Page 42 - Built Expressions - Online Construction Magazine - November 2014 Issue

Cover Feature lifted and forced down by hydraulic Road roller- Road rollers use the a steel wheel that has a number of steel rams. weight of the vehicle to compress the projections, or feet, welded to it. The surface being rolled. Initial compaction Sheepsfoot roller compacts the soil by 4. Bulldozers of the substrata is done using a kneading it. The feet on the roller can Bulldozer, which pushes earth and pneumatic tyred roller, with two rows sink through loose soil to a depth of rocks with a blade installed at the (front and back) of pneumatic tyres. approximately 10" (250 mm). These machine’s front end. Large- sized The fexibility of the tyres, with a rollers work best, therefore, when the crawler dozers normally have a set of certain amount of vertical movement lift thickness is between 6" and 10" (150 claws called a ripper that is installed at of the wheels, enables the roller to and 250 mm). Lifts of this thickness the machine’s rear end and can crush operate effectively on uneven ground. allow the feet to sink through the a hard rock. Swamp bulldozers are The fnish is done using metal-drum loose material and knead it into the lift equipped with an undercarriage that rollers to ensure a smooth, even result. below, while the smooth surface of the is confgured to enable them to freely There are different types of rollers wheel compacts the soil on the surface move around on a marshy land. As a available in the market based on the of the lift. As the lower portion of the fellow machine, there is a pipe- laying principle of compaction they adopt. lift becomes compacted, the feet ride machine that lays down a large steel Some of them are: Walk behind up into the upper portions of the lift pipe in the construction of a pipeline Rollers, Ride-on Rollers, Vibratory and compact it. Because of the manner and a dozer shovel (crawler loader) rollers, Pneumatic-tyre rollers, of compaction, it is best not to compact for loading. Tandem Rollers etc. Engineers have to a lift all the way to the top surface. By chose based on the nature of soil to be leaving the surface material loose, a 5. Rollers compacted. better bond will be achieved between Single Drum Vibratory Rollers- are that lift and the next lift that is placed. used to compact all types of soil Sheepsfoot Rollers Like steel-wheel rollers, sheepsfoot with the exception of rock fll. The These rollers are also called pad-foot rollers can be static or vibratory, and rollers are suitable for most types rollers. They are used to compact fne- come in several different models. of road construction, airfelds, dam grained soils such as clays and silts, The most common models are self- construction, harbour projects and as well as mixtures of sand and fne- propelled, tandem, four wheel, and industrial constructions. Heavy-size grained soils. The sheepsfoot roller is towed. In addition, some sheepsfoot vibratory rollers are used for a very rollers come with small bulldozer- wide range of applications. type blades, which allow the roller to perform rough grading or backflling as it compacts the soil. 6. Compactors Manually operated compactors have a number of different applications. They are used in areas where it is not possible to use a full size compactor. V November 2014vember 2014 PG 42 Vol: 3 Issue: 11ol: 3 Issue: 11 No PG 42 Built ExpressionsBuilt Expressions