New flyash storage silo for NPC-Cimpor’s Newcastle depot

Via a joint venture between Construction Solutions and Paramount Construction, a new flyash silo for cement manufacturer NPC-Cimpor’s Newcastle depot has been completed. The company manufactures and distributes cement to hardware retailers and to the readymix, concrete product and construction industries.

The silo is the fourth at the depot and is part of the cement manufacturer’s expansion programme to increase the Newcastle plant’s output and its current bulk storage capacity.

The project started in mid-January 2011 and took under five months to complete. “We are pleased to report that the project was completed on time and without any major challenges,” says Richard Hein, Commercial Manager, Paramount Construction.

Sliding or slip form is an intricate process, a construction method used to build reinforced concrete structures such as silos, towers and columns and refers to the manner in which the concrete is poured. For this project a specialist was appointed to handle the sliding (slip form) construction of the silo.

“A hydraulic climbing shutter is used, which is supported with ready-cast concrete. Jack rods are cast into the concrete and the hydraulic jack attaches to the jack rods and pulls the shutter up, depositing the concrete behind,” Hein explains.

“Timing is crucial, as the concrete may collapse beneath the shutter if the slide progresses too quickly. The temperature and curing rate of the concrete has to be monitored continuously and retarder added, if necessary, to maintain maximum concrete workability,” he added.

To meet the 24-hour demand for concrete during the slides, concrete was batched onsite and transferred to a dumper, which was then tipped into a concrete bucket hoisted by a tower crane. A 1.2 m high slip form shutter was used to support the concrete while it was poured. The concrete had to be poured continuously to prevent a cold joint from forming, ensuring the structure is waterproof.

The silo was constructed in two phases. The first slide to create the 6.7 m high access area beneath the silo was completed over three days in three 24-hour shifts. The width of the shutter was adjusted from 500 mm for the first part of the wall to 350 mm for the rest of the wall, after the third day. The second slide took just under three weeks to complete, meaning the finished silo stands at an impressive 48 m.

Durban-based Kantey & Templer provided the consulting engineering services for the project. The Construction Solutions/Paramount Construction JV was also commissioned to build the pallet storage hardstand at the Newcastle depot and undertake all the concrete work for the onsite packaging plant, which was completed in April 2011.

Read the article online at: https://www.worldcement.com/africa-middle-east/22072011/new_flyash_storage_silo_for_npc-cimpor%E2%80%99s_newcastle_depot/