Concrete construction: Embracing new ideas
By Helen Wright10 May 2013
From the installation of efficient new engines in concrete mixer trucks, pumps and pavers, to the creation of new processes for producing concrete and cement in the first place – the pace of change in this sector is fast.
So far this year has been no exception, with a string of new machines showcased at April’s Bauma exhibition in Munich, Germany, all sharing a high efficiency focus, from hybrid truck mixers to innovative new formwork moulds.
Elsewhere, manufacturers have been supporting concreting activities on construction projects around the world, coming up with tailor-made solutions to unique sets of problems.
And the sector’s major producers are also embracing new ideas. Heidelberg Cement, for instance, maintains that the industry is the source of about 5% of global CO2 emissions attributable to human activity.
With this in mind, the company has developed a new cement binder called Ternacem, which it says can be produced with -30% fewer CO2 emissions. The company is planning a large-scale trail of the material later this year in Germany.
Heidelberg’s new approach is to combine calcium sulfoaluminate (CSA), a material used in screeds and tile glues, with belite (dicalcium silicate), which is the mineral in traditional Portland cement that provides its late strength. Energy costs for producing the material are said to be -15% lower due to reduced fuel consumption, thanks to a lower burning temperature, and a less energy-hungry grinding process.
Meanwhile, a Boston Consulting Group study sponsored by the European cement association, Cembureau emphasised that growth in Europe’s cement and concrete industries had to be harnessed in a sustainable manner, by taking into consideration the environmental and social impacts.
The report said Europe’s cement and concrete industries contribute a total production value of € 74 billion (US$ 96 billion) to the economy. Ignacio Madridejos, Cembureau’s president said innovative products and processes would help position cement and concrete as the products of choice for construction. “As locally-sourced and produced products, they will help build Europe’s infrastructure that protects people, property and environment.”
This search for integrated solutions is also reflected in the latest equipment developments. Mixamate for instance has developed a new machine that combines concrete mixing and pumping in one vehicle.
Currently undergoing trials in London, UK, the on-highway vehicle is 12 m long, and is said to be able to navigate site and residential road access. It is capable of administering up to 12 m3 of concrete per delivery and has a 50 m delivery hose.
The unit uses Mixamate’s Conqueror Mixing technology system – each ingredient that goes into the mix is weighed and monitored by the machine’s on-board computer, providing a print-out documenting exact quantities.
Mixamate managing director Chris Smith said, “We have integrated robust concrete pumping machinery directly with a mix-on-site vehicle to create a brand new type of machine in the batched on site industry.
“The Concrete Pumping Truck provides an all-in-one service for the on-site delivery, mixing and pumping of concrete from a single vehicle, which eliminates the need for a separate pump to be delivered, reducing costs, hassle, and CO2 emissions.”
Meanwhile, Simem has been concentrating on the mobility of its concrete batching plants, and showcased its Eagle and MMX range of portable plants at this year’s Bauma exhibition. Modular elements with pre-installed pneumatic-electric systems are the key factors to allow the Eagle plants to be moved very quickly from one project to the other, while the MMX plants are described as ‘supermobile’ and targeted at fast moving projects such as railways and highways.
Simem has also formed a strategic partnership with concrete pump manufacturer Putzmeister in a move that the companies hope will create a “one stop shop” for any kind of concrete project, from ready-mix to precast to projects worldwide.
The deal comes after Putzmeister acquired German truck mixer manufacturer Intermix from its owner Hans-Georg Stetter last year. Putzmeister is itself owned by Chinese construction equipment manufacturer Sany.
Simem said the strategic partnership with Putzmeister would allow it to integrate its own batching and mixing programme with Putzmeister’s concrete pumps, as well as the truck-mixers from Intermix.
Co-operation is also crucial when it comes to getting large infrastructure projects completed on time, and manufacturers are increasingly demonstrating their drive to work not only with contractors but with other manufacturers from the sector in order to get the job done.
Putzmeister teamed up with falsework and formwork manufacturer Peri, for instance, to support construction of the Zhuhai Tunnel, part of the Hong Kong-Zhuhai-Macau crossing in China.
A six-lane road bridge, combined with the Zhuhai Tunnel – said to be the world’s longest underwater road tunnel at 6 km – is being built to cross the 35 km stretch of water in the Pearl River esturary in order to connect Hong Kong to Macau via Zhuhai.
The US$ 11 billion Zhuhai Tunnel is being built at a depth of 40 m and must be capable of withstanding earthquakes. Once finished in 2016, it will consist of 33 sections, each of which will be
180 m long. Each tunnel section consists of eight individual segments, 22.5 m long, 40.5 m wide and 11.3 m high.
A window of just 24 hours was available for concreting each segment – a job that required 3600 m3 of concrete. The fully automatic formwork is then stripped, the segment moved forward by 22.5 m and the next segment concreted against it.
Once eight segments are ready, they are joined together and sealed. The basin is flooded, and the eight segments are then towed by ship as a complete, 180 m-long tunnel section to the installation position, sunk in a controlled operation and secured in position. Putzmeister said 890,000 m3 of concrete would be needed for the 264 segments.
Meanwhile, RMD Kwikform Oman supplied over 13,000 m2 of shoring and slab support equipment to the construction of the Majlis Oman Project – a 101,000 m2 complex being built by contractor Carillion Alawi in Oman to house the country’s parliament meetings.
The light-weight aluminium Alshor Plus shoring system was selected for the job. RMD Kwikform design engineer Ino Mutuc said the product was very versatile.
“It can be used in a number of ways, including static towers and moveable table forms to support loads of up to 120 kN per leg, which provided us the flexibility we required to provide an efficient and safe solution for the construction of the Majlis Oman.
“Throughout the project we have had to support reinforced concrete slabs of heights that vary from 3.90 m to 13.20 m. By using Alshor Plus tables to form these slabs we were able to use one system for all of the pours. We have been able to pour and cure a section of slab, then move onto the next section efficiently and safely due to the quick release mechanism incorporated into the Alshor Plus jack,” Mr Mutic explained.
Carillion project manager Paul Buttery described RMD Kwikform’s commitment to the project as “outstanding”.
“They have not only supplied an extremely efficient shoring system, but also designated an engineer to be onsite throughout the build to provide frontline support and make sure we get the most out of the supplied solution,” Mr Buttery said.
The paving sector is also changing rapidly, and high efficiency is the name of the game here. GOMACO, for example, has introduced the GT-3200 zero-clearance sidewalk paver, designed specifically for rehabilitation projects.
The three-track machine features an adjustable aggregate base mould on the front and a sidewalk paving mould on the rear. It is also fitted with a 508 mm wide, 4.3 m long folding conveyor that can rotate 180° to allow for easy loading of concrete into the hopper from either side of the machine.
The GT-3200 can be transported without removing either mould by folding the conveyor and driving the machine onto a trailer for transport. It is also equipped with GOMACO’s G+ system, which is said to boost paving accuracy through electronic monitoring of steering and grade.
Phoenix Curb Machines, meanwhile, claims its 7500 slipform curb and cutter machine saved a contractor in the US time and money during a retrofitting contract, compared to using a larger slipformer.
The project supervisor from contractor Green River Group, which was hired to retrofit a parking lot at West Virginia University Campus in Morgantown, needed one day of training prior to the pour. A 20 in (508 mm) curb needed to be installed, 14 in (356 mm) below the existing surface with 6 in (152 mm) exposed.
Phoenix claims the contractor paid -33% less for a mid-size, more nimble machine that did most of what the bigger machines can do, while set-up time for the 7500 is said to be 30 minutes, compared to up to several hours for some larger machines. This includes unloading the machine and putting it on the stringline.
The 750 also demonstrated its versatility during the job by pouring a curb while turning, travelling uphill and levelling the curb against different pitches on the roadway thanks to its Topcon System 5 Sonic machine control technology.
Steve Calvery, owner of Green River, said he had initially been sceptical about the 7500 when he first heard about it. “Our scepticism has changed to enthusiasm,” he said. “It has all the elements combined we need. The ease of mobility, operation, set-up, clean-up and the quality of the curb was even better than we hoped.
“It’s easy to operate because you don’t have feeder belts and there are fewer moving parts that you have to maintain and operate. The Phoenix Curb Machines are smaller and more compact. It’s easier to move from site to site than your typical curbing machine.”
It is clear that manufacturers are increasingly ready to work very closely with contractors to help them select and operate the right machine for their concreting task. This process of feedback is also helping manufacturers to tailor new machines to specific challenges, and improve the efficiency of the whole sector.