The CLS structural formers are made from 100% recycled plastic, making it possible to use up to 35% less concrete.
Cobiax The CLS structural formers are made from 100% recycled plastic, making it possible to use up to 35% less concrete.

Heinze Cobiax Deutschland GmbH, provider of voided-slab systems for sustainable slab construction, presented their new product Cobiax CLS - Concrete Lightweight Structures - at the Munich trade fair, BAU 2019. During a keynote address, Managing Directors Dr. Karsten Pfeffer and Volkmar Wanninger presented the patented structural formers for reinforced concrete slabs and outlined the new features.

The CLS elements differ from the Cobiax Eco-Line and Cobiax Slim-Line models, in having a square footprint, 60 x 60 cm, with a quarter void at each corner. The innovative structural former half parts are available in seven different sizes from 50 mm to 290 mm tall, meaning a total of 19 different combinations of structural formers enable various slab thicknesses, from 20 cm to over 80 cm. The design of this latest development has huge benefits for logistics and assembly, and the environment.

"We want to reduce CO2 emissions from reinforced concrete construction by a total of 1 million tonnes over the next 5 years using our CLS structural formers, and bring about a rethink in sustainable construction through our products", explained Dr. Karsten Pfeffer.

More than 14 million square meters of Cobiax voided flat slabs have already been produced, corresponding to 2 million tonnes of concrete saved and a CO2 reduction of 180,000 tonnes, this objective seems quite realistic.

"Like all our products, CLS structural formers are made from 100% recycled plastic, and make it possible to use up to 35% less concrete compared with solid slabs. We can increase CO2 reductions resulting from this new square design for the CLS structural formers even further, as these save space during transport," explained Volkmar Wanninger. "The units are stacked up and only put together once at the construction site."

The eco-friendly and economical technology replaces concrete in slabs with voids, wherever the structural design allows. The areas required for load-bearing are integral part of the individual structural formers. These can be laid in a row quickly and easily without gaps, so that no time-consuming lining-up is needed. They can be used for covering 60 to 80% of the total slab area. A Cobiax slab with CLS structural formers can be designed by any structural engineer, following usual standards along with expert and test reports. The Cobiax website features a tool to help select the appropriate product for the desired slab depth.

Square Modules Make Logistics and Assembly Easier

"With every construction project, speed and easy individual component assembly on site are essential," explains Wanninger. "That's why we've developed our tried and tested system further, to reduce overall weight, make assembly easier, and enable even more efficient transport."

The square plastic elements are available in seven sizes, 50 mm - 290 mm tall, 60 x 60 cm square. The CLS structural formers have a quarter void at each corner. The individual half parts can be put together in modular form, in this way enabling up to 19 different combinations which allow slab thicknesses from 20 cm up to more than 80 cm, extending the existing range by five more sizes.

"When assembled, the CLS elements, which can easily be laid out in a row without gaps, automatically form a stable structural design using voids. At the same time, they guarantee reliable load bearing ability without using additional steel", explains Wanninger. "In addition, Cobiax CLS can be stacked up to save space, so that the room available in a truck can be used efficiently and a larger quantity can be transported. This not only reduces logistical costs, but also fuel consumption."

Sustainable Building Materials Reduce CO2 Emissions

With Cobiax, solid concrete slabs are also needed in some areas due to structual design, to ensure the required load bearing ability. However, up to 80% of the total area can be created with enclosed voids using Cobiax products. The amount of concrete needed can therefore be reduced by up to 35% along with some 20% saving in reinforcement steel. As a result, environmentally-harmful CO2 emissions have been reduced demonstrably, by up to 20%. In doing this, Cobiax is optimizing the ecological balance sheet for buildings.

"The sustainability of our products is evidenced through a type III Environmental Product Declaration (EPD)", says Pfeffer. "Additionally the resource and energy-efficient use of materials has been rated positively as part of sustainability certification such as DGNB, LEED and BREEAM, thereby increasing property value."