Unimix, one of Dubai’s leading readymix concrete producers – with a contract to provide a range of concrete grades for the Jumeirah Beach Residence (JBR) project – recently had to transfer its Lintec batching plant when the land was needed for other purposes.

Although only recently introduced into the UAE, through its Middle East distributor Technobuild Construction Machinery, Lintec’s containerised concept – offering speed of erection and dismantling, ease of installation and the ability to produce quality end products – proved ideal for Unimix, says a spokesman for Lintec.
With the original location alongside the Jumeirah Sheraton hotel being taken up for construction purposes, Unimix was required to move to an alternative site located within the JBR compound several hundred metres away.
“Timing was critical as contractors had completed much of the foundations for the project’s 20 towers and a constant supply of concrete was needed for above-ground pours,” says the spokesman.
“With Unimix able to temporarily meet demand from a second batching plant, it needed the Lintec system to be ‘up and running’ as quickly as possible. Whilst the second plant was close by, it meant using the busy Sheikh Zayed Highway, which together with Dubai’s heavy traffic congestion and restrictive use on its main highways for trucks, posed transportation difficulties,” he adds.

Containerised concept
Lintec’s individual plant units, which are installed within 100 per cent ISO sea containers to provide a compact transportable system, offer many advantages. Even though the plant was not moved a great distance, it did not require the need for low loaders since the containers are neither over-width nor over-weight.
Once moved, its large base meant that the container could sit on a normal compacted site surface without the need for concrete foundations. The re-assembled plant was ready for ‘fine tuning’ once the pre-installed pipes and cables had been connected and production was started within a week of moving, he points out.

Unimix
Operating round the clock, the Unimix depot with two batching plants producing almost 200 cu m/hr of a variety of products for the foundations contract, supplied more than 500,000 cu m in just 18 months. At its new ‘base’, the plant is running 24 hours to provide an anticipated 750,000 cu m for its 20 towers concrete placement contract – served by Unimix’s fleet of up to thirty 9 to 12 cu m capacity mixer trucks.
At the input of the system, two 40 ft containers – each split into three compartments – provide aggregate storage bins, offering a storage area of 200 cu m.
Two moisture centres within the bins ensure that the water content within the aggregate is automatically controlled. Unimix generally works with a mix of five different-sized aggregates up to a maximum size of 20 mm dia.
Unique to the Lintec system is a pre-weighing system below the storage components, allowing Unimix to weigh the content of each respective compartment at any time - compared with a conventional weigh belt system which only allows measurement to be made in one compartment at a time resulting in frequent stop-start operation.
Lintec’s continuous belt operation system eliminates stop-start to provide very fast loading cycles. The belt feeds onto an 80 ft incline conveyor housed within two halves of a 40 ft container. On installation, the container is hinged open to form two units, which are bolted together at an incline angle of 29 degrees.
The Jumeirah installation features a twin tower configuration with each tower comprising a mixer unit and a weighing unit, now installed within 20 ft ISO containers.
The height of the mixing compartments is determined so as to allow easy drive-in access and loading of the cement trucks beneath the mixer. Two 20 ft containers, once again split in half and housing instrumentation, support the raised twin towers.
Ten 80 cu m silos ensure an 800 cu m storage capacity with five serving each twin tower. Since Unimix prefers to blend the mix, each twin tower can be served with, for example, cement, fly ash and GGBS (ground granulated blast furnace slag) slag.
Each silo comprises a 20 ft container at the base and a 40 ft unit at the top to provide a 60 ft height. The installation also features a 25 cu m microsilica silo located on top of the weighing container providing automatic injection as required. All the silos are equipped with piping to allow easy dust-free filling by a pneumatic conveying system.
A distribution belt at the top of the incline conveyor conveys material to each of the towers as required, into the weighing containers. At the same time, the specified cement-mix, with any microsilica is also weighed.
Once the correct weight has been achieved, the materials are fed to the mixing container housing a patented Lintec twin shaft mixer. With two 55 hp motors, the belt-driven mixer also features fluid coupling to protect the motors.
In order to ensure operation throughout the high summer daytime temperatures experienced in the Gulf – often in excess of 40 deg C, Unimix has opted to use an ice flake system to cool the final mixed product. Supplied by KTI Plersch Kältetecnik, the ice weigher is installed at the foot of the incline conveyor for automatic mixing with the aggregate.
Once the project is completed, Unimix will be able to easily dismantle the complete installation and move it to its next location in just a matter of days.