Construction World February 2023

CHRYSO Southern Africa, together with Mart Solutions, has made a range of technological contributions to the construction of the Kariba Dam plunge pool project.

Pouring of the concrete had to be completed within 24 hours to ensure the homogeneity of the concrete under early stressing. The site’s location demanded close collaboration between the contractor and readymix partner. The final plan made use of three batch plants, 32 mixer truckers, standby plant and personnel, back-up power and water plants. Kariba dam At the world-class Kariba Dam project, where contractors are working to stabilise a plunge pool at the base of the wall, CHRYSO® Southern Africa is making a range of technological contributions, working with Mart Solutions. Before the pool could be emptied, a coffer dam had to be built – requiring a concrete foundation to be placed underwater. Van Vuuren says that contractors minimised the washout and segregation of fresh concrete underwater by adding the innovative admixture CHRYSO® Aquabeton ZA. Another CHRYSO solution being applied in this contract is CHRYSO® Omega 162 superplasticiser, an important

Construction of one of the seven Kariba Dam pier bases to be submerged under water.

component of the concrete mix design for the seven piers of the coffer dam. These large pier structures will range from 250 tonnes to 700 tonnes in weight. CHRYSO® Omega 162 reduces the need to add extra water, thus increasing the durability of the concrete. The admixture also improves cohesion and lowers viscosity in the concrete mix, leading to improved homogeneity and superior off-shutter finishes. CHRYSO® Fuge B, which is a pore-blocking permeability reducer for mass concrete, is also being used for the piers – as they are in contact with water all the time. This product reduces the size of the capillaries to prevent the penetration of water under pressure. CHRYSO® Southern Africa is also providing admixtures for the shotcrete being used to stabilise the walls on the haul roads into the plunge pool as it empties. 

31 CONSTRUCTION WORLD FEBRUARY 2023