Kariba Dam Pool Rehabilitation Project
Project Summary
The Kariba Dam Pool Rehabilitation Project addressed critical structural risks at one of the world’s largest dams, ensuring the safety of millions and the continued supply of hydroelectric power to Zambia and Zimbabwe.
The project involved innovative engineering, including the construction of a world-first cofferdam under an existing dam, extensive underwater concrete works, and advanced admixture solutions from Chryso to achieve watertightness, durability, and resilience. Despite formidable technical, environmental, and safety challenges, the project was completed with minimal impact on local communities and the environment, setting new benchmarks for dam rehabilitation in Africa.
Chryso Expertise
Chryso®Omega 162 reduces the need to add extra water, and so increases the durability of concrete. This admixture also improves cohesion and lowers viscosity in the concrete mix, leading to improved homogeneity and superior off-shutter finishes.
Facilitating the release of formwork from the concrete piers is Chryso®Dem S, a versatile mould-release oil for timber or steel.
Project Solutions Used
Waterproofing / Watertight Concrete:
- Chryso®Omega 162 – Superplasticizer for durability, cohesion, and finish quality
- Chryso® Fuge B – Pore-blocking permeability reducer
- Chryso® Aquabeton ZA – Underwater concrete admixture to minimize washout and segregation
- Chryso® Quad – Improves cohesion and viscosity
- Chryso® Jet 30 – Shotcrete adhesion for dam wall stabilization
- Chryso® NS Grout Additive – Non-shrink grout for anchoring and fault stitching
- Chryso® DEM S – Mould-release oil for formwork
- Chryso® Fluid Optima 206 – Pumpability and durability in high-strength mixes
Project Challenges
Erosion of bedrock at dam base threatening structural integrity.
Construction of a watertight cofferdam under an existing dam (world first).
Underwater concrete placement in strong currents and variable temperatures.
Micro-blasting and excavation near fault lines and dam foundation.
Managing health & safety in high-risk conditions (including COVID-19 and wildlife).
Ensuring minimal environmental and community impact.
Achieving stringent quality and durability standards for concrete under extreme conditions.
Chryso Southern Africa honoured at the 2025 Fulton Awards:
WINNER
Infrastructure > R100 million value
Chryso Southern Africa honoured at the 2025 Construction World Best Projects Awards:
WINNER
Civil Engineering Contractors category
WINNER
AfriSam Innovation Awards for Sustainable Construction
Project participants
Client: Zambezi River Authority
Contractor:Razel-Bec
Chryso Solutions Supplier: Mart Solutions
Consulting Engineer: Gruner-Stucky
Admixture Manufacturer: Chryso Southern Africa
Other references
VAL DE VIEW BERG RIVER BRIDGE
A range of CHRYSO products contributed to the success of a bridge project near the historic city of Paarl in South Africa, involving the largest precast beams cast to date in the Western Cape.
VLAKFONTEIN RESERVOIR
In November 2020 started the construction in South Africa of the Vlakfontein reservoir in Benoni, Gauteng. The circular post-tensioned reservoir, which will store 213.4 million litres of potable water, is the country’s largest cylindrical post-tensioned concrete reservoir, one of the biggest in the world. Due to its enormous size, it may also be classified as a dam.