flights that help in properly heating the aggregates and also aid in properly coating it with bitumen.
A forklift (also called lift truck, jitney, fork truck, fork hoist, and forklift truck) is a powered industrial truck used to lift and move materials over short distances. Forklifts are rated for loads at a specified maximum weight and a specified forward center of gravity. An important aspect of forklift operation is that it must have rear-wheel steering. While this increases maneuverability in tight cornering situations, it differs from a driver’s traditional experience with other wheeled vehicles. While steering, as there is no caster action, it is unnecessary to apply the steering force to maintain a constant rate of turn.
Another critical characteristic of the forklift is its instability. The forklift and load must be considered a unit with a continually varying center of gravity with every movement of the load. A forklift must never negotiate a turn at speed with a raised load, where centrifugal and gravitational forces may combine to cause a disastrous tip-over accident. The forklift is designed with a load limit for the forks which is decreased with fork elevation and undercutting of the load (i.e., when a load does not butt against the fork “L”). A loading plate for loading reference is usually located on the forklift. A forklift should not be used as a personnel lift without the fitting of specific safety equipment, such as a “cherry picker” or “cage”.
A crawler excavator is a tracked vehicle designed to dig or grade, or move earth and large objects, and is classified by its mode of locomotion. The many types of excavators include wheeled, walker, towed and rail excavators. Related to tracked tanks widely used by armies, these crawlers move upon the same rotating wheel systems, but also have the ability to dig, pick and transport excavated materials as they proceed. Crawler excavators are widely used in construction work, such as digging trenches, holes and foundations, as well as for handling materials, moving earth, demolition, dredging, etc. Other attachments adapt the crawler excavator for boring, ripping, crushing, cutting and lifting.
A mobile crane is a cable-controlled crane mounted on crawlers or rubber-tired carriers or a hydraulic-powered crane with a telescoping boom mounted on truck-type carriers or as self-propelled models. They are designed to easily transport to a site and use different types of load and cargo with little or no setup or assembly. Mobile cranes generally operate a boom from the end of which a hook is suspended by wire rope and sheaves. The wire ropes are operated by whatever prime movers the designers have available, operating through a variety of transmissions. Steam engines, electric motors, and internal combustion engines (IC) have all been used. Older cranes’ transmissions tended to be clutches. This was later modified when using IC engines to match the steam engines’ “max torque at zero speed” characteristic by the addition of a hydrokinetic element culminating in controlled torque converters.
Wheel loaders are four-wheel-drive earthmoving machines used primarily to load loose materials with a front-mounted bucket. A lift-arm assembly raises and lowers the bucket. While mobility and enlarged bucket provide wheel loader high production output and add on high cycle times. The structural built up of wheel loaders is an added advantage. The articulated structure of the machine provides it with higher maneuverability in turning as compared to other wheeled and crawler excavation equipment with rigid chassis compelling it to work in confined areas. These machines are divided into two types: track mounted and tyre mounted.
Roads make a crucial contribution to economic development and growth and bring important social benefits. They are of vital importance in order to make a nation grow and develop. Choose wisely as per your project requirement. At the same time, one must keep in mind the changing jobsite requirements and application dynamics.