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Maintain and repair the old before placing new concrete, materials expert urges

There is an urgent need to address the deep water and sanitation crisis with which the country currently grapples. The cement and concrete value chain has a large role to play in augmenting water supply. However, this must but be done in a sustainable manner.

This is the view of Dr Rod Rankine, a construction materials specialist. Dr Rankine addressed the many built-environment professionals who attended Cement & Concrete South Africa’s (CCSA) Concrete Working for Water Roadshow. The event brought together built-environment professionals to unpack the extent of the water crisis; find solutions; and mobilise action.

He noted that sound water-security planning started with maintaining existing infrastructure. Considering the extent of decline of water-supply assets, with many having fallen into a serious state of disrepair, this is a significant undertaking that bodes well for the South African cement and concrete supply chain. A durable, versatile and cost-efficient construction material, concrete has remained the preferred choice for water and sanitation infrastructure. This includes dams, water and wastewater-treatment plants, storage and conveyance systems.

Currently, 42% of the bulk infrastructure assets held by the Department of Water and Sanitation’s Water Trading Entity are in poor condition. Yet, it only spends 2,13% of the total infrastructure assets on repair and maintenance. This is despite the National Treasury’s prescribed 80% norms and standards for maintenance. Worryingly, it has been found that the department has no policy in place to guide the maintenance of its water-supply assets.

While 96% of the South African population has access to infrastructure, only 85% of these assets are operational. At a national level, just 65% of this infrastructure provides a reliable service. In the rural areas, the functionality of water infrastructure is much lower. Only 40% and 39% of infrastructure operate as intended in Limpopo and Mpumalanga, respectively. In other provinces, just 20% of municipal water service-delivery assets operate at efficient levels.

Presenters at CCSA’s Concrete Working for Water Roadshow agree that failure to maintain existing infrastructure is the root cause of South Africa’s water supply dilemma. Dr Rankine noted that focus of service delivery is only on the construction of new infrastructure with scant regard given to its other critical components, namely the management of the assets throughout their service life. He referred to research undertaken by Professor Kevin Wall of the Department of Construction Economics at the University of Pretoria that demonstrates the many benefits of appropriate infrastructure management. When infrastructure is maintained timeously, the long-term cost of service delivery declines significantly. Over a

period of years, this approach relieves funds for new infrastructure. He quotes Prof Wall as saying, “Delivery needs to be understood as embracing not just the construction of infrastructure, but the management of the infrastructure throughout its intended life.”

However, it is not only South Africa that is struggling to keep pace with maintenance demands. It is a worldwide problem, which is anticipated to grow, according to Dr Rankine. He pointed to the forecasts contained in Limits to Growth: a 30-Year-Update, authored by Donella and Dennis Meadows and Jorgen Randers. Commissioned by the Club of Rome, the study discusses the possibility of exponential economic and population growth with finite supply of resources, studied by computer simulation. According to the authors of the updated report, “by the middle of this century, investment in industrial capital will no longer keep up with depreciation.” Europe’s aging infrastructure made international headlines in August 2018 when a highway bridge collapsed in Genoa, killing 43 people. Ireland’s railway transport system has been neglected to such an extent over the years that it is becoming unsustainable to operate.

Further compromising water-security is the notable decline in the quality of new water infrastructure and design and construction, especially at municipal level. This casts a shadow of doubt over the ability to deliver the top-notch concrete infrastructure required to supply water. It also brings the entire cement and concrete industry into disrepute.

Dr Rankine said glaring inaccuracies in simple concrete application techniques have rendered new water-retaining structures unusable. This dire situation is contributing to wasteful expenditure of already-stretched government resources, further threatening the sustainability of the country’s water-supply system.

He pointed out that the cost of adequate prevention during design is minimal compared to the cost of rehabilitation at a later stage.

Dr Rankine cited part-time Professor in the design of concrete structures at the Eindhoven University of Technology, Wolter Reinold de Sitter’s proposed Law of Fives for structural concrete maintenance as an example. According to Prof De Sitter, R19 spent during design and construction is as effective as spending R95 after the structure has been built, but corrosion is not yet evident; R475 when it has started at some points; and R2 375 when it has become widespread, and rehabilitation is required.

“If we really are going to invest in new infrastructure, it should be designed well and built to last as long as possible. An appropriately designed and -built concrete reservoir should last for no less than 100 years,” he said.

Dr Rankine said that it was important to understand that the construction of new water infrastructure would not solve South Africa’s water crisis if proper demand management was not implemented. Average domestic water use is estimated at 237ℓ per person per day. This is 64ℓ more than the international benchmark of 173ℓ per person per day. Considering that South Africa is a water-stressed country, robust demand management is important to ensure equitable and sustainable use of this resource.

“There are biophysical limitations that need to be taken into consideration when planning water-augmentation projects. Freshwater is a finite resource. If we supply more by constructing additional water infrastructure, people will simply consume more of it, and this is not a sustainable solution. This is not to mention the impact that additional water-supply systems will have on our water-supply infrastructure maintenance backlog problem, which has reached critical levels,” he said.

Dr Rankine warned that complex service-delivery infrastructure is subject to the laws of diminishing marginal returns. All previous sophisticated societies, including the Egyptians, Incas, Mayans, Romans and Greeks, collapsed because their survival depended on unsustainable methods of capturing energy. “Why should our destiny be any different if we continue on exactly the same path? Ernst Mayr, the American biologist, implied that intelligence is a lethal mutation, and that successful species were able to adapt and mutate quickly. They may survive, but as they become more intelligent, they are less successful. Meanwhile, the renowned South African Professor of Geochemistry, Terrence McCarthy, warned that we are becoming increasingly specialised. He is quoted as saying, ‘Palaeontological record warns us that specialisation leads to vulnerability. Our civilisation sits on a knife edge’. I have to agree,” he said.

A fundamental component of the service-delivery infrastructure backbone, South Africa’s water system is already on the verge of collapse. The under-pricing of water use contributes to the total losses experienced by the system. To ensure financial sustainability of water infrastructure, South Africa requires tariffs that are closer to cost-recovery levels. However, a large portion of the population lives in multi-dimensional poverty and, therefore, cannot afford this most “basic human right”. As such, revenue collected for water use is significantly lower than the actual value of the assets. This makes investing in new water-supply infrastructure unsustainable. Meanwhile, non-revenue water accounts for as much as 36,8% of losses to our water-supply system, again placing a spotlight on the extent of poor maintenance practices of water-supply systems.

Dr Rankine also questioned the accuracy of forecasts in future increases in water demand that are modelled on population growth rates. These inform the planning of future

“brownfields” and “greenfields” water infrastructure projects. The Department of Water and Sanitation estimates that about R90-billion per year must be invested in new water and sanitation infrastructure to address the crisis.

He said that Africa is the only continent that is experiencing exponential population growth. While the African population is expected to number 4-billion by the middle of this century, Dr Rankine said that this is not a given. For example, population growth in the Global North has slowed and even declined in many countries. In 2023, US excess deaths were 40% higher than the historic mean average – a “10-sigma event”. Meanwhile, the excess mortality rate since the outbreak of COVID-19 has not reversed in the US and UK as expected. “The world population cannot grow forever. A world population of 1-billion to 2-billion people is deemed sustainable. We only need an annual 2% surplus of death over births to achieve this by the end of the century,” he concluded.