Con-Solve Civils and a.b.e. Construction Chemicals safeguard vital water infrastructure

Durban Heights Reservoir No. 3.

Durban Heights Reservoir No. 3, a monumental 340 megalitre structure constructed in 1971, stands as a critical hub for potable water storage in South Africa. This reservoir, nestled in the Reservoir Hills area within the eThekwini Metro, plays a pivotal role in supplying water to over half a million residents in the northern parts of Durban, including the INK region and Phoenix. Recognising its significance, a comprehensive remedial project was undertaken to preserve the essential water supply infrastructure.

In November 2021, Con-Solve Civils, a renowned multi-disciplinary construction company specialising in concrete structure protection, was entrusted with the waterproofing contract to rehabilitate the reservoir’s distinctive domed roof structure spanning approximately 24 000m2. This marked the initial phase of the extensive project, preceding structural repairs within the reservoir.

Waterproofing excellence: The waterproofing project embraced a range of specialised a.b.e. products, including the removal of the original torched membrane system. The application involved the use of a.b.e. Bituprime, a solvent-based bitumen primer, and abedex Unigum 4 mm, a bitumen-polymer reinforced elastomeric waterproofing membrane suitable for hotter climates. a.b.e. Silvakote, a reflective bitumen-aluminium paint offering UV protection, and abedex HM, a high movement reinforcing torch-applied membrane, were also integral to the process.

The meticulous methodology employed by Con-Solve Civils ensured the seamless application of these waterproofing products. The innovative single-layer dual-reinforced Unigum 4 mm membrane was heat-fused, creating a robust seal with mortar fillets and finishing touches with Silvakote. Counter flashings with super laykold, joint installations with malthoid 3 ply and abedex HM and the waterproofing of the concrete ring beam with abeproof PU Eco were all executed with precision to complete the domed roof waterproofing.

Environmental considerations and innovation: Noteworthy in this project was the environmentally friendly approach. a.b.e.’s abeproof PU ECO, a flexible water-based polyurethane membrane, was used for concrete rehabilitation with reduced environmental impact. Certified as environmentally friendly, this product significantly lowered the project’s carbon footprint while offering effective waterproofing.

Internal joint repairs: Following the successful completion of the roof waterproofing, the Umgeni Water Technical Team identified the need for internal joint repairs. Con-Solve Civils awarded the task and collaborated with a.b.e. technical team to install the Durajoint Flexband high-performance waterproofing bandage system. This unique system also including duraband and epidermix 318, replaced the old vulcanized system, to ensure the secure sealing of expansion, construction, and contraction joints in the concrete.

Within the central floor area, it was discovered that negative water pressure was causing water ingress through the joints and to combat this, the use of a.b.e.-distributed The Works sealant and adhesive was instrumental. This is a unique product that can be applied in submerged conditions, alleviating the problem of water ingress yet allowing for the bandage installation.  This facilitated uninterrupted joint remedial work throughout the reservoir internally, saving valuable time and resources.

The drainage outlet chamber, as well as associated concrete wall structures also required attention and the application of a.b.e. duraflex, a flexible cementitious system was brush-applied without the use of a membrane – which represented a unique use of the product.

External rehabilitation: The external work addressed the external upstand walls of the entire reservoir structure, and dish drainage channels, including the butts to the surrounding reservoir concrete pavement.  Innovative products such as a.b.e. duraband, epidermix 318 epoxy adhesive, and duraflex were applied, providing UV stability and effective protection. Silocoat, a two-component polymer-modified cementitious coating, coated the entire external wall structure, ensuring durability and protection.  Wall joints were rehabilitated using Duraband.  Silocoat is approved for use in contact with potable water; withstands high positive and negative hydrostatic pressures; ingress of CO2 is equivalent to 5 – 6 meters of concrete applied at 3 mm thick; and is an effective barrier to sulphates and chlorides and low pH.

Successful completion and ongoing collaboration: Despite the challenges, Con-Solve Civils successfully completed the project within the stipulated project requirements. a.b.e., with over 90 years of quality products, and technical expertise, played a crucial role in the collaborative effort with Con-Solve Civils and Umgeni Water, showcasing the importance of cooperation in the successful rehabilitation of this iconic 340 megaliter structure.

The Durban Heights Reservoir No. 3 remedial project solutions and installations implemented not only stand as a testament to the synergy between innovation, social responsibility, and environmental consciousness, but more importantly, in ensuring the resilience of critical infrastructure for the well-being of communities.

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