CONSTRUCTION WORLD BEST PROJECTS 2023
Category 4: Specialist Contractors or Suppliers
Background:
Durban Heights Reservoir No 3 is a 340 megalitre structure built in 1971 in the area known as Reservoir Hills which lies within the eThekwini Metro. Reservoir 3 feeds eThekwini Metro’s reservoirs that supply consumers in the northern parts of Durban, specifically the INK region (Inanda, Ntumzuma and KwaMashu) and Phoenix. Its capacity is 340 megalitres, making it one of the largest potable water storage facilities in South Africa. The large number of households, businesses and industry that receive water from it illustrates the importance of this infrastructure.
In November 2021, Con-Solve Civils was awarded the waterproofing contract to rehabilitate the reservoir’s highly unusual domed roof structure of approximately 24 000 m2. Con-Solve Civils is a respected multi-disciplinary construction company, specialising in the protection and rehabilitation of concrete structures nationwide.
Prior to the design, supply and installation of waterproofing awarded to Con-Solve Civils for the roof structure, structural repairs were carried out within the reservoir.
Heat-fused membrane waterproofing:
The waterproofing project, for which a wide variety of specialised a.b.e.® Construction Chemicals products was used, including removal of the original torched membrane system. This was replaced with a new waterproofing specification based largely on abedex® Unigum 4 mm bitumen-polymer reinforced plastomeric waterproofing membrane supplied to Con-Solve Civils by a.b.e.® KZN operations.
The specification for waterproofing products supplied by a.b.e.® was the following:
- bituprime – a solvent-based bitumen primer for use on porous and non-porous surfaces for the consolidation and preparation of the surface. It is used as a primer for bitumen-based topcoats, and torch-on membranes.
- abedex® Unigum 4 mm single layer dual reinforced – a bitumen-polymer reinforced elasto plastomeric waterproofing membrane suitable for hotter climate conditions.
- silvakote® – a special highly reflective bitumen-aluminium paint for metallic, bituminous, and concrete surfaces. The product offers UV protection for bitumen systems.
- abedex HM® – a high movement reinforcing torch applied membrane.
- Malthoid 3-ply – an asphaltic waterproofing membrane with a fibre felt carrier.
- abeproof PU ECO – a flexible water-based polyurethane waterproofing membrane with excellent chemical resistance.
The methodology applied for the application by Con-Solve Civils was:
- Single-layer dual reinforced abedex® Unigum 4 mm waterproofing membrane was applied by heat fusion, with sealed 100 mm side laps and 150 mm end laps onto bituprime. The primed surface was fully bonded by “torch-on” fusion to falls and cross falls, with 50 mm x 50 mm mortar fillets on all corners, finished with silvakote® bitumen-aluminium paint. All butt joints were mirrored over the existing joints.
- Application of two coats of silvakote®.
- Counter flashing: 100 mm super laykold® with abe® membrane system was applied between the wall and the torch-on membrane and finished with two coats silvakote®.
Joints:
- Malthoid 3-Ply was loosely installed over joints.
- This was followed by the installation of abedex® HM (500 mm wide, fully bonded 150 mm on either side of the Malthoid only).
Ring Beam:
On completion of the heat-fused abedex® Unigum 4 mm system, the next phase involved waterproofing and repair of the large concrete ring beam using abeproof PU ECO. This also involved repairs to the beam scupper outlets where necessary.
abeproof PU ECO, as stated above, is a flexible single-pack water-based polyurethane seamless liquid waterproofing membrane that is fast drying and has excellent chemical resistance properties.
The domed roof waterproofing was completed and was accepted by Umgeni Water.
Subsequent to this, the Umgeni Water Technical Team and Project Manager then indicated that a phase of the overall Reservoir No 3 project involving the installation of a new lining system. Upon inspection of the existing joints and bandage system in the reservoir, it was discovered that several of the joints required repair.
The Umgeni Water team requested an assessment and methodology for the internal joint repairs. Tenders were called for and Con-Solve Civils was subsequently also awarded the work.
a.b.e.® was also asked to provide a technical specification for the remedial work and duly submitted that removal of the old vulcanised system was to be removed where needed and prepared for the durajoint flexband high-performance waterproofing bandage system. This system repairs and seals expansion, construction and contraction joints in concrete.
Floor Execution:
The a.b.e.® products involved in this phase of the project are:
- durajoint flexband (composed of functionalised thermoplastic elastomers) 300 mm x 2 mm system over the main joints – a total of 1980 linear metres.
- duraband 170 mm (polypropylene, specially coated non-woven waterproofing tape with high-pressure resistance, excellent lateral and longitudinal elongation) over the upstand joints – 680 linear metres.
- epidermix® 318 epoxy adhesive (a solvent-free polyamide cured epoxy adhesive for repairing and patching defects in concrete). A total of 1244 litres was supplied.
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 specified. This is a unique product that can be applied in submerged conditions, capable of handling positive and negative water pressure, yet at the same time performing two significant and vital functions:
The Works is a scypolymer adhesive; and is also a sealant with a 50% movement accommodation factor (MAF).
The application of The Works by Con-Solve Civils was extremely successful and alleviated the problem of water ingress yet allowed for the bandage installation thus preventing interruption in the joint remedial work throughout the reservoir internally. A total of 1071 cartridges of The Works was installed.
The internal joint work was completed successfully on time involving the repair of all joints.
However, while the joints were being attended to, it was discovered that the drainage outlet chamber, as well as associated concrete wall structures also required attention. It was immediately indicated that these concrete substrates needed the application of duraflex®, a flexible cementitious system that was brush-applied without the use of a membrane – which represented a unique use of the product.
External Work:
Umgeni Water required that the external upstand walls of the entire reservoir structure be addressed as well as the dish drainage channels, including the butts to the surrounding reservoir concrete pavement.
To repair the vertical face of the radial concrete pavement – from the top of the U-channel to the side elevation of the pavement – a.b.e.® specified the use of the following of its products:
- duraband 170 mm (340 linear metres)
- epidermix® 318 (336 litres)
- duraflex® (42 x 15 kg boxes)
The installation of this installation is exposed, therefore it is UV stable.
The external reservoir walls were assessed and the following was specified:
- Wall joints were rehabilitated using duraband.
- The entire external wall structure was coated with silocoat which is a two-component polymer-modified cementitious coating (15 kg x 536 boxes).
Important benefits of the use of silocoat as the specified protective coating included:
- 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.
- Effective barrier to sulphates and chlorides and low pH
All the above extensive remedial work on the reservoir was completed within the stipulated program requirements. Con-Solve Civils deserves credit for successfully completing the project with the full bouquet of a.b.e.® products on time – and with an exceptionally high level of professionalism.
MOTIVATION FOR ENTRY BASED ON YOUR CRITERIA:
- Construction innovation technology
Negative water pressure through the concrete joints at the time of repair could not be sealed with traditional sealant systems. Therefore, a.b.e.®’s innovative product The Works was specified for this project. This superior construction sealant and adhesive handles applications impossible with traditional solvent or water-based adhesives.
The Works can be applied in wet or dry conditions on virtually any substrate to achieve a secure fix without shrinkage, staining, or solvents, with no need for additional fixings for most applications. It resists mould growth, is flexible and over-paintable. This unique sealant saved time and money for the client eliminating the need to dewater the 340 mega litres reservoir or wait for the water table to drop for ground water to not seep through. The Works is also a primerless sealant, which offers a lower labour-intensive solution.
Furthermore, another a.b.e.® eco-friendly product, abeproof PU ECO, was used for concrete rehabilitation and protection and aesthetical finish and waterproofing to the main concrete ring beam of the reservoir. Certified environmentally friendly with a reduced carbon footprint (3740 litres of product / 130 900 sq m covered), the product was spray-applied to also reduce labour requirements.
- Corporate Social Investment
a.b.e.® is part of Saint-Gobain, who have been building their commitment to climate change for several years, both through the impact and effectiveness of solutions and through action to reduce emissions from industrial processes.
Our social commitment is an essential source of sustainability, particularly in terms of attracting and retaining talent.
Our goal is to make a positive contribution to environmental, social and societal issues.
Saint-Gobain and its brands’ exemplary role in the territories where we operate, our actions to promote employment and training in the communities around us, and the commitment of our teams within the Saint-Gobain Foundation, are all examples of how we participate in building a fairer and more sustainable world.
Con-Solve Civils continuously launch projects that contributes to social upliftment and the same at the Durban Heights reservoir project, with local employment and upskilling. Con-Solve Civils, a core contractor at SAPREF, did conform with CPG requirements and local employment.
- Design Innovation
The reservoir is an existing structure that required remedial repair, protection and waterproofing that offers superior and cost-efficient solutions ensuring long-term serviceability.
- Environmental Impact Consideration:
The project ensured the continuation of the supply of drinking water to at least 500 000 members of the population and was an integral part of the complete water articulation for KZN fresh water supply.
- Health & Safety:
To ensure safe work procedures to mitigate, reduce or control the hazards identified, ISO 14001 and 18000 standards were followed strictly and site inductions were completed. Access control was important and enforced.
- Quantifiable time, cost and quality:
Because the project involved specialised repairs, the quality of the product and workmanship were crucial and inspected regularly. Time also was a vital factor in getting water to the communities as soon as possible.
- Risk management:
The harmful vapour of products was eliminated by the use of non-toxic products such as epidermix® 318. All necessary safety procedures were also followed during working at heights, scaffolding, lighting, PPE, and clearance procedures while working in a confined space.
- Motivation facts about the project:
a.b.e.® is a manufacturer and major supplier for over 90 years of specialized construction, concrete repair and protection, waterproofing, flooring, sealant, and adhesive product systems to the building, civil, and maintenance industries – with vast technical knowledge and expertise.
Together with Con-Solve Civils, a specialist contractor in the industry, and the asset owner Umgeni Water, close cooperation and a good relationship were also important for the successful completion of the critical rehabilitation of this infrastructure – 340 megalitre structure built in 1971, one of the largest potable water storage facilities in South Africa.
The remedial solutions and installation provided substantial savings to the client, notwithstanding preserving water supply to a large number of households, businesses, and industries in and beyond eThekwini, Kwa-Zulu Natal.
Project Information
Company entering: a.b.e.®
Client: Umgeni Water
Start date: November 2021
End date: April 2023
Main contractor: Con-Solve Civils
A wide variety of specialised a.b.e. products was used, including removal of the original torched membrane system
New waterproofing specification is based largely on abedex unigum 4 mm bitumen-polymer reinforced plastomeric waterproofing membrane system
Single-layer abe 4 mm waterproofing membrane was applied by heat fusion, on bituprime primed surface and coated with silvakote
Concrete Repair and protection of external upstand walls as well as the dish drainage channels
Remedial repairs included domed roof, ring beam & amp; joints waterproofing, as well as external walls and internal floor & amp; joint repair & amp; protection