Gulf Construction Online - Putzmeister and GCS screed way to the top

UAE Focus

The Mixokret M 760 DH in use at the Central Market project.

Putzmeister and GCS screed way to the top

01 November 2011

PUTZMEISTER, a leading construction equipment manufacturer, and German Concrete Works (GCS), the largest floor screed contractor in the Middle East, are together taken screeding technology to new heights in the region.

The two partners are working together to execute major projects across the Middle East, where there is a growing demand for high-quality and sustainable floor finishes.

“Builders today want sustainable, strong and perfectly built-in floor screeds, which of course have to be cost-effective, and the trend towards high-rises in the Middle East has generated new requirements for the screeding process,” says Jochen Knecht, who works at Putzmeister’s Middle East office in Dubai, UAE. “This has attracted specialised screeding contractors of mainly European origin, who are working to adapt their technology and materials to suit Middle East conditions, where tall buildings and large projects have to be built under extreme weather conditions.

He continues: “Furthermore, the requirements for technical equipment are rather immense. For instance, new floor screed conveyors are designed to pump moist material mixes to heights of up to 200 m with a total rubber hose length of 250 m, sometimes in operation on a 24/7 schedule.

“To achieve such record-breaking performances, the latest machine technology and long-time application experience must come together. This is where Putzmeister and GCS have shown perfect teamwork based on 15 years of close collaboration – and large projects in the Middle East provide the perfect setting for their record-breaking accomplishments.”

Floor screeds are cement-based layers between the visible floor finish and the concrete structure of a building. They are generally used to:

• Eliminate tolerances within the slab and provide a solid, flat foundation for tiles, timber, vinyl or other floor finishes (most floor failures including cracks and colour staining are due to faulty preparation);

• Provide additional technical properties such as noise reduction, insulation or waterproofing; and

• Provide a one-step solution and avoid additional works like applying a second self-levelling screed on top of the first.
Screed applicators usually add admixtures to the sand, aggregate, cement and water mix not only to increase its pumpability but mainly to reduce the water content, as less water allows for more control over material shrinkage. In the Middle East, these specialised admixtures are available from various companies such as Diamond, BASF, Mapei, Knopp, Flowcrete and Ardex.

“Compared to other less advanced technologies like ordinary concrete, this cement-based screed allows for quicker drying times which results in increased flexibility within the construction process,” says Knecht, adding that this technology is being successfully implemented in the Middle East.

GCS has completed several prestige projects in the UAE and Qatar with record-breaking pumping heights and distances. Examples include the Maze Tower in Dubai, where screeding was done to the 52nd floor and D1 Tower also in Dubai, where screeding work is currently at the 54th floor.

The German specialist is now taking on a new challenge on a 380-m-high tower at the Central Market in Abu Dhabi. Here, GCS is using a Putzmeister Mixokret 760 screed conveyor, the more powerful in its range, mixing and pumping the material in two steps, first to level 43, and then until the top of the tower.

The M 760 delivers up to 5 cu m of screed per hour and provides remarkable time savings, thanks to a powerful in-built air compressor. Also, its hydraulic mixing apparatus means it can cope with the most demanding conditions, Knecht points out.

The hydraulic drive provides the option to mix in forward and reverse mode. This allows any blockages to be easily removed while considerably simplifying cleaning and maintenance works, Knecht says, adding that the drive is low-wearing and protects the mixing apparatus from overloading.