Paver (vehicle)

An asphalt pavers or paver is a machine that can be produced with the unbound and bound layers such as sand, gravel, asphalt and concrete. In addition to conventional machines also special forms have been developed that are tailored to a particular installation method (such as the compact asphalt paver ). A distinction is made between the track and the wheel asphalt paver. In common parlance the term or short pavers paver has prevailed for this type of machine. Commonly, the term is incorrectly used paving machine.

• 3.1 compact asphalt paver
• 3.2 Spray Paver
• 3.3 Ready with integrated spreader

Working environment

Pavers are used by the construction industry in all areas and are in the streets and roads, embankments and landfill and occasionally also in gardening and landscaping or track construction to find. In addition to the main task, the installation of rolled asphalt, sand, gravel, water- bound base and concrete can be installed to profile with the machine also. Machine installation of mastic asphalt is only possible with a mastic asphalt screed.

In the classical method of installation, the horizontal installations, the material to be incorporated is supplied by a dumper truck with no gear engaged, in a special front mounted bracket ( Abdrückbalken ) is pushed out of the machine. When installing on gradients, such as may occur during landfill construction and hydraulic engineering, are conventional variants or modifications in the form of a slope paver for use are available. Other application profiles are built- in skew or the production of PVC Windows and gauge railways in the track and landscaping.

As a rule, the pre-compressed material behind the machine is compacted and smoothed further by rolling. Depending on the construction tenders and method of use of a feeder may be required. Originally developed for the compact asphalt paver machine is used as a non-contact connecting element to the Mischguttransportfahrzeugen and uses a conveyor for material transfer.

Construction

The components of a paver consist of the drive, the material container ( receptacle ), the scratch tapes, auger, screed, heating and Nivillierautomatik. The material transport and distribution in the machine is automated and it can be overridden if necessary by hand. The basic structure of the machine is always the same, but may vary depending on the manufacturer in details such as usability and design of the various components.

The built quality of the paver is always dependent on the condition of the subgrade or the subsoil, the incorporated material, the mounting strength of the installation width, installation speed, the degree of wear of the screed and the asphalt paving in addition to the mix temperature as well as the meteorological conditions and the material template front of the screed.

Traction drive

The drive system of the machine consists of either chains or wheels; However, the majority are chain driven pavers ( paving speed 0-29 m / min) to see (also recommended from 6.50 m working width). The tracked pavers have better traction and are therefore well suited for large paving widths (up to 16 m). Tyred, however, are more mobile and allow a higher installation speed ( 0 - 40 m / min); they are also easier to implement by the Wheel of a construction site to the next ( self drive - no low loader necessary).

Pavers in the United States, notwithstanding equipped with high-speed chain drives ( fast running) and thus differ fundamentally from European models.

As engine used diesel engines from different manufacturers with a power range of about 33 kW to 259 kW.

Material container, conveyors and augers

The material container of the paver is located at the front and is used to hold the incorporated material. The capacity is depending on the size of the machine between 5 t and 14 t, which can be increased by material container inserts on average 20 t. The side walls are hydraulically retractable and allow complete emptying.

Further transport is taken over by a forward and backward running conveyors, which can be controlled independently depending on the number. Depending on the size of the model used are one or two available. With them, the material is transported through the machine in the auger chamber.

The uniform distribution of the material in front of the screed is obtained by two rotating conveyor screws. The independent snails can be extended depending on the installation width with corresponding parts. The pedestal is adjustable in height and can be adapted to the various paving thicknesses. Like the scratch tape, the snails are reversed.

Screed

The pavers differ over other construction machinery, such as caterpillars or graders, let by their floating screed, with the decrease in the substructure small bumps when driving without interfering with the control or balance. Its task is to compress the mix over the entire installation width evenly and create a closed, planar structure. Basically, a distinction is made between Rigid and Extending. All planks come in the middle by a mechanical or hydraulic roof profile adjustment. The dimension without extension or add-on parts is called the basic width or base screed.

The dead weight of the screed and the screed's compacting systems to produce the greatest possible pre-compression, so that different paving thicknesses have a small influence on the Walzmaß in the final compaction. During installation of the pile is connected to only two tow points of the machine. It is borne exclusively by the built-in material. Height changes are achieved by changing the angle of attack. The cylinder for lifting and lowering is without function, but can be selectively activated for some manufacturers to relieve the screed at nichttragendem material and thus achieve a higher mounting strength. A screed lock, however, is standard and allows after holding with float position, a start-up, without the Bohle changed their height.

If asphalt installed, temperature and composition of the material have greater influence on the behavior of the screed. Thus causes a high temperature an upgrade, while colder material, the screed can fall. The different types of asphalt and the addition of recycling also affect the viability and thus the installation strength. To prevent sticking of the asphalt, the screed can be heated electrically according to the manufacturer, or with gas.

If the screed broadened by attachments, are pre-stripper and Kanalleitbleche available. These are necessary in order to achieve a uniform mix in when paving widths and to prevent segregation of the material.

For compression, different units are available. The names are:

Nivillierautomatik

Basically Paver can be installed without assistance in specific layer thicknesses. Driving by "strength" is usually applied when the ground permits a uniform incorporation. To compensate for unevenness or greater to follow a pre-determined profile, are different methods available. The designation and technology used here varies depending on the manufacturer.

In normal case, the predetermined height is taken from a wire left and right and implemented by the actuation of Nivillierzylinder in elevation and slope. For one-sided scanning, the automatic has an inclination sensor on the plank, with the banks can be set. Furthermore, can be removed with the height sensors also curbs, gutters or directly from the ground. While in the 1990s were still mechanical height sensor in use, the ultrasonic scanner manufacturers offer in the 21st century, the balance through an internal filter unevenness in the floor.

Method with rotating laser, laser scanning of the subsurface, 3D control and combination of several ultrasonic sensors (Big MultiPlex Ski, Vögele or Big Sonic-Ski of MOBA ), the accuracy is further increased.

Special shapes

Over time, several special forms of asphalt paver were developed that were built specifically for new installation procedures.

Compact asphalt paver

The construction company Kirchner and Construction Brand Vögele developed in the 1990s, the compact asphalt paver to in one operation with a device " hot on hot " build the deck and binder. Kirchner built two modules that have been coupled with a commercial pavers in the Super 2500 series. However, problems in increasing the working width ultimately led to cooperation with Dynapac. Module 1 was a 45 t enlarged, self-supporting container material for asphalt binder. The second module included the technical part of the top layer paver and the power supply. The conveyors were replaced by screw conveyor. Another material for the cover layer container was mounted behind the first container. The two planks run the pre-compaction behind one another. The final density of both layers is done by roller in one operation. The augers take over alternately or simultaneously two feeder with conveyor belt. Compared to a conventional installation, in which the binder layer 8 cm and 4 cm top layer are strong, the thicknesses are the compact asphalt 10 cm and 2 cm. In the acquired Dynapac series production of the type was further developed and improved. The first production aircraft was based on the F300, which was supplemented by the construction module AM300 and used in 2004 by the company Bunte.

The company Vögele sets since 2007, notwithstanding her " InLine Pave " concept to standard sequential machines, which were slightly modified. The machine train consists of a feeder, the binder course with transfer module and the paver. In contrast to pavers Dynapac the paver moves to the pre-compacted binder course. An adhesion is prevented by wider floor plates on the tracked undercarriage and a water spray. And finisher binder have an increased material container, which is used in the standard receptacle. The machine hoist is equipped with a distance control.

A spray

A spray were developed to produce in the context of road repairs Thin layers in hot design on sealing (GSH -T) and apply the required binder with 200 g / m² to 1500 g / m² evenly. These include the pavers on a storage tank with sprayer for bitumen emulsion. The pattern offered by Dynapac provides one spray bar at the front and two jet nozzles behind the drive chains, so as not to damage the adhesive emulsion. The capacity of the tank is 2800 liters and is thermally insulated. Compared to the original Vögelevariante the screed and the spray system can be expanded by an attachment.

The solution offered by Vögele, upgrading conventional pavers with a SprayJet module has the standard tank 2000 l This can be extended by a tank used for the material container to another 5,000 l. The supply of mix is then made with feeder through a hopper directly onto the conveyors. Main tank and auxiliary tank are heated. A total of five spray bars are used, which are located behind the Abdrückbalken, left and right of the tracked undercarriage and front of the screed. The predecessor Super 1800 SF was equipped with a 4000 l tank. The maximum working width of 5 m was raised in the development of 6 m.

The rolling process of usually 2 cm thick asphalt layer is only static. A conventional installation with prespraying is also possible.

Ready with integrated spreader

By requesting a permanent grip on the road surface and the problems when sprinkling with rollers another type of paver was designed by Kirchner in cooperation with Demag. The idea behind the concept was a uniform asphalt paving and timely sprinkling with gravel. The attached to the tandem vibratory rollers spreader models and their problems of overlap ( material consumption ), high line load of the bandage, unwanted clustering, grit - free strips and too late introduction of Splittes, should thus be avoided. The problem of too much einsinkenden spreading material is too hot material and thus a fizzling of the effect on skid resistance should be compensated with bituminised grit (up to about 1% bitumen content ).

The prototype was completed by a chip spreader, of an installation width of 2.50 m covering without attachments to 5 m and ran behind the screed. With parts attached to extended the working width of 8 m. The supply of grit carried out with big bags on a transport device above the material hopper into a reservoir with 1.5 m³ capacity. Despite the advantages of a clean litter image and the application of clean gravel, this guy could not prevail.

Manufacturer

Known manufacturers of asphalt pavers are other Volvo Construction Equipment (Volvo CE, formerly Blaw -Knox ), and BOMAG ( Fayat group), Demag / Dynapac (Atlas Copco Group ) based in Wardenburg and founded in 1836, Joseph Vögele AG ( Wirtgen Group ). Companies such as Terex, Gehl Company and Caterpillar are represented mainly on the U.S. market.