DAMS & RESERVOIRS
The Vlakfontein reservoir design included a permeable groundwater drainage system comprising three layers of 15 MPa no-fines concrete.
GETTING CONCRETE PERFECT FOR DAMS AND RESERVOIRS
Armand van Vuuren, Commercial Manager Export at CHRYSO Southern Africa.
Ensuring the integrity and constructability of key water infrastructure in the region, CHRYSO® Southern Africa is contributing its admixture solutions to
make the most challenging projects a success.
T his is according to Armand van Vuuren, Commercial Manager: Exports at CHRYSO Southern Africa who says that among these are two path-breaking reservoirs in South Africa’s Gauteng province: Vlakfontein reservoir, which is the largest cylindrical post-tensioned concrete reservoir in the country; and Khutsong reservoir, with Africa’s first round, prestressed raft floor to deal with dolomitic ground conditions. CHRYSO® Southern Africa is also working on the multi-million Euro project to reshape the plunge pool at the base of the Kariba Dam wall. Vlakfontein reservoir With an internal diameter of 154 m – about the length of one and a half football fields – the Vlakfontein reservoir holds over 210 Mℓ of potable water. The outer concrete walls are almost 12 m high, reaching about three storeys. It has a 200 mm thick
floor slab layer that consumed 1 800 m 3 of 35 MPa concrete. This had to be pumped in 13 separate pours of between 250 m 3 and 36 m 3 each. Van Vuuren says the project made use of CHRYSO® Plast Omega 178, a high-performance water reducing plasticiser, in all its concrete mix designs. “This reduced the water content of each mix to 175 ℓ/ m 3 while ensuring workability and strength,” he explains. “This admixture also increases the slump – or flow – without affecting the water content of the mix.” The concrete in the reservoir’s floor slab, wall footing and roof slab was augmented with CHRYSO® Serenis shrinkage inhibitor – to reduce shrinkage of the concrete. CHRYSO® CWA 10 crystalline integral waterproofing agent is also used to reduce the permeability of the concrete in the floor, walls and columns. “When moisture is present, this agent creates a reaction
28 CONSTRUCTION WORLD FEBRUARY 2023
Made with FlippingBook - professional solution for displaying marketing and sales documents online