ER57MG Balfron Tower on the Brownfield Estate in Poplar: East London. Photograph: Anthony Palmer / Alamy Stock Pho/Alamy Stock Photo
This week Guardian Cities has been investigating the contentious issue of concrete. While it has brought about improvements in public health and some celebrated works of architecture, the material is causing widespread destruction across the globe.
As our coverage explored concrete’s different angles – its environmental impact, its influence on culture, the brutalist buildings under threat, and potential alternative materials – many of you joined in the debate.
We were overwhelmed by your response, from photos of your favourite concrete beauties and detested monstrosities, to tales of how concrete has shaped your cities, such as this Instagram post from the Birmingham Civic Society about the legacy of its “concrete collar”.
On Twitter there was an impassioned debate over whether the demolition of Birmingham’s old Central Library – a former brutalist landmark – was architectural vandalism or the right decision for the city.
You also expressed alarm at the dangers that the production and use of concrete is posing to the planet, and several of you, inspired by Fiona Harvey’s report on alternatives to concrete, shared examples of more environmentally friendly materials and methods.
Concrete’s environmental impact
Jonathan Watts, the Guardian’s Environment editor, kicked off our Concrete Week with an in-depth report on the shocking impact of concrete on the planet. Here’s a selection of your many responses to his report:
Jonathan this article is brilliant. Terrifying and overwhelming but a powerful, informed argument for radical change when it comes to design, architecture and our built environment. Thank you.
— Finn Harries (@FinnHarries) February 25, 2019
Great thoughts on concrete. A useful, beautiful material that reduces the environment to feed a corruption juggernaut. From @guardiancities https://t.co/DwWgjohIVL
— Matthew Populus balsamifera trich. Shields (@MattGShields) February 27, 2019
It's not just a infrastructure struggle, it's a mindset one. Breaking the #concrete hold will require us to change the way we view the 'built environment'. #nature #GuardianConcreteWeek #climateaction #LocalWisdomhttps://t.co/05JbssRkhZ
— Vijayalakshmi V (@vijiv15) February 25, 2019
Alternatives materials
Fiona Harvey reported on the new alternatives to concrete being developed, such as cross-laminated timber. David Hopkins, managing director of the Timber Trade Federation, got in touch to reiterate the benefits of wood: “There are lots of advantages to building in timber – managed forests provide a range of environmental benefits, helping to produce oxygen, provide biodiverse habitats and natural management of water, reducing flood risk. As a material that absorbs rather than emits carbon, timber continues to make a positive contribution to the environment after it is harvested, and has one of the smallest carbon footprints of any material used for building.”
Other readers told us about other potential solutions we’d missed.
Hemp – perhaps not commonly associated with the construction industry – has long been celebrated as an alternative building and insulation material. “Hempcrete” is made with a mix of hemp hurds, lime and water, and is used mainly for non-structural building materials and wall insulation. Once the plant is turned into hempcrete it continues to absorb CO2.
Straw is another option. Straw Works, for example, manufactures pre-fabricated straw panels. The company says: “Load bearing walls are either built of load bearing straw bales, or timber frame infilled with straw.” As an alternative to concrete foundations it is also using car tyres for the new community hall by Holy Trinity Church in Tulse Hill, London.
We also heard about Gnanli Landrou, a scientist and entrepreneur, who is developing a process to turn clay-based excavation material into a soil-based concrete, which doesn’t use cement – the key material that is most responsible for concrete’s shocking carbon footprint.
Its Concrete Week! Considering concrete is the second most used material after water, it is critical to understand the ramifications of current production methods and push for more sustainable alternatives. #GuardianConcreteWeek #CircularEconomy https://t.co/G0Xyi2FSRh
— Natalie Carr (@natschybatter) February 27, 2019
Reducing pollution
You contacted us to tell us about cement companies that are attempting to make the production process less harmful to the environment. The manufacture of clinker is the most-energy intensive part of cement production, with half of concrete’s CO2 emissions created during this process. Dalmia Cement, Ambuja Cement and UltraTech Cement in India say they are trying to change the way they produce clinker, and are using recycled industrial waste. They use low-grade limestone, with fly ash (waste from thermal power plants) and slag (waste from the steel industry) in their blended cements.
One reader on Twitter also said:
Your should check out CO2LOC technology at #camcarbcap - captures CO2 from concrete production and the by-product can be used in the ready mix or replace gypsum with an environmentally benign and fire@proof alternative - ‘Clean Concrete’ is our future. #GuardianConcreteWeek
— Michael Evans (@MichaelCO2Cap) February 26, 2019
Structural engineer Nawid Daoud, meanwhile, argued that – although he supports sustainable alternative materials – some elements of construction can’t be done using sustainable, commercially viable alternatives (yet). He says for certain components of buildings, concrete is still the most viable option both from a material strength perspective, and from a cost perspective.
For example, the vast majority of building foundations are concrete, and you will struggle to find an alternative, more sustainable material which will perform in the same way as concrete does under intense compression, let alone one which is widely available (and therefore affordable).”
Concrete and architecture
You took to Instagram to post concrete-inspired photos, and wrote about your affection for certain concrete structures.
And spare a thought for the concrete mixer drivers
Mark Cowan from UK Truckmixer Training got in touch to flag up the importance of training for drivers who deliver concrete. Cowan, who has worked as a concrete mixer driver for 28 years, says these vehicles are frequently subject to rollover incidents.
Last but not least …
… we received this photo of concrete hippos in Glenrothes, Fife.
Milton Keynes May have its cows but Glenrothes has concrete hippos! #GuardianConcreteWeek #glenrothestownart pic.twitter.com/lBPWsEaoGr
— Andrew Demetrius (@Demetrius_Art) February 26, 2019
Thanks to all of you who submitted comments, emails, tweets, posts and images. We looked at each one, and although we couldn’t include them all we were hugely heartened by your passion and knowledge. Our belief with Concrete Week was that people could care about concrete – and we were thrilled to confirm that so many of you already did.
Guardian Concrete Week investigates the shocking impact of concrete on the modern world. Follow Guardian Cities on Twitter, Facebook and Instagram and use the hashtag #GuardianConcreteWeek to join the discussion or sign up for our weekly newsletter
