AfriSam is supplying specialised readymix concrete for a 43-m-high water tower being constructed by M&D Construction near Johannesburg, to support the provision of essential water infrastructure to approximately 20 000 homes in the Goudrand mega city housing development. Said to be one of Gauteng’s largest and most technically complex water towers, it will have a capacity to store 3.2 megalitres of water and is designed to withstand seismic activity.

The tailored concrete mixes, incorporating high levels of supplementary cementitious materials (SCMs), are said to deliver exceptional strength and thermal control while meeting the project's demanding construction and logistical requirements.

With construction led by M&D Construction and engineering design by SCIP Engineering Group, the project has demanded highly customised concrete solutions from AfriSam. The structure is located in a seismically active zone and required additional reinforcement in the lower section of the shaft to withstand ground acceleration above 0.1 g. This called for increased steel density and a concrete mix that could deliver strength, flowability and controlled heat of hydration.

AfriSam product technical team leader Mduduzi Ndlovu explains that the concrete mix was developed with a high proportion of SCMs to reduce the heat generated during curing. “The base mix comprised 70% ground granulated blast furnace slag and 30% AfriSam High Strength cement, reducing the ordinary Portland cement (OPC) content to just 20%,” says Ndlovu. “Despite the low OPC content, the mix exceeded expectations - achieving the target strength of 51 MPa in only 28 days against the designed 56-day requirement. ”

AfriSam notes that the construction process placed high demands on the readymix in terms of both slump control and delivery precision. With over 210 kg of rebar per cubic metre in some sections, the company developed a high slump pump mix for vertical pours, while limiting slump to 130 mm for slanted sections to avoid concrete sliding off shuttering.

M&D Construction contracts manager Sheldon Temlett highlights the importance of this mix performance. “With such dense steel and complex geometry, AfriSam’s mix gave us the workability we needed without compromising quality. Their team worked closely with us to adjust slump levels and plan deliveries around our 12 m³/hour pour rate.”

Construction of the Main Reef water tower began in September 2024 and is scheduled for completion in April 2026.