When a national newspaper publishes a 4500 word feature questioning the value of concrete, should it feature structural engineers prominently? I would like to think so. Our profession is responsible for design, specification and construction of much of society’s concrete - either in our own right or collaborating as part of a project team - and we play an important role ensuring the material is used in a responsible manner.
So I was disappointed that an opportunity for prominence for engineers was ‘stolen’ by others – and by politicians! Indicative was the number of mentions: engineers 2 politicians 7. That is a bad result – even worse when we are at home playing on our own turf.
Consider the context
The article focuses on the ills of development and the corrupt nature of power. There is nothing wrong with placing a spotlight on those, but I hoped, as an engineer, that it might take more trouble to tell the story of how engineers and architects use concrete to deliver a society of safe housing, clean water and resilient infrastructure – with all the challenges, successes and failures involved.
Why we use concrete
Seeing the article headline a member of the public might well ask: “why do we still use this material?” The answer is pretty simple: so long as there is development, concrete is usually the best material we have to deliver a safe, durable structure.
It is also locally available, cost-effective and there is no other material that can be produced in the volumes required for the scale of development that society currently demands. Additionally, it is versatile both in the mix of constituents and the form that it can be cast into.
It has inherent properties of fire resistance and resilience against rot, infestation and rust. Designers can utilise these properties to deliver infrastructure and building projects that meet the performance demands of developed and emerging economies.
What engineers can do
It’s perfectly fair to ask questions about the scale and pace of development around our planet. What we can say as a profession is that sustainability and climate change implications of the industry are well understood:
Responsible sourcing
Engineers can ensure specification of responsibly sourced materials. Construction products are no different from consumer products, in that the purchaser (and specifier) has the tools to lever producers to raise environmental and social standards.
Sustainable specification
More specifically in the context of concrete, engineers can carefully specify the cementitious content and aggregates. By utilising by-products of iron ore production and coal fired power stations, as well as limestone cementitious fines, the carbon impact can be reduced and properties enhanced.
These also increase the recycled content of concrete, as can careful specification of recycled and secondary aggregates.
For more on sustainable specification of concrete constituents see previous briefing notes on “Cementitious Materials” and “Recycled and secondary aggregates in Concrete”.
Innovations in admixtures
We can work with concrete technologists and utilise innovations in admixtures, as previously discussed in The Structural Engineer.
Maximise resource efficiency
Beyond material specification, engineers can also seek to maximise resource efficiency. This is in terms of designing structurally efficient forms and optimum utilisation of elements, cross purposing of structure with other functions (partition, cladding, ceiling) and consideration of “long-life loose-fit” and/or design for demountability.
Operational energy
Operational energy remains the largest part of most building’s footprint. This will remain critical even in a decarbonised grid since the generation and distribution of renewables does not come for free.
As structural engineers we can work with others to utilise the structure to reduce energy demand and (for some build types) reduce the likelihood of future air conditioning retrofit.
This may be use of a more solid façade as structure or utilisation of thermal mass for which a brief introduction can be found here.
Making the argument with clients
And there is so much more: clients and letting agents often demand our buildings are constructed for floor loadings that are unnecessarily high. We need to challenge such requirements and argue for more efficient use of resources. But that is worth a whole blog on its own…
Conclusion
Engineers can help solve the challenge of meeting societal demands for infrastructure and buildings that are safe and durable whilst minimising whole life impacts. The Institution of Structural Engineers and its members have started on that journey but, like society at large, we have more to do.