Sustainable materials: is there a concrete solution?

[Music] storms ravaged cities around the world the new york city subway system shut down the city received over 200 millimeters of rainfall the highest since 2015. as the climate crisis worsens extreme weather events are becoming ever more common and these concrete jungles aren't exactly helping infrastructure is impermeable so often you get flooding because the water's got nowhere to go in fact the industry that builds this infrastructure is making things worse eleven percent of the world's carbon emissions come from construction we cannot afford to carry on business as usual in two years china poured more concrete than the usa did in the whole of the last century so how can humans build without it costing the earth we have three kids we have their futures to think about our future to think about [Music] nareed and mozamel and their three kids live in the bay area of san francisco they bought their house three years ago but now with a growing family they need more space i'm thinking that in order to give us more space in our bedroom we just build out eight feet this way when we bought the house we had really grand plans to add a thousand square feet and make it a huge home and then we spent some time researching and analyzing and really going through it there's a lot of good things about living with less there's less cost for heating and cooling but then that impact on the environment we really made a conscious decision we've now scaled it back to about 100 square feet so we're headed to the primary bedroom we don't have a ton of closet space so really only my things fit in this bedroom whereas mizzy's things are actually out in the hallway the environment has always been close to mozamel's heart we can go out from the back something he made clear to nareed on their very first date i told her she was perfect except for the fact that she didn't recycle and it was understandable that she didn't recycle she explained to me because she lived on a four fourth floor walk-up that had an opera white side of manhattan that had foot ceilings so every time i had like one bottle living as a single person i'd have to go down four flights of stairs to take it into the recycling so he made me invest into a recycling container that he then would take out yes once a week i got the exercise at that point the couple's plan to extend their home may now be more modest but they're just as determined that the work does as little harm to the environment as possible and there's one very familiar material that really concerns them this one factory is now turning out 15 000 concrete slabs enough for 35 houses every week it seems like concrete's been around forever it was the romans who first started using it for everything from aqueducts to the pantheon today it is the second most used resource on the planet after water the big users of concrete at the moment are countries like china and southeast asia i've seen reports that in two years they poured more concrete in china than the usa did in the whole of the last century and of course that's associated with huge carbon emissions at imperial college professor chris cheeseman is an expert in all things concrete concrete is an amazing material if you think about what it does we take a grey powder we mix it with some aggregate stones basically and some finer sand type materials and we mix those with water and it's flowable you can pour it you can make it into a shape and then like by magic it turns into a rock the grey powder is cement it's the all-important glue in concrete but it's the biggest culprit when it comes to carbon emissions the five billion tonnes of cement produced each year account for eight percent of the world's man-made co2 emissions among materials only coal oil and gas are a greater source of greenhouse gases helsinki finland this unassuming city has an ambitious target becoming carbon neutral by 2035 and is already a global leader in climate-related technology innovation researchers here have taken up a seemingly impossible challenge to make concrete without its most problematic ingredient cement business worldwide simply cannot continue at the current rate we must find new sustainable means through innovation and technology materials technology company betola has spent five years working on an answer inspiration for the company's cement-free solution came from the mountains of waste being produced by other industries using artificial intelligence it analyzes local industrial waste and generates the right recipes to produce its composite cement alternative we take industrial waste for example from steel production and we combine it with alkali activating solution and by this way we can reduce the co2 emissions of concrete raw materials even up to 80 percent as well as this potentially huge reduction in the scale of emissions there are other obvious benefits to using waste products or side streams by providing the possibility to use the side streams we are actually giving a new life for this waste instead of landfilling into the environment it's an ingenious solution but even given the extent of industrial waste questions remain about its scalability although the steel industry is a huge industry in comparison with concrete production it's relatively small there's just not enough waste materials they're not going to transform construction in the way that we might want to transforming construction might instead mean weaning the industry of its reliance on concrete altogether in this english county 25 new houses are nearing completion it looks like a fairly traditional residential building site but behind these walls it's anything but [Applause] hemp it's not generally used in construction and that's got some quite unique properties hemp is another name for a very familiar plant with a colourful history [Music] but unlike cannabis industrial hemp contains only tiny traces of the chemical that gets people high it has some other things going for it though it grows incredibly fast its fibres are also surprisingly strong what we're doing here is using the woody core of the plant which is called shiv and we're just mixing it with lime to make a rigid insulation material it's fire proof it also has fantastic thermal inertia so when external temperatures fluctuate up and down the internal temperature of the house stays very constant it's just generally a good insulator and it's locking up carbon this is about 300 square meters so if you scale that up this house if it was built in a conventional way would be responsible for somewhere between 150 and 200 tons of co2 emissions we're able to get that to zero so that's a massive carbon saving at the construction stage as well as the fact that it will be operationally zero energy going forward as well hemp used in this way can clearly help deliver significant reductions in carbon emissions but its nickname hemp crete might be a little misleading it's an interesting material but you're not going to build major infrastructure out of hemp feet you might build an extension or even a house out of heavy creek but it's not going to compete with concrete as we know it because it just doesn't have the mechanical properties and strength and durability probably as well here greencore isn't working with hemp alone though it's building with wood and as the search for sustainability grows so does the revival of interest in the potential of this age-old material at cambridge university's school of architecture michael ramage and his team are taking inspiration from the past to inspire the construction industry to new heights in the future oakwood tower was a demonstration project and a research project to show that building really tall in wood was possible so we engineered this 300 meter tower for central london and we showed that it was possible for it to stand up whilst oakwood tower is just a proof of concept it's based on innovations that have transformed the load-bearing strength of wood in the last few decades a new category of engineered timber has emerged in particular cross-laminated timber which are very big engineered materials made of wood that are strong and they can be used as replacements for steel and concrete in buildings of all sizes clt is constructed in a controlled factory environment by gluing layers of wood at 90 degrees to each other the layers are then hydraulically pressed together creating high strength structural panels using computer controlled joinery machines any shape of panel can be cut before being transported to site timber building sites tend to be much quieter than other building sites because they go together mostly with battery-powered drills construction is much quicker because the timber arrives on site pre-fabricated like flat pack furniture and it gets lifted into sight by a crane while high rises are lots of fun to design and an interesting challenge to engineer most of the buildings that we need are not high rises and are ideal for building in cross-laminated timber but one thing everyone knows is that wood burns for many fears would be fueled by the prospect of wood-built cities going up in flames cross-laminated timber is is of course wood and it will always be a combustible material but we know how to make fire-safe designs in cross-laminated timber there are a range of different strategies so that fires don't spread if they do start and so that the wood in many cases is not exposed to the fire it's often behind layers of plasterboard but one of the big challenges with wooden buildings is that the wood is lovely to look at and architects and clients and engineers want to expose the wood as much as possible and that is a challenge for the fire safety so making those two aspirations work together is something that all of us i think in this area are working on and hoping to solve in 2018 55 of the world population lived in urban areas and that is expected to grow to 68 by 2050 they will need homes to live in offices to work in and more of the infrastructure people rely on the construction industry's got its work cut out and it faces a monumental effort if it's to become truly sustainable as well as novel use of old materials from industrial waste to hemp or timber more new solutions are going to be needed every company out there is pushing the green agenda i think the pull is really coming from the customers people want low carbon buildings now there's a big big pool for that rather than doing the things we've done in the past i think designers and architects need to look at how we use materials so that they're used in a way that gets the most performance out of them and we don't waste materials see it depends when we build it out and for people like massimo and neureed it always comes down to the same thing money being green isn't cheap i think for folks like us where you have limited funds but understand the morality of making these choices i think we frequently run up against what's at all worth and justifying spending more money in order to uphold our values i'm john fassman the economist u.s digital editor to keep up with all our climate change coverage click the link thanks for watching and don't forget to subscribe you

Channel: The Economist

Views: 199,607

Keywords: The Economist, Economist, Economist Films, Economist Videos, Politics, News, short-documentary, sustainability, concrete, building materials, building materials and construction, eco-friendly building materials, basic building materials, construction, green building, architecture, building, green architecture, buildings, environment, climate change, what is sustainability, sustainable

Id: QnN4pZtf7aE

Length: 13min 22sec (802 seconds)

Published: Tue Mar 22 2022

Reddit Comments

[u/ale_93113]

Hardly

You can build houses, yes, but our aim should be for 4-10 story medium density like Paris, Amsterdam or even the 3 stories of Montreal, which although can be done without concrete, it's very hard to do

Urban area consumes a lot more concrete, our priority should be to debsify cities and reduce urban area if we want less concrete to be used, not on the buildings themselves

[u/ScythianUnborne]

Essentially, Hemp and Wood are the solutions to this. The problem, though, with wood, is deforestation. We have to veer away from concrete and cement, certainly, but what material should we go to that is sustainable enough where we can grow it everywhere, without threatening ecology, or damaging the environment? Seems to me like it just might be hemp.