Displaying items by tag: geopolymer cement

Australia: Alternative cement and concrete producers have welcomed a new Australian civil engineering standard that allows builders to use reduced-CO₂ geopolymer concrete in infrastructure projects. Wagners, which produces Earth Friendly Concrete (EFC), said that the revision has removed on if its key barriers to wider market acceptance. EFC replaces 100% of cement with supplementary cementitious materials, including ground granulated blast furnace slag (GGBFS) and pulverised fly ash, by virtue of its binder technology. Wagners previously supplied EFC for the London Power Tunnels project in the UK, based on local technical approval-based building codes. The producer now expects a new standard like the Australian one to follow in the EU.

US: SLB has launched EcoShield, a geopolymer-based well cement product. The company, also known as Schlumberger, says that the product cuts out up to 85% of embodied CO₂ emissions compared with conventional well cementing systems because it does not use ordinary Portland cement (OPC). It also reduces transport related emissions by using locally-sourced natural materials and industrial waste streams in its composition. The company says that the cement-free system can be deployed throughout various phases of the well life cycle, including abandonment. It can also be deployed across a range of field applications, including corrosive environments.

Jesus Lamas, SLB’s president of Well Construction, said “Decarbonising the well construction process while ensuring safety and performance standards is critical to our industry’s pathway to net zero.” He added “The cement-free EcoShield system is a breakthrough that delivers industry-standard zonal isolation capabilities while significantly minimising impacts from upstream oil and gas production.”

EcoShield has been tested by Pioneer Natural Resources in the Permian Basin on an 18-well field testing campaign and its use is ongoing.

UK: Karbonite UK has developed a new supplementary cementitious material consisting of mineral feedstock, geopolymers and waste biomass. The process also involves CO₂ sequestration and liquid-infused CO₂ absorption within the mineral structure. The material, called Karbonite, is activated at 750 – 850°C, releasing water, which is captured for recycling. Its CO2 emissions are 2.7kg/t, according to Karbonite UK. The developer says that Karbonite ground with 50% clinker yields a cement of equal compressive strength to ordinary Portland cement (OPC).

Karbonite UK is currently preparing a final report on the product for a major cement producer.

Managing director Rajeev Sood said “Karbonite offers a wealth of potential to an industry targeting net zero. We are excited to talk to cement and concrete producers about how they could integrate Karbonite technology into their existing process.”

World: Market Research Future has forecast a 15% composite annual growth rate (CAGR) in global green cement demand between 2018 and 2023, where green cement is defined as fly ash cement, slag cement, geopolymer cement and other cements produced using alternative raw materials. Market Research Future predicts that fly ash cement’s global growth will be the sharpest due to its abundant availability. Its report concluded that cement sector strategies in response to the growth would include mergers, joint ventures and acquisitions.

Mexico: Cemex plans to launch its net-zero CO₂ Vertua concrete product worldwide following its release in Europe. It said that customers in several European countries are using Vertua in infrastructure projects and climate-friendly building projects.
“We believe that climate change is one of the biggest challenges of our time, and we are committed to doing our part to address it. Vertua is clear evidence that we can transition to a carbon-neutral economy, where concrete is an essential component in the development of climate-friendly urban projects, sustainable buildings, and resilient infrastructure,” said Fernando A Gonzalez, chief executive officer (CEO) of Cemex.

Vertua uses a geopolymer binder solution created by Cemex’s Research and Development Center in Switzerland. This solution has a reduced carbon footprint of up to 70%, The compensation of the remaining CO₂ is achieved by participating in reforestation projects, among other initiatives.

Mexico: Cement has announced the launch of a range of carbon neutral concretes called Vertua. By offsetting, Cemex has eliminated Vertua’s remaining carbon footprint following a 70% reduction in embodied emissions compared to Ordinary Portland Cement (OPC) through use of a geopolymer cement mixture. The concretes will become available on different markets globally in 2020 and 2021.

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.