Displaying items by tag: Demolition

Cement and concrete products with sustainability credentials have increased in recent years as societies start to demand decarbonisation. In spite of the recent drop in the European Union (EU) Emissions Trading Scheme (ETS) price, there has been a trend in recent years in the construction industry towards offerings with better environmental credentials. Indeed, this week’s position paper from Cembureau on a carbon border mechanism concerns directly the growth of these kinds of products within Europe. Typically, the higher profile projects have been slag cement or concrete implementations such as Hanson’s use of its Regen cement substitute in a London sewer project or David Ball Group’s Cemfree concrete in a road project also in the UK. In this short review we’ll take a selective look at a few of the so-called low carbon cement and concrete products currently available.

Table 1: Some examples of methods to reduce embodied CO₂ in cement and concrete. Note - the product examples are selective. In some cases many other products are available.

Looking at cement first, the easiest way for many producers to bring a lower carbon product to market has been to promote cements made using secondary cementitious materials (SCM) such as granulated blast furnace slag or fly ash. These types of cements have a long history, typically in specialist applications and/or in relation to ease of supply. For example, cement producers in eastern India often manufacture slag cements owing to the number of local steel plants. However, cement producers have more recently started to publicise their environmental credentials as they reduce the clinker factor of the final product. Alongside this though, in Europe especially, a number of so-called low carbon cement producers have appeared on the scene such as EcoCem and Hoffman Green Technologies. These newer producers tend to offer SCM cement products or other low carbon ones built around a grinding model. It is likely that their businesses have benefitted from tightening EU environmental legislation. How far cement producers can pivot to SCM cement products is contentious given that slag and fly ash are finite byproducts of other industries that are also under pressure to decarbonise. Although it should be noted that other SCMs such as pozzolans exist.

As will be seen below a few of the methods to reduce embodied CO₂ in cement and concrete can be used in both materials. SCMs are no exception and hold a long history in concrete usage. As mentioned above David Ball Group sells Cemfree a concrete product that contains no cement. Harsco Environmental, a minerals management company, invested US$3m into Carbicrete, a technology start-up working on a cement-free concrete, in late 2019.

Limestone calcined clay cements are the next set of products that are starting to make an appearance through the work of the Swiss-government backed LC3 project, more commercial offerings like FutureCem from Cementir and H-EVA from Hoffman Green Technologies and today’s announcement about ThyssenKrupp’s plans to fit the Kribi cement plant in Cameroon with its Polysius activated clay system. They too, like SCM cements, reduce the clinker factor of the cement. The downside is that, as in the name, the clay element needs to be calcined requiring capital investment, although LC3 make a strong case in their literature about how fast these costs can be recouped in a variety of scenarios.

Calcium silicate cements offer reduced process emissions by decreasing the lime content of the clinker lowering the amount of CO₂ released and bringing down the temperature required in the kiln to make the clinker. Solidia offers its calcium silicate cement as part of a two-part system with a CO₂ cured concrete. In the US LafargeHolcim used Solidia’s product in a commercial project in mid-2019 at a New Jersey paver and block plant. Solidia’s second core technology is using CO₂ to cure concrete and reducing water usage. They are not alone here as Canada’s CarbonCure Technologies uses CO₂ in a similar way with their technology. In their case they focus more on CO₂ mineralisation. In Germany, Schwenk Zement backed the Celitement project, which developed a hydraulic calcium hydro silicate based product that does not use CO₂ curing. Celitement has since become part of Schwenk Zement.

Solidia isn’t the only company looking at two complementary technologies along the cement-concrete production chain. A number of companies are looking at recycling concrete and demolition waste. Generally this splits into coarse waste that is used as an aggregate substitute in concrete and fine waste that is used to make cement. LafargeHolcim has Evopact for the coarse waste and Susteno for the fine. HeidelbergCement has EcoCrete for the coarse and is researching the use of fines. Closing the loop for heavy building material producers definitely seems like the way to go at the moment and this view is reinforced by the involvement of the two largest multinational producers.

Of the rest of the other low carbon cement methods detailed in table 1 these cover other non-Ordinary Portland Cement (OPC) such as geopolymer and calcium sulphoaluminate cements. The former are a type of alkali activated binder and generally lack common standards. The latter are similar to slag cements in that they are established specialist products with lower CO₂ emissions than OPC.

With concrete when trying to make a low carbon product the first choice is whether to choose a low-carbon cement as the binder or even not to use cement at all in the case of Regen or Cemfree. From here the next step is to simply use less cement in a concrete mixture. There are a number of ways to do this from optimising aggregate gradation, following performance specifications more closely, using strength tests like maturity methods and generally adhering to quality control protocols better to deliver more consistency. Read the Mineral Production Association (MPA) publication Specifying Sustainable Concrete for more detail on this. Using concrete admixtures can also help make concrete more sustainable by improving quality and performance at construction sites through the use of plasticisers and accelerators, by decreasing embodied carbon through the use of water reducers and by improving the whole life performance of concretes. The use of locally-sourced aggregates is also worth noting here since it can reduce associated transport CO₂ emissions.

More novel methods of reducing embodied CO₂ emissions in concrete include the use of geopolymer concrete in the case of Zeobond Group’s E-Crete or adding graphene as Concrene does. Like geopolymer cements, geopolymer concretes are relatively new and lack common standards. Products like Concrene, meanwhile, remain currently at the startup level. Finally, if all else fails, offsetting the CO₂ released by a cement or concrete product is always an option. This is what Cemex has done with its Vertua Ultra Zero product. The first 70% reduction in embodied CO₂ is gained through the use of geopolymer cement. Then the remaining 30% reduction is achieved through a carbon offsetting scheme via a carbon neutral certification verified by the Carbon Trust.

As can be seen, a variety of methods exist for cement and concrete producers to reduce the embodied CO₂ of their products and call them ‘low-carbon.’ For the moment most remain in the ‘novelty section’ but as legislators promote and specifiers look for sustainable construction they continue to become more mainstream. What has been interesting to note from this short study is that some companies are looking at multiple solutions along the production and supply chain whilst others are concentrating on single ones. The companies looking at multiple methods range from the biggest building material producers like LafargeHolcim and HeidelbergCement to smaller newer ones like Solidia and Hoffman Green Technologies. Also of note is that many of these products have existed already in various forms for a long time like SCM cements and concretes or the many ways concretes can be made more sustainable through much simpler ways such as changing aggregate sourcing or working more efficiently. In many cases once markets receive sufficient stimulus it seems likely that low carbon cement and concrete products will proliferate.

Global Cement is researching a market report on low carbon cement and concrete. If readers have any comments to make please contact us at This email address is being protected from spambots. You need JavaScript enabled to view it.

Here’s a fun idea: providing building materials as a service. Instead of the owner of a building possessing all the materials in it forever, they simply rent them. It would be like a music or television streaming service. A ‘Netflix’ or ‘Spotify’ for the construction industry. ‘Rentacrete’ if you will…

The Guardian Cities series has been discussing the idea this week in a feature on whether buildings should be demolished at the end of their lifetime. The feature largely looks at the ideas of Dutch architect and commentator Thomas Rau, the author of Material Matters. He talks about his ‘materials passport’ concept whereby all the materials in a building are logged with their properties to highlight their value when the structure is demolished. This is a refinement of the Building Information Modelling (BIM) system. Rau has put his passport premise into action for a couple of projects through his firm and the Madaster Foundation promotes its use.

The next steps that he envisages are buildings where the materials that constitute it are simply rented from the manufacturer. Since the material owners would now become companies they would have an interest in efficiency where the materials can be refitted, such as lighting, and/or recycled for when the building is torn down. In Rau’s view these companies would be in a better position to recoup the value of these materials when a building is demolished. He estimates that 18% of a building’s original construction cost can be preserved in this way. Suddenly, sustainability becomes much easier by changing one’s perspective on who owns what exactly in a building.

How this idea would work in practice raises all sorts of questions. For example, most buildings in the developed world last for as least as long as humans do. Which companies could be relied on to hang around this long? Building materials as a service might work for soft materials that are replaced more often, such as lighting and other interior fittings, but could this extend to a structure’s shell? One answer to this is that people invest in pension schemes and use banks quite happily over long periods time, so why not a building’s very fabric? Another issue is of liability and whether a manufacturer would want to take on additional responsibilities for its products decades later. This, and the idea in general, have similarities to the extended product responsibility strategy. Obviously someone needs to try out building materials as a service for real to tackle these questions and many more.

Building materials as a service is compelling but one reason that the construction industry has proved resistant to the digital revolution across the entire business, so far, is because it ultimately deals with physical products that people need permanently. Consumer digital renting services for media, like Netflix and Spotify, are ‘disposable’. Hence, the mindset is different. That’s not to say that building materials as a service is impossible just that it is a harder shift in thinking. A country with a high level of residential renting, for example, might find it easier to move to this model than one with high levels of home ownership.

One more thing to consider is that the media renting companies mentioned above are dependent on other companies producing the content. Due to this they have moved towards vertical integration as the producers themselves, notably Disney in 2019 which has started to set up its own online rental platform. The point here being that in a product rental environment, whoever produces the product, holds a large amount of influence. Building materials manufacturers take note. Building materials as a service might just be a talking point on the lecture circuit along the road towards sustainability in the construction industry. Yet if it did happen at any scale then the producers of concrete, mortar, bricks, steel and all the rest would be well placed to benefit from it.

China: Three cement plants in Dali, Yunnan province with a combined capacity of 5.0Mt/yr and belonging to Dali Cement (Group), Dali Hongshan Yunnan Cement and Hongta Dianxi Cement have ceased all functions except the packaging of existing cement in order to stop polluting the area of Erhai Lake. The shutdown was mandated by the City of Dali and Dali Economic Development Zone authorities in mid-2017. Xinhua Net newspaper has reported that the removal of kilns is underway and that demolition on all three sites will have been completed by 31 May 2020. The companies will be permitted to construct plants of corresponding capacities at allotted sites elsewhere.

Iceland: Iceland Cement has started demolishing its cement plant at Akranes. The 9 hectare site in the town will be used for housing and other projects, according to the Iceland Review magazine. FLSmidth originally built the plant and it was in operation since 1958 before it stopping manufacturing cement in 2012 when the company switched to imports from Norcem. Germany’s HeidelbergCement is the majority owner of the company.

Plans for the former Shoreham cement plant on the south coast of England took an exciting turn towards the end of 2014. Zero carbon design firm Zedfactory announced its plans to regenerate the brownfield site into an eco-resort featuring holiday homes, performance space, affordable homes, a hotel and conference centre, a watersports venue, wildlife preserves and more. Or, ' hobbit homes' as the Daily Mail put it when it covered the story six months later.

This raises the question of what happens to cement plants when they close?

In the UK, where a housing shortage in certain areas collide with NIMBY (not in my back yard) attitudes and strict planning regulations, former industrial or brownfield sites are prime sites for new housing developments. Subsequently, old cement plants are attractive to builders to build houses. Two examples of current sites heading this way include the former Cemex plant in Barrington, Cambridgeshire and the former Lafarge Eastgate plant in County Durham. Both sites have gained planning permission and were still in the pre-building stage according to local press reports in mid-2015. Dylan Moore's website 'Cement Plants and Kilns in Britain and Ireland' provides a good resource on former plants in the UK and Ireland.

One of the jokes about classic UK science-fiction television series Dr Who was that during the 1970s it was either filmed on cheap studio sets or in quarries. Endless encounters with alien beings took place in cement plant quarries including Lafarge Northfleet (alien in spacesuits), Lafarge Aberthaw (tentacle faced aliens), Hanson Ketton (Arthurian knights who may in fact be aliens...) and many more. Indeed, one of the conditions of the proposed Lafarge Eastgate sale in March 2015 was that a television production company could continue to use the quarry to film an adaptation of Beowulf for five years!

On the more imaginative side of what to do with old plants, La Fabrica near Barcelona is a spectacular example. Architect Ricardo Bofill converted a 19th century plant into his firm's head office, La Fabrica, and his own personal residence. As Ricardo Bofill Taller de Arquitectura's website puts it, "Eight silos remained, which became offices, a models laboratory, archives, a library, a projections room and a gigantic space known as 'The Cathedral', used for exhibitions, concerts and a whole range of cultural functions linked to the professional activities of the architect." Architecturally the project refers to Catalan Civic Gothic style with surrealist elements.

This sense of entertainment from industrial architecture was continued by sculptor Bob Cassilly in St Louis, USA who decided to build Cementland. Cassilly purchased the former plant and slowly assembled his clinker-themed version of Disneyland. Unfortunately he died in 2001 following an accident with a bulldozer at the site before he finished.

More and more former cement plants will be seeking new purposes as Europe rationalises its cement industries and excess capacity is eliminated. China too faces similar issues as it consolidates its industry. Most will probably lie fallow before eventually being knocked down and then turned into something following the cheapest economic path forward. With luck though, some will follow the dreams of Zedfactory and people like Ricardo Bofill and Bob Cassilly.

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China: The demolition of 17 more cement plants in Shijiazhuang, Hebei province, began on 17 February 2014, two months after the first batch of demolitions to improve air quality.

"After the second batch of demolitions is finished in March 2014, we can meet the target of reducing excess capacity three years ahead of schedule, reducing production capacity by 40%," said Wang Liang, the mayor of Shijiazhuang. Hebei was hit by many smoggy days in February 2014, causing serious pollution. On 17 February 2014 the air quality index exceeded 200, classed as 'very unhealthy' by the US Environmental Protection Agency (EPA).

The demolition of 18 cement grinders and 377 storage bins at the 17 plants will be completed by the end of March 2014, reducing production capacity by 9.1Mt/yr.

To control pollution, the provincial government has announced goals for cutting excess capacity in high-polluting industries, including cement production, in every city. Shijiazhuang, the provincial capital, must dismantle 15Mt/yr of cement production capacity by 2017.

The two batches of demolitions have targeted 35 plants, resulting in direct economic losses of US$180m and affecting 3780 workers. "We may suffer slow economic growth in the short term, but this will work in upgrading the economic structure and will result in a good living environment for our people, so it is worthwhile," said Sun Ruibin, Party chief of Shijiazhuang.

Wang Jiangtao, marketing manager at Yuancheng Construction Material Co, one of plants being demolished in the city of Luquan, said, "We will follow the government project and want to control air pollution as well so we agreed to close the plant. But it's still sad to see the plants being demolished," he said, adding that the company had invested more than US$4.94m in a new system in 2011. "We have not made enough money to cover the expenses up to now." Under government compensation plans, the plant may get US$1.65m and will receive other support for its future business, including preferential policies and tax relief, Wang added.

Two of Jinyu Dingxing Cement Co's plants were among the first batch of demolitions in December 2013, but so far new projects have not been decided on, said Feng Jinmin, a manager at one of the two plants that were closed. "Of the US$2.47m in compensation expected from the government, we have received half and are still awaiting government guidance on our future business," he said, adding that this may take years.

China: Shijiazhuang, Hebei province has started the demolition of its first batch of 18 cement plants on 17 December 2013 to fight air pollution. 74 cement plants in the suburbs of Shijiazhuang are targeted for deconstruction by March 2014 according to China Daily. The planned demolition is planned to include all the western areas of the city by 2017.

"The cement companies have been a major source of dust pollution, making them a priority for demolition," said Niu Yongzhi, the official from the Bureau of Industry and Information in Shijiazhuang who is in charge of the project.

Demolition of the first 18 cement plants will be completed in January 2014. Removal of these cement units is expected to significantly reduce dust and nitrogen oxides emissions. More than 3500 cement plant employees will lose their jobs in the demolition.

The government will pay compensation to the companies whose plants are being shut down. Seven plants in Pingshan county will receive an average of US$1.5m each and tax breaks will be given to the companies when they start other businesses. The other 11 cement plants in Luquan will receive similar compensation.

The 18 cement plants, scattered throughout the northwestern area of Shijiazhuang produce 9.4Mt/yr or about 21% of the city's annual output. By 2014 cement production capacity in Hebei will drop to 61Mt/yr, half of the province's cement production in 2012.