Steve Skinner reports on technical advances in concrete construction

Attention to detail is the hallmark of the latest equipment designed to increase accuracy, performance and longevity in concrete construction. Steve Skinner reports on some of the technical advances being made.

From hand held equipment for small contractors through to heavyweight concrete pumps, the continuing evolution of equipment is enabling faster and more accurate work flows for those dealing in the concrete sector.

Typical of this is Wacker Neuson which launched its new DF16 rebar tie in May, designed to increase the speed, efficiency and ease of tying rebar. Markus Martin, product manager of concrete technology at Wacker Neuson said, "An experienced steel fixer can tie up to 40 knots per hour, while the DF16 can easily manage 1000 per hour. The quality of the knots is first class, and remains consistently high despite the increased productivity."

The DF16, which adopts a mechanical system for durability, is placed on the reinforcing steel by the operator who needs just one hand to press it down. The ‘press' releases a tie wire from a cartridge containing 77 ties, which then wraps around the rebar with loops at each end automatically interlocking. As the DF16 is withdrawn, the wires are twisted together.

"This device eliminates the steps that place a strain on the body and make tying with pliers so difficult," said Mr Martin. "This represents a significant reduction in physical stress for workers as well as eliminating the time-consuming process of removing excess wire."

Alongside the DF16, Wacker Neuson has also developed an eight strong range of electro-hydraulic steel cutters for rebar. "Compared to other cutting systems such as angle grinders and flame cutters, our new reinforcing steel cutters are more efficient, quieter and safer," said Mr Martin. "The electro-hydraulic mechanism generates minimal noise and the danger of injury or damage through flying sparks is eliminated."

With three economy versions under the RCE nomenclature and five RCP premium models, the RCP-20, RCP-25 and RCP-32 top-of-the-range steel cutters, are capable of cutting steel bars with a diameter of 20 mm or more.

Stone Construction meanwhile, recently added a 26 strong series of diamond saw blades to its masonry and concrete range. The laser-welded blades are better balanced and flatter than earlier versions and deliver faster and straighter cuts.

Ranging in sizes from 305 mm to 508 mm, the new diamond blades can cut block, cured concrete, green concrete and asphalt over concrete. The range fits all 25 mm arbour saws and can be used wet or dry.

Also new from Stone Construction is a pair of hand-held, lightweight, vibrating power screeds. The range topping Stone Screed Bull VSB80 is a heavy duty professional contractors model, which can handle boards up to 4,9 m, yet weighs only 14,5 kg. The rental-ready model, the Stone Screed Bull VSB70, weighs 11,3 kg and can handle boards of 3,7 m. Both screeds deliver optimum performance in 51 mm to 229 mm slumps.

"The triangular geometry of these extruded aluminium screed boards generates dual vibration," said Ed Christopher, vice president of international sales. "This horizontal and vertical vibration enables the operator to both compact and cut concrete."

In the mix

As concrete formulations become more sophisticated, mixing technology needs to develop too according to Ammann.

Andreas Koller, head of the concrete department at Ammann told CE, "We're now offering standardised integration of components in our mixing facilities so that customers can benefit from a high proportion of in-house production.

"A key example of this is our semi-mobile JustWhite facility equipped with an Amix twin-shaft paddle mixer capable of processing 1,5 m3 batches, and featuring a capacity of 70 m3 per hour thanks to the Ammann AS1 control system."

With this facility, Ammann has fitted a mixer camera so that operators can keep an eye on the mixing process. "The camera is installed in a spherical housing, which swings out of the mixing chamber during filling or cleaning in order to protect the lens from dirt and damage," said Mr Koller. "A video monitor in the control room enables the operator to keep a previously impossible visual track of the mixing and emptying process."

The feeder lining, mixing arms and blades of the Amix mixer have all been given a wear resistant coating. "Where the material to be mixed is especially abrasive, Amix can be fitted with amdurit wear plates (a composite much tougher than Hardox steel), which increase the service intervals by up to five times," Mr Koller told CE.

In the ready-mixed precast sector, Imer Group has completely redesigned the distribution system with its Ory Fly overhead system. Featuring improved versatility, the Ory Fly works equally well on straight or curved routes and has been designed with power optimisation in mind. With reduced noise and an ergonomic design for ease of maintenance, the Ory Fly is available with rotary discharge for liquid concrete and with bi-valve discharge for semi-dry and dry concrete.

Like Ammann, Imer has recognised the advantage for operators of autonomous and modular batching equipment, and this is reflected in the Group's BTK 1008 concrete mixing facility.

"Thanks to its mono-block structure, the BTK 1008 can be adapted to suit various construction needs, while producing a uniformly high quality product," said Paolo Salvadori, president of the concrete machinery division. "The operator can set the required level of fluidity, which is then kept constant through the use of the Imer auto-compensation water mechanism."

Pumping

Following last year's merger between Zoomlion and Cifa, two Zoomlion 37X-4Z truck-mounted concrete pumps with 37 m booms were sold to Spanos, a Cifa dealer, at April's Intermat exhibition. "This was a significant moment for us as it could be regarded as the physical launch of Zoomlion concrete pumps into Europe," said Jimmy Pan, head of concrete products at Zoomlion.

"Beyond this, the market is in deep depression," Mr Pan told CE. "That said, we see the future of the European concrete industry as promising, although we only see the market picking-up in 2010."

Zoomlion is currently making market adaptive modifications, based on which the company will develop new models specifically for Europe. "Alongside product research and development, we see the next year as an opportunity for us to build a sophisticated market channel and develop our service and spare parts support system in Europe," said Mr Pan.

Intermat was significant for Putzmeister as it launched its BQF 06 Roline model for the small-scale construction market. The machine places concrete using pipes and flexible hoses, rather than a boom. This means the truck chassis can be smaller which enables access to confined spaces.

The project uses the R60 rotary pump from the Pumi range, capable of delivering up to 58 m3 per hour at 25 bar pressure. The rotary pump features low wear and quiet pumping with an infinitely variable forwards and reverse delivery rate which leaves little residual concrete in the hopper.

Mounted on a Mitsubishi Canter 7C18 7,5 tonne chassis, the BQF 06 Roline can deliver a wide range of materials including difficult substances such as steel fibre concrete, free flowing screed, foam concrete, self compacting concrete and lightweight concrete up to a particle size of 32 mm.

"We've bucked the trend and gone small," said Olivier Saint-Paul, managing director of Putzmeister France. "The renovation sector continues to be buoyant and this machine's been developed for this and for the smaller construction professional."

"We see a good market for this machine in most of Europe, but especially in the UK, France and Germany where there are many projects being conducted in confined areas," said Mr Saint-Paul.

Evolution

Improved productivity in the concrete sector goes hand-in-hand with ever more aggressive contractual deadlines. While scientists might research chemical enhancements and modifications to speed the curing process of cement, manufacturers are honing their equipment to make it more efficient and durable, while maintaining flexibility.

At the same time, alternative aggregates and eco-minerals may help the global recycling initiative, which is yet another small step in the drive to reduce man made CO2 emissions.