Innovations in concrete paving technology

Paving with concrete offers a strong and long life base for a roadway, with manufacturers continuing to develop technologies  – Mike Woof reports

Innovation comes fast in the concrete paving market with a number of specialist suppliers offering an array of solutions to meet the needs of slipforming contractors. These machines can be used for a range of applications from large-scale airport runway or highway construction duties, tunnel jobs, bridge decks, barriers, traffic islands and kerbs. Because the application range is so diverse, the machines also range widely in design and configuration. There are smaller units designed to handle a range of jobs and larger and units for more specific duties. Control technologies have also advanced noticeably, with sophisticated guidance systems now offering efficient alternatives to conventional stringlines. 265 Leica Geosystems has pioneered alternatives to stringlines with its control packages, although both 2122 Trimble and 342 Topcon now offer systems for use with concrete slipformers while one manufacturer, Wirtgen, has even developed its own in-house alternative.

Based in Ida Grove, Iowa, 218 Gomaco offers an extremely diverse array of concrete slipformers. The firm’s recently introduced 4400 barrier machine has been designed to provide versatility for contractors, and for example it can be used for both right-side and left-side slipforming. The new machine was developed specifically for use in barrier applications and is also said to offer maximum operator comfort and visibility. Meanwhile ease of operation is provided by the firm’s well-proven proprietary G+ control system, which comes with multiple language capabilities. GOMACO engineers built the new 4400 around the design concept of a left-side and right-side slipforming capable machine with symmetrical steering and minimal set-up changes for switching profiles from side-to-side.

Its U-shaped operator’s platform, with vibration isolation and sliding control console allow quick changes from right-side to left-side pours and provide a 360° view of the paving operation. The 4400 features a 74kW 196 Cummins QSB3.3 diesel with a high-capacity cooling package, designed for noise reduction, is said to provide one of the quietest working platforms in the industry. The new G+ control system co-ordinates the speed of the hydraulic fan with engine and hydraulic oil temperature. The tractive system features a very low speed, allowing for the minimum speed and smooth crawl features for forming a vertical wall.

The new G+ speed dial turns to adjust in 1% increments and speed display feedback allows for smooth, precision paving speed control. The machine also has the new GOMACO Barrier Hook-and-Go mold mounting system. This means contractors can quickly mount barrier molds up to 1m tall on either side of the machine. An optional sidemount attachment is available for barrier taller than 1m or existing barrier molds, further increasing versatility. The barrier machine features the new 4400 series, 406mm diameter auger, designed specifically for transporting low-slump concrete.
Meanwhile other recent launches from GOMACO?include the GP-2400 slipformer with its compact paving dimensions.

Guntert & Zimmerman says that it is further extending the versatility of its S600 slipform paver with the introduction of the new ZeroKit. This is designed to allow paving operations in offset applications or where there is no clearance. Contractors can use the system along with the well-proven G&Z rigid paving package and the ZeroKit is designed to pave widths out to 3.6m. The company offers an A-Frame support that allows the standard paving kit to be cantilevered off either side of the S600 end bolsters, with or without using the extending TeleEnds.

The ZeroKit is suited for paving shoulders, ramps, and other pavements that require working up against a wall or barrier, but is only available on the S600 machine. The ZeroKit does not require any counterweight, so there is no need to equip an S600 with a barrier mold attached to the opposite side. The ZeroKit uses G&Z’s tractor frame and bolters, which feature a universal bolting pattern. This also means that the S600 can be converted from standard paving configuration to offset configuration with a 2-3 person crew in less than four hours. The steel A-Frame that provides the kit support is designed to prevent deflection and ensure a rigid pan. This A-Frame is fixed to the bolster using twelve standard bolts, while the ZeroKit is designed to fit onto either bolster without modification.

Meanwhile the firm has also upgraded its TeleEnd extension package to further boost versatility. Called the TeleEndXL, this new version offers an extension of 1.2m, compared with the 0.9m of the original TeleEnd unit. With two of the TeleEndXL units fitted to a machine, a contractor has up to 2.5m of quick adjustment capability available. Using the TeleEnds, a contractor can change the offset width in a matter of minutes and this option can also be used on all of the G&Z pavers.

3975 Power Pavers has based its SF1700 slipformer on the existing SF2700 machine, developing a more compact piece of equipment. This new two track unit can pave up to 7.5m wide, and was developed to meet demand from contractors for two-pass paving in many highway applications according to the firm. Demand is said to have been good for the unit since it was announced, with orders having been placed in various countries.

The frame of the SF-1700 is similar to the chassis used on the SF2700 from Power Paver. But by reducing the engine size and main frame width the firm says that it has made the new SF1700 more compact, providing an economical alternative for contractors desiring to pave highways in two passes.

The company has configured the machine this way as its experience shows concrete supply can be problematic in developing countries, so paving in two passes can be more practical than in one pass. Standard equipment for the SF-1700 includes a Cummins QSB4.5 diesel rated at 127kW, spread auger and tamper bar, and 12 Wyco vibrators although more can be fitted if required. Vertical adjustment of the vibrators is controlled by the operator using the hydraulic power lift system, while the baffle plates between the vibrators can be removed if required.

The fully proportional sensing system allows automatic steering from grade references and the SF-1700 is equipped with connections for both right and left hand referencing. The 1.17m profile pan has a power crown for straight crown configurations and adjusts automatically for grade variations of up to 609mm during paving. Kerb mold inserts can be installed on either side of the profile pan, while 810mm high sideforms allow the machine to carry sufficient concrete to cope with deep pours. The firm says that the profile pan, tracks and sideforms adjust automatically from running with both tracks on the ground to having one or both tracks running on the adjacent slab.

3956 Terex Roadbuilding says that the latest version of its Bid-Well 4800 bridge paver and Bid-Well 2418 work bridge deliver high performance and accuracy in a range of applications. Manufactured at company’s new 7,432m2 facility recently completed in Canton, South Dakota, the 4800 paver offers standard paving widths exceeding 51.8m and features several upgrades that make it well suited for use by bridge contractors. A new style fogging system features all poly tubing to increase up-time as well as individually controlled spray nozzles that direct the fog to where this is needed. A new skewable power crown adjuster enables operators to automatically make changes to the crown when paving bridge decks at the skew angle.

The 4800 is said to be versatile and is available with several options that can tailor the paver to meet an array of specific jobsite conditions. These options include a swing leg design for zero-clearance paving; and a pivot leg design for paving cross slopes of 6-8%. The optional 381mm Rota-Vibe system on the show machine’s paving carriage allows for longer machine advancements than the standard unit, which is said to be useful for paving streets and highways. Another feature available is the dual drag pan arrangement, which is said to help contractors achieve a better concrete seal and enable the pans to drag directly to the side of the slab.

Meanwhile the Bid-Well 2418 work bridge offers a 610mm wide walkway over its 457mm deep truss frame, allowing crew members to cross freshly laid concrete surfaces to perform tasks behind the paver. The 2418 provides standard operating width of up to 32m and its telescoping end segments offer up to 3m of leg travel to each side, so the work bridge can adapt to varying deck widths. Multiple leg and wheel configurations are offered such as the standard bolt-together, fixed-height leg and an optional screw-jack design that enables work bridge height to be raised for passing over obstructions.

The 364 Wirtgen Group is now active in the US market, having introduced its SP15 and SP25 models. One of the firm’s latest developments has been a novel 3D steering system, called the Autopilot package, which can be used with the firm’s SP15 and SP25 slipform pavers for poured-in-place concrete profiles, such as kerbs or safety barriers, in offset application. This straightforward system that is said to be easy to install and use, as well as being cost-competitive compared with existing technology.

The Autopilot package uses a similar layout to Wirtgen’s other machine control systems and uses GPS technology to provide guidance for the machine’s steering functions. An augmentation centre for the vertical control provides millimetre accuracy for height and it uses special software running on proven hardware. It can cope with straight profiles, complex curved profile paths, or closed profile configurations and can produce radii of 600mm. This dispenses with the need for surveying and removes the need for setting out stringlines (and removing them after use) as well as helping reduce both time and costs for the contractor. There is no need to use a digital terrain model as programming of the profile path or profile configuration can be carried out on site-based data generated in the field and the system automatically negotiates obstacles on site, such as manhole covers.

This system is said to be far easier to program and difficult shapes such as islands for parking lots can be stored on the computer and used for subsequent jobs, with only minor adjustments needed to change paving radii and other dimensions. The system comprises a computer integrated in the machine as well as a control panel, with two GPS receivers on masts communicating with a GPS reference station located on site.