Aggregate producer Afri-
 Sam has been awarded 
 the contract to supply aggregate and 200 000 t of 
cement to the Gautrain Rapid Rail Link project south section by construction company Bom-bela Civils Joint Venture (JV).

Bombela Civils JV concrete scheduling manager Eugene Francis says: “Durability was a major contractual requirement and AfriSam’s use of cement, slagment, fly ash and additive mixtures in our product ensured adherence to this requirement.”

Afrisam contract manager for multiproducts: key accounts Graham Hannah adds: “The consistency of our all-purpose
cement (APC) is extremely 
accurate and means that quality 
is assured. The customer does not have to invest capital in doing 
on-site blending.”

In addition to the APC, Afri-Sam will also supply smaller quantities of its high-strength cement (HSC) and rapid hard cement (RHC), with product being primarily supplied from its Roodepoort facility, with its Brakpan facility as a backup source of supply to ensure continuity of supply from AfriSam.The cement will be delivered in bulk to three batching plants as well as bagged cement to various construction points for small works and the sections of the tunnel which are being grouted.

AfriSam will be supplying aggregate to Park station and Rosebank station with a supplementary supply to Marlboro, where the spoils from the tunnelling are being recrushed and used as aggregate wherever possible. “Aggregate from AfriSam is only used at this operation as a supplement when necessary. This differs from Park station, which uses AfriSam aggregates in the readymix, as the logistics of trucking the crushed spoils to this operation would not be cost effective,” Francis explains. The location of AfriSam’s quarries has dictated that aggregate is delivered to Park station from its Eikenhof quarry south of Johannesburg.

The readymix being used for
the tunnelling, cut-and-cover 
operations and the volume required, necessitated that Gautrain has its own batching plant. On average, some 701 m3 a day comes from the Marlboro batch plant. This is the largest operation with two batch plants, while Park station and Rosebank station both produce about 
110 m3 each a day.

“Quality control is also important and we take responsibility for our plant. The standard of the readymix being used for the Gautrain project is benchmarked against international standards and quality control on all batch plants is stringent to ensure that there is no deviation from this design mix,” says Francis.

For the readymix, 9,5-mm-
diameter stone, 19-mm-diameter stone and crusher sand, as well as APC cement, are used. 
The spoils are transported from the various Gautrain sites to the internal crushing site 
situated near Linbro Park where the material is then crushed to specification. It is then transported back to Rosebank and Marlboro. “On average, some 300 t of crushed material 
is used daily,” says Hannah. He adds that the aggregates are supplied from three of AfriSam’s quarries. The 9,5-mm aggregate is from the Jukskei quarry, and the 19-mm aggregate and sand are from its Eikenhof and Oliefantsfontein quarries.

Bombela Civils JV owns the readymix trucks used to transport the readymix from the batch plants to the sites and, when required, additional trucks are hired. 
“A nonstop operation, with four teams working in shifts, 
ensures continuous operation and our laboratory runs 24/7 as every batch is sampled to ensure we adhere to stringent specifications and quality control measures,” Francis comments.

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