Asphalt Paver (Paver Finisher): How It Works, Screed Width and Tracked vs Wheeled

How does an asphalt paver work?

An asphalt paver works like a moving funnel with a hot iron at the back. A tipper reverses up to the front and stops. The paver then pushes the tipper along on a pair of push rollers while the tipper body tips its load into the hopper, so the two travel together and the paver never has to stop for a new load.

From the hopper the mix follows the same path on every paver, whoever makes it. Wikipedia’s article on the paver describes it step by step:

1. The hopper, the open box at the front, holds the mix.
2. Slat conveyors, chains carrying flat steel bars, drag the mix along the floor of the machine to the back.
3. Two augers, large screws turning in opposite directions, spread it sideways across the full width and leave a small, even heap in front of the screed. Paving crews call this heap the head of material.
4. The screed, a heated steel plate pulled behind the machine on two long tow arms, rides on that heap, flattens it into a mat and gives it a first compaction with a tamper bar and vibrators.

The screed floats. Nothing bolts it at a fixed height. It finds its own level from the angle at which it meets the mix, its own weight, the push of the material in front of it and the pull of the tow arms. Because the tow arms are long, a bump under the tracks barely reaches the screed, and the mat comes out smoother than the base it was laid on.

The same floating action is the reason the operator has to hold two things steady: the paver’s speed and the size of the head. If the paver speeds up, or the heap grows, the screed climbs and the mat thickens. Slow down, or let the heap shrink, and the screed sinks and the mat gets thinner. Most paving faults start right there.

Figure 1: How mix travels through an asphalt paver

Parts shown in Figure 1:

1. Tipper bringing hot mix from the plant. It stops at the paver and is pushed along.
2. Push rollers, which take the tipper’s tyres without a jolt.
3. Hopper, which holds the load. Its side wings fold up to empty the corners.
4. Slat conveyor, which drags mix along the floor to the rear (the dashed arrow).
5. Augers, which spread mix across the full width.
6. Screed, which sets the thickness and smoothness and gives the first compaction.
7. Tow arm and tow point. Raising or lowering the tow point changes the screed’s angle and so the mat thickness.
8. Grade sensor, which reads the level from a reference and moves the tow point automatically.
9. Finished mat, ready for the breakdown roller.

What are the main parts of a paver finisher?

IRC:27-2009, the Indian Roads Congress specification for bituminous macadam, sets out what a paver finisher must have. Its annex asks for a loading hopper with a distributing mechanism, hydrostatic drive and control on all functions, a hydraulically extendable screed, tamping and vibration in the screed with adjustable amplitude and variable frequency, an electronic sensing device for automatic levelling and profile control, an internal heating arrangement in the screed, and a design that stops the tyres skidding or slipping while it works.

The table puts those parts in plain terms, with the figures from Ammann’s India range where the maker publishes them.

Hydrostatic means the engine drives hydraulic pumps, and oil from those pumps turns the wheels or tracks, the conveyors and the augers. The operator can then set any speed smoothly instead of stepping through gears, and a steady speed is what a smooth mat needs.

What is screed width, and how wide can a paver lay?

Screed width is the width of mat a paver lays in one pass. Every paver has a basic width, which is the screed fully pulled in and close to the width of the machine itself, and a maximum width it reaches with extensions. On Ammann’s India range the basic width is 2.5 to 3 m, and the maximum runs from 4.5 m on the WM 6 to 13 m on the ABG 8820.

A screed is made wider in one of two ways.

• Extending screed (also called telescopic or vario). Side sections slide out on hydraulic rams, and the operator can change the width while paving. That is what a road needs where it widens at a junction or narrows at a culvert. Vögele’s extending screeds cover widths from 0.25 m to 9.75 m across its range.
• Fixed screed. It is widened by bolting on extension pieces before the job starts, so it cannot change width on the move. In return it holds line and level across very wide mats. Vögele’s fixed screeds reach 18 m.

The MoRTH Specifications for Road and Bridge Works draw the line in the same place. Clause 406.3.4, for wet mix macadam laid by paver, asks for a hydraulically operated telescopic screed for paving widths up to 8.5 m and a fixed screed beyond that. IRC:27 asks that a paver be able to lay either 2.5 to 4.0 m or 4.0 to 7.0 m, whichever the contract states.

Match that to the roads you work on. IRC:73, the code for rural road geometry, allows an intermediate carriageway width of 5.5 m and keeps a two-lane road in hilly areas at 7.0 m. A paver that reaches 7 m lays that hill road in one pass with no joint down the middle. On a wider highway the contractor either runs two pavers side by side, which MoRTH clause 501.7.1 calls paving in echelon and which keeps the joint between them hot, or paves one lane and then the next and cuts and seals the cold joint as the same clause describes.

One limit is easy to miss. Vögele notes on its India pages that the maximum working width is limited by paving speed, type of material, layer thickness, material feed and site conditions. The top figure on a brochure is the most a machine can reach, not the width it lays well every day.

Figures are from the Ammann India and SANY India paver pages, read on 4 November 2026. Vögele’s India pages group its pavers into five classes, from the Mini Class (a MINI 500 lays 0.9 to 1.8 m at up to 20 t/h, for footpaths, cycle tracks and trench repairs) up to the Highway Class, where the SUPER 3000-3i lays up to 18 m at up to 1,800 t/h.

Tracked or wheeled paver: which one suits your work?

The undercarriage decides two things: how the paver moves between jobs, and how well it grips while it pushes a loaded tipper.

A wheeled paver is the common sight on Indian town and district roads. Ammann’s WM 6, AP 550 and AP 600 are all wheeled, with transport speeds of 15 to 17 km/h on their spec sheets. That lets a wheeled paver drive itself from one stretch to the next on a town job, and turn and reposition quickly on short runs, patch repairs and roads that keep changing width.

A tracked paver spreads its weight over two crawler tracks and keeps its grip on a loose or soft base. Ammann’s tracked models, the AP 1000 and the ABG 5420, 7920 and 8820, list transport speeds of only 3 to 3.6 km/h, so between sites they travel on a trailer. In return they carry the wide screeds and the high outputs. Every paver in Ammann’s India range that lays wider than 7 m is tracked, and the maker says the tracked AP 1000 was developed mainly for wet mix macadam (WMM), the crushed-stone layer laid under the bitumen.

Speeds and weights are from Ammann’s India spec sheets, November 2026. If most of your work is PMGSY and district roads a few kilometres apart, the wheeled paver’s self-drive saves a trailer trip on every move. If you lay long, wide highway packages and WMM, the tracked paver’s grip and width pay for the trailer.

Sensor paver or mechanical paver: what is the difference?

On Indian sites a sensor paver is a paver with automatic levelling, and a mechanical paver is one without it. Ammann sells both in India: it describes the WM 6 as a mechanical paver finisher, and the AP 550 and AP 600 as hydrostatic sensor pavers that come with one grade sensor and one slope sensor as standard.

A grade sensor reads height from a reference. That reference can be a ski that slides on the old surface or the kerb, a sonic sensor that bounces sound off it, or a tight string line set by the surveyor. A slope sensor holds the cross slope, the side-to-side tilt that lets rainwater run off the road, which is set by the camber in the drawings. The control box keeps raising and lowering the tow point so the screed follows the line and not the bumps in the base.

For national highway and other MoRTH-specification work, the sensor is required. Clause 501.5.3 says that, except in areas a paver cannot reach, bituminous materials shall be spread, levelled and tamped by an approved self-propelled paving machine equipped with an electronic sensing device, and that the paver finisher shall conform to Annex A of IRC:27. IRC:27 itself says the paver should preferably be equipped with a sensor. A mechanical paver can still lay well in skilled hands on smaller work, but read the specification clause in the contract before you bid with one.

How many tonnes an hour can a paver lay?

Maker output figures run from 150 to 200 t/h for Ammann’s WM 6 to 1,100 t/h for its ABG 8820, and up to 1,800 t/h for Vögele’s largest machine. Those are the most a paver can take in good conditions. On a real job the paver almost never sets the pace. The hot mix plant and the tipper fleet do.

MoRTH clause 501.5.3 says the rate of delivery to the paver shall be regulated so that the paver can work continuously. Every stop leaves a mark across the mat, so a paver that runs fast and then waits for the next tipper lays a worse road than one that crawls without stopping.

A worked example shows why. Take a 50 mm (5 cm) bituminous concrete layer, 7 m wide.

• Each metre of road needs 7 × 0.05 = 0.35 cubic metres of compacted mix.
• If the mix compacts to about 2.3 tonnes per cubic metre (your lab’s Marshall test gives the real figure for your job mix), that is about 0.8 tonnes of mix per metre of road.
• A plant sending 100 tonnes an hour therefore feeds about 125 m of road an hour, roughly 2 m a minute.

An Ammann AP 600 can pave at up to 40 m a minute, about twenty times faster than that plant can feed it. So set the paver’s speed to the plant, never the other way round, and add tippers until the hopper never runs empty. What it takes to set up and run the plant itself is covered in the guide to the hot mix plant business.

Which road layers does a paver lay?

A paver lays more than the black top. In the MoRTH specification it appears in several layers, each described in the guide to road construction layers:

• Bituminous layers such as bituminous macadam, dense bituminous macadam (DBM) and bituminous concrete (BC), under clause 501.5.3. Before the paver arrives the surface gets a prime coat or tack coat, and the binder is chosen by bitumen grade.
• Wet mix macadam, under clause 406.3.4, which allows a motor grader only in exceptional cases and with the Engineer’s prior approval. The other jobs a grader does on a road are set out in the guide to motor grader applications.
• Dry lean concrete, which clause 601.6.4 says shall be placed by a paver with an electronic sensor, unless the contract says otherwise.
• Cold mix, which clause 518.2.3.5 allows to be placed by a paver or a grader, as the contract specifies.

A concrete road’s top slab is a different matter. Pavement quality concrete goes down from a slip form or fixed form paver, a separate machine with its own moulds, vibrators and dowel inserter, explained in the guide to slip form paving.

The paver also has to stop where hand work takes over. MoRTH asks for hand laying by trained staff in confined spaces, on footways, in irregular shapes and at the approaches to expansion joints, and says machine laying shall stop 300 mm short of an expansion joint on a structure. Mix hotter than 145°C shall not be laid on a bridge deck’s waterproofing unless the Engineer approves precautions against heat damage.

Why does a paved mat come out wavy, torn or patchy?

A wavy, torn or patchy mat usually comes from something that changed at the paver: speed, the head of material, the screed temperature or a bump from the tipper. MoRTH 501.5.3 asks for an even, uniform flow of mix across the screed, free from dragging, tearing and segregation (separation of the coarse stone from the fines), and the table works backwards from what the crew sees.

Wikipedia’s article on the paver points to the tipper as a common culprit: when a dump truck fills the hopper it can make contact with the paver or change its speed, and that moves the screed. This is why large jobs use a material transfer vehicle between the trucks and the paver, so the paver is fed without being touched.

A failed surface months later is a different question from a bad mat on the day. Cracks, potholes and rutting in service are covered in the guide to pavement failure.

What machines work with an asphalt paver?

A paver is the middle of a train. In front of it the surface is cleaned, MoRTH clause 501.5.2 asking for a mechanical broom and an air jet from a compressor, and sprayed with tack coat. On an overlay, the old surface may first be cut by a milling machine, explained in the guide to cold milling. Behind it come at least three rolling stages, and MoRTH clause 501.6 sets the size of each:

Rollers run at no more than 5 km/h, the driven drum nearest the paver, and the longitudinal joint is rolled immediately behind the paving. The guides to the tandem roller and the pneumatic tyre roller explain how each one compacts.

Choosing the rollers for a paving crew? Compare tandem roller models and specs and pneumatic tyre rollers, or put two of the most-asked 9-tonne machines side by side in the Dynapac CC425 vs L&T 990HFi comparison.

The full list for a road package, from excavator to water tanker, is in the guide to the machinery required for road construction.

How do you choose an asphalt paver for your work?

Start from the road, not the brochure. Six questions settle most choices.

1. What width do you lay most often? Pick a paver whose everyday width sits inside its range, not at the very top of it. A 5.5 m intermediate road and a 7 m hill road need different machines from a four-lane highway.
2. Which layers will it lay? Bituminous layers suit any paver with a heated screed. If the work is mostly WMM or dry lean concrete, look at a tracked paver with the grip and output for stiff, heavy material.
3. Does the contract ask for a sensor paver? MoRTH-specification work does, under clause 501.5.3. A mechanical paver limits you to work that allows it.
4. How far apart are your jobs? Frequent short moves favour a wheeled paver that drives itself. Long packages favour a tracked one that goes on a trailer once.
5. What will your plant and tippers actually deliver? A 1,000 t/h paver fed by a 100 t/h plant works at a tenth of its capacity. Size the paver to the supply.
6. How is the screed heated, and who services it? Ammann fits diesel screed heating as standard on the AP 550 and gas heating as standard on the AP 600, with diesel as an option, and Vögele heats its fixed screeds electrically. Check that parts and a service engineer are within reach of your sites, and that you have a trained operator; pay and the route into the job are covered in the guide to the paver operator salary.

Makers with road pavers on their Indian websites in November 2026 include Ammann, whose range carries the Apollo-badged AP models alongside its ABG pavers, Vögele (part of the Wirtgen Group) and SANY. Read each maker’s own spec sheet for the model you are offered, and ask for the paving width and output at the thickness you lay, not just the brochure maximum.

The machines that work around the paver are where most contractors start. Browse the full range of road rollers and compactors and motor graders, and talk to a verified dealer. More on how Indian roads are designed and built sits in the road construction guide.

Sources

Paver finisher features are from IRC:27-2009, Specifications for Bituminous Macadam (first revision), clause 4.4.3 and Annex A (IRC:27-2009 on archive.org). Screed, spreading, rolling, joint, lean concrete and cold mix rules are from the MoRTH Specifications for Road and Bridge Works, fifth revision, clauses 406.3.4, 501.5.2, 501.5.3, 501.6, 501.7.1, 518.2.3.5 and 601.6.4 (MoRTH specifications, 5th revision). Carriageway widths are from IRC:73-2023, clause 4.2. How a paver and its floating screed work is from Wikipedia’s article on the paver (vehicle). Paver widths, outputs, weights, speeds, sensors and screed heating are from the Ammann India, SANY India and Vögele (Wirtgen Group India) paver and screed pages. All were read on 4 November 2026. Roller weights are from each machine’s listed specifications.

Prices, specifications and features are indicative, vary by variant, location and date, and should always be confirmed with the official OEM or authorised dealer before any purchase decision. DesiMachines is not liable for decisions taken on the basis of information that may have changed after publication.