On the job ... KTI-Plersch equipment on site.

Plant from a German concrete cooling technology specialist KTI-Plersch Kaltetechnik is playing a key role in the operations of National Readymix Concrete.

"We have supplied four of our ice plants to National Readymix," says a spokesman for the German manufacturer. "The first was sold in 2000 and three more were sold this year."

He continues: "KTI-Plersch Kaltetechnik, a leader in the business of concrete cooling technology, has been selling its plant in the Gulf over the past 15 years and commands more than a 90 per cent share of the market.

"In 2000, the company set up a Middle East office in Dubai, to serve its regional customers better. It has a sales and service office in Jebel Ali Free Zone (Jafz) which is managed by a professional team, and a well-stocked warehouse in Al Quoz.

"The company has sold more than 200 units throughout the GCC, Yemen, Iran and Iraq, Egypt and Africa.

KTI-Plersch Kaltetechnik's plant has helped build major projects throughout the world, according to the spokesman. "We have supplied more than 300 plants for cooling concrete all over the world over the last eight years," he says.

In Germany, KTI's cooling technology is currently being used to build one of the country's biggest dams - the Leibis-Lichte dam in the state of Thuringia.

The massive dam, which is being built to the south of Weimar, not far from the town of Rudolstadt, will be 100 m high, 370 m wide at its crown and 80 m thick at the base.

Part of the Schwarza water supply scheme, the dam is scheduled for completion by 2005 and is intended primarily to collect and store potable water and, secondly, to contribute to flood protection.

The dam complements the Weida-Zeulenroda-Lossau reservoir system and as such forms part of the East Thuringian water supply network. It will help to cover East Thuringia's long-term requirements for high-quality drinking water for its 300,000 residents.

Highlighting the role that KTI-Plersch Kaltetechnik is playing in the project, the spokesman says: "The logistics and technology involved in the construction of the dam make it an extraordinary and challenging project. For instance, the dam is expected to use 620,000 cu m of concrete until the end of 2004.

He continues: "In January 2001, readymix operator Rapid Beton won the order to supply the all the concrete, which is being produced in two large batching plants delivered by IPA of Germany - each equipped with one 4.5 cu m twin-shaft mixer. The main contractor on the project is Bilfinger & Berger.

"In order to supply 2,500 cu m of concrete per day, a total of 1 million tonnes of aggregate will have to be transported in time to the construction site and by the time the dam is complete, more than 1,000 concrete sections would have been built to the highest standards of quality and performance.

"One of the technical highlights of the project is the use of two Krupp cable cranes in concreting operations. All the 620,000 cu m of concrete needed to build the dam is being moved into position by these two cable cranes.

Each crane has capacity of 20 tonnes and a lifting height of 140 m. The cables for the two crane trolleys will have a span of 615 m. The cranes can be moved radially: on one side of the river valley the cables will be mounted on a 14-m high concrete structure, while on the other bank each will be fixed to a mobile car. The two cars will run on a spherically curved track with a maximum 40 per cent incline to slew the cables across the full working area, allowing precision service to all points.

The trolleys each have a holding capacity of 6 cu m and can be used simultaneously to reach a concreting capacity of 200 cu m an hour. Exact time management for concreting operations and operation control will be decisive in completing the project on time, and this is where KTI plays a key role.

"In order to meet international standards the maximum allowed concrete temperature before pouring should be 15 deg C, which means that the concrete should not leave the mixer at a temperature of more than 12 deg C. And during the critical period between May and October this required temperature will be achieved through the use of a sophisticated by KTI-Plersch Kaltechnik concrete cooling system on site.

The cooling system consists of:

  • One containerised water chiller with a capacity of 150 kW, cooling 300 cu m of water per day from 15 deg C down to 5 deg C (installed inside 20-ft container).

  • Two containerised flake ice plants each with a daily capacity of 70 tonnes (each installed inside of a 40-ft container).

  • Two containerised ice storages each with a storage capacity of 40 tonnes (each installed inside of two 40-ft containers).

  • Two ice delivery and weighing systems for delivery of up to 150 tonnes of ice within 13 hours.

    "What makes KTI's plant special is that it comes fully packaged and is easy to set up and use: It is completely pre-assembled, can be placed in less than seven containers and set up on site within a week. The same applies for the dismantling the plant after work is completed."

    "The complete cooling system can easily be resold to other contractors or used on a different construction site anywhere in the world on projects where temperature-controlled mass concrete is required," the spokesman adds.

    20