In pursuit of sustainable infrastructure development


Concrete continues to play a pivotal role in economic growth both locally and globally. As infrastructure investment and development across Africa take on a new sense of urgency, the construction industry is recognising that a different approach is required on and for the continent however, and that we can't simply take textbook-type economic models and apply them across this diverse space if we're committed to taking a long term view of sustainability. Africa's context demands that we innovate across the full value chain - from planning right through to design, construction and building management. As such, much of this sustainable innovation will have to do with the use of concrete as a building material.

In order to improve the sustainability of concrete structures, one has to understand the interdependencies from 'cradle to grave' in the design phase, during construction and at end-of-life and, most importantly, how these influence the eco-impact and the carbon footprint of structure during its life cycle. 'While the industry has worked to quantify the 'embodied-energy' impact of materials used in infrastructure development, effectively measuring the 'whole-life' impact and full effects of the infrastructure's existence during its usage phase continues to challenge the industry,' notes Daniel van der Merwe, Architect: PPC Ltd. 'This type of measurement is however critical if we're to meet future targets of 'zero net-energy' buildings. Understanding the life-cycle impact of concrete is therefore central to this equation.'

Due to its flexibility and durability concrete is the most widely consumed substance on earth after water, with approximately 12 billion tons being created globally annually. Cement is a constituent of concrete (approximately 10 - 15% by volume). 'The energy used in cement production is a key component of the environmental impact of cement manufacture due to the high kiln temperature involved in production,' explains Alta Schoultz, Head of Innovation: PPC Ltd. 'This must be viewed in context however.'

Globally, cement manufacture accounts for approximately 5% ofgreenhouse gas emissions. 'The industry has already reduced its carbon footprint by reducing the use of non-renewable fossil fuels, by introducing more modern technology and equipment and introducing alternative cementitious materials,' says Schoultz. 'This includes the use of alternative fuels and resources in kilns, including waste tyre-burning.'

'To effectively reduce the carbon impact of the built environment at the lowest cost, the industry will have to innovate together if we are to positively redefine the continent's future and root its development in sustainability,' says Schoultz. 'This makes it important for each user group to understand specific concrete benefits for them.'

From an ownership perspective, concrete offers technical advantages, aesthetic appeal and cost effectiveness. Its strength, durability and natural thermal mass can assist in developing buildings that are low maintenance, durable and have high operating energy efficiency. 'Developers on the other hand can make use of concrete as a competitive building solution. This is based on first cost, long term economic benefits, energy efficiency, lower maintenance, and overall operating costs, as well as opportunities for future reuse should the occupancy of the building change,' notes van der Merwe.

He adds that concrete is an ideal medium for designers - offering a range of colours, finishes and unlimited design possibilities, difficult to match in other materials. 'The resultant structure also provides superior environmental and energy performance. The benefits of designing with concrete to leverage its thermal mass and structural integrity can be seen in many award-winning projects throughout the world.'

Connecting user groups to leverage technical expertise and insights from the outset can however prove a challenge, explains Schoultz - which is why PPC developed an industry collaboration platform just over a year ago. 'The Cement and Concrete Cube or C3 is the first non-commercial, open, information sharing platform in the cement and concrete industry in South Africa. It facilitates communication among industry players, including industry news and trends, research, studies and findings, and sources of inspiration. In this way, it enables more effective collaboration across the value chain.'

With the development of sustainable infrastructure in the country and on the continent coming under the spotlight at the Green Building Council of South Africa's (GBCSA) annual convention in November, Schoultz says it's an ideal time for players in the construction space to rethink a strategy for future projects. 'Sustainability is about far more than singular aspects of materials only. It involves taking a long term view of any development such that one considers both the best interests of people and the planet. Finding this balance will require far more conscious and responsible choices from all of us - and we're looking forward to engaging in this type of conversation at GBCSA's conference this year.'

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