Displaying items by tag: CarbonCure

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.

US: Hawaii’s Department of Transportation plans to use carbon-injected concrete for its new projects. This will include a new structure to protect a highway tunnel from rockfalls, according to Reuters. The Department of Transportation was testing CO₂-injected concrete on an access road project with CarbonCure Technologies in May 2019. The latest decision follows a resolution by state legislators that city administrators ‘consider’ using CO₂-injected concrete in city and county infrastructure where concrete is used.

In late June 2019 CarbonCure announced that its had formed a partnership with HC&D Ready Mix, a local concrete producer, to use its CO₂-injected concrete process. It is the second deal with a concrete producer in the state that CarbonCure has arranged.

Canada: Sean Monkman, Senior Vice President of Technology Development at CarbonCure Technologies, has been named as Canada’s inaugural Mission Innovation Champion at the fourth annual Mission Innovation Summit (MI4) and 10th annual Clean Energy Ministerial (CEM10) summit hosted by Canada in Vancouver, British Colombia in late May 2019.

Mission Innovation, a global initiative involving 22 countries and the European Commission, has identified carbon capture utilisation and storage (CCUS) as one of eight Innovation Challenges that are key to achieving substantial emissions reductions. Mission Innovation Champions were selected from member countries to celebrate individuals with a track record of progressing creative new ideas that drive the pace and scale of the clean energy revolution.

US: CarbonCure Technologies has appointed Ted Jones as its Vice President of Sales and Marketing. Previously he worked as the sales and marketing lead with Oldcastle Precast, Contech Engineered Solutions, and The Fort Miller.

Jones succeeds Bill Holden as Vice President of Sales. He will be launching and spearheading a new Industry Advisory Council, which is an advisory board made up of concrete industry leaders. He will continue to sit on CarbonCure’s Board of Directors. Jennifer Wagner, the former Vice President of Marketing, has been promoted to the Executive Vice President of Corporate Development.

US: CarbonCure has demonstrated an integrated CO₂ capture and utilisation (CCU) process from cement for concrete production in January 2018 at Cementos Argos’ Roberta plant in Calera, Alabama. The consortium - comprising Carbon Cure, Sustainable Energy Solutions (SES), Praxair, Cementos Argos and Kline Consulting - says it is the world’s first project to collect cement kiln CO₂ for subsequent utilisation downstream in concrete production and construction.

CO₂ emissions from the Roberta cement plant were captured by SES’ Cryogenic CO₂ Capture technology, transported by Praxair and reused in Cementos Argos' Glenwood, Atlanta concrete operations equipped with CarbonCure's CO₂ utilisation technology. The concrete manufactured with the waste CO₂ from the Roberta cement plant was then used in a local construction project in the greater Atlanta area. Design partners and fellow members of CarbonCure’s Carbon XPRIZE team such as LS3P Architects, Uzun + Case Structural Engineering, and Walter P Moore Structural Engineers completed the end to end integrated solution by creating demand for CarbonCure concrete products in the marketplace. Kline Consulting oversaw the commissioning and reporting of the industrial demonstration.

The project was an extension of Team CarbonCure's participation in the US$20m NRG COSIA Carbon XPRIZE Challenge, which incentivises and accelerates the development of integrated CCU technologies and new markets that convert CO₂ emissions from coal and natural gas power generation into valuable products.

US: Cementos Argos has started incorporating and capturing recycled carbon dioxide (CO₂) in several of the concrete mixtures it produces at its US plants, specifically the ones in Atlanta, Georgia. The CO₂ is collected, stored and taken to the plant by the Canadian company CarbonCure, which developed the batching technology. The gas chemically reacts with the calcium hydroxide and the water of the concrete, making insoluble calcium carbonate.

“We are extremely proud of being the first company in the United States to be able to offer its customers a product with CO₂-capturing and incorporating properties. This concrete, even when demolished, never releases the CO₂ contained within its structure, allowing us to close the gas’ cycle and contribute to making the construction sector more and more sustainable and eco-friendly,” said Jorge Mario Velásquez, CEO of Cementos Argos.