Displaying items by tag: concrete

UK: SigmaRoc subsidiary CCP has launched Greenbloc Standard, Ultra and Premium. The new designations correspond to 50%, 80% and 100% cement substitution. Professional Builder News has reported that Using Greenbloc Standard reduces structures’ CO₂ emissions by 77% compared with structures built with conventional ordinary Portland cement (OPC)-based blocks. For an average semi-detached house, this is equivalent to 2.7t of CO₂.

CCP general manager Phil Rotheram said “The expansion of our Greenbloc range continues our commitment to sustainable alternatives to our product offering as we fully commit to the challenges of removing embodied carbon from the built environment.”

Greenbloc Ultra featured in a gold medal-winning garden at the RHS Chelsea Flower Show 2023 in May 2023.

France: Cemex France and Ecocem have signed a deal to collaborate on the development of reduced-CO₂ concrete development at 10 Cemex France ready-mix concrete batching plants. The partnership will explore methods that include the use of supplementary cementitious materials in place of clinker. Cemex hopes that the collaboration will help to realise its goal of a 55% CO₂ emissions reduction across its European operations by 2030.

Cemex Western Europe vice president materials and Cemex France president Michel Andre said “Cemex continues to reinforce its commitment to advancing the sustainability agenda with the announcement of this extended partnership with Ecocem. We know that if we are to achieve our global ambition of operating as a net-zero business by 2050 we must prioritise exploring innovation and new technologies with like-minded companies who share our dedication to leading the industry’s transition to a lower carbon and circular economy.”

Betolar has called today for a global performance-based standard to replace existing prescriptive standards. Riku Kytömäki, the head of Betolar, argued at the London-based Concrete Expo that the lack of a performance-based standard is holding back the use of low-carbon materials from replacing cement in concrete production. He said “the current regulations across the markets are restricting the use of circular materials allowed in concrete buildings.” Betolar produces Geoprime, an additive designed for use in cement-free concrete production with ash and ground granulated blast furnace slag (GGBFS). This gives the company a financial reason to want standards to change, as it will potentially allow it to sell more of its product. However, as the company points out, “there is a huge need for new alternatives.” The world needs around 4Bnt/yr of cement but there is only 300Mt/yr of slag available.

Building materials producers and related companies wanting to change rules and standards in response to new trends is a common refrain. For instance, the increased use of alternative fuels by the cement sector has prompted all sorts of regulatory changes. However, rather than simply asking for amendments to the existing ways of doing things, Betolar is advocating for more wholesale change. It isn’t alone. Also this week the ASTM in the US announced that it is writing a specification to include a wider range of secondary cementitious materials (SCM). In addition, many of the interviews Global Cement Magazine has conducted with companies developing and marketing new types of cement and concrete in recent years have said similar things. Examples include the use of graphene, carbon nanotubes or sequestering CO₂ into industrial by-products to create novel secondary cementitious materials (SCM).

Prescriptive versus performance-based approaches to buildings and building materials tie into wider design philosophies about construction. The prescriptive approach provides detailed descriptions of regulations, methods and components, such as cement and concrete standards. With respect to concrete standards, this might mean setting mandatory SCM and cement proportions, determining allowable water content, certain types of aggregate to be used and so on. The performance approach focuses on the end results, although it can be just as codified and standardised as the prescriptive route. For concrete, for example, this means that performance is measured by standard test methods with defined acceptance criteria stated in the contract documents with no restrictions on the parameters of concrete mixture proportions.

For cement and concrete standards the prescriptive approach dominated in Europe and North America in the 20th century. However, this began to change in the US in 2002 when the National Ready Mixed Concrete Association (NRMCA) started working on its roadmap towards its Prescription to Performance (P2P) initiative. The key aim of the scheme was to shift the emphasis from prescribing (or indeed proscribing) the ingredients and their proportions in a concrete mixture to an emphasis on the performance properties of the combined materials. A decade later in the mid-2010s it found during a progress review that about half of the sample of project specifications studied were classified as ‘prescriptive.’ The biggest prescriptive restriction was on the quantity of SCMs set by specification writers. These were often percentages required in certain circumstances, such as freezing and thawing cycles, but imposed on all usage.

The current bout of interest in performance-based standards appears to be driven by the growing demand for cement and concrete products to lower their clinker factor by using higher amounts of SCMs. A far wider range of SCM-based products are being developed and coming to market and then encountering regulatory burden. These new material manufacturers are meeting up with the sustainability lobby, which also has an interest in decarbonising building materials. In 2022, for example, the Belgium-based Environmental Coalition on Standards (ECOS) started pushing for performance-based standards for cement. In a statement it said that, “it is commonly accepted that prescriptive specifications are convenient, but that this convenience is obtained at the expense of (eco-) innovation and decarbonisation.” It added that the switch to performance-based standards would also strengthen the European internal market for construction products as part of the Construction Products Regulation (CPR). It noted the ASTM standards for hydraulic cements (ASTM C-1157), that were developed in the 1990s in the US, and more recent developments in the field in Latin America.

It is worth pointing out that the prescriptive route does have its advantages. Using a prescriptive system is easier for less-experienced practitioners or generalists as it sets a minimum standard, even if it is over-engineered. Responsibility is shared out among the supply chain under a performance-based system for the quality of concrete. Under a prescriptive system, the supplier or contractor can be held responsible for quality control issues. For the performance approach this has to be specifically defined, although systems are in place to help. Making it harder via ‘red tape’ for new products to enter a market may stifle innovation but it also gives these new products far more time to be tested rigorously.

The whole prescriptive-performance standards issue opens up the wider implications of decarbonising construction materials. Where once there was a relatively small number of different types of cement and concrete now there are potentially hundreds, each looking for market share. Whether this situation will be the same in a decade’s time remains to be seen. A few common SCM-based cement and concrete products and formulations may predominate. For now, the future seems wide open and bigger changes, such as the global performance-based standards Betolar is advocating, may be required to support this. Considering the massive variation between countries and states, even within the US and the European Union, let alone the rest of the world, this seems ambitious. But it is not impossible!

UK: Riku Kytömäki, the chief executive officer of Betolar, has called for a global performance-based standard to replace the current building requirements that restrict the use of new low-carbon materials to replace cement in concrete production. He made the comments at the London Concrete Expo. Kytömäki argued that current standards state that concrete manufacturers must use a certain percentage of cement to strengthen the finished product. Betolar’s product Geoprime is an additive designed for use in cement-free concrete production with ash and ground granulated blast furnace slag (GGBFS). However, “ageing” standards rule out the use of these kinds of products such as this despite their sustainability advantages.

Kytömäki said “It is time for global concrete industry to step up their sustainability efforts. New material innovation is available. It is cost-effective and helps to meet stricter durability requirements. However, the current regulations across the markets are restricting the use of circular materials allowed in concrete buildings.” He added that his company’s product Geoprime, “does not require large investments, but there is regulation to be developed quickly so that new solutions and materials can be used."

Betolar says it has analysed over 200 side-streams other than slag and fly ash, providing flexibility to process locally available side-streams. It added that there are also significant CO₂ savings to be found in logistics when manufacturing processes take place near the source of the industrial side-streams.

India: More than 75 representatives from academic institutions and businesses from across the world are attending the Innovandi Global Cement and Concrete Research Network (GCCRN) Spring Week taking place in New Delhi. The GCCRN has brought together 450 researchers and scientists from more than 40 universities and institutions, including the EPFL in Switzerland, South East University in China, University of Toronto in Canada, the Indian Institute of Technology Delhi, the University of Cape Town, Imperial College London in the UK, as well as 35 cement and concrete manufacturers and their suppliers. The focus of the conference is to work towards reaching net-zero CO₂ concrete production, including sourcing and improving alternatives to clinker, work on calcined clays, concrete recycling – plus its carbonation and durability - as well as kiln electrification and carbon capture, usage and storage (CCUS).

Claude Loréa, the Innovation and ESG Director at the Global Cement and Concrete Association (GCCA), said “Global Innovation collaboration and research will help unlock our industry’s decarbonisation mission. Spring Week is the key date in the GCCA’s Innovandi calendar. It provides an opportunity for our partners to meet face-to-face, exchange ideas, run workshops, and measure progress on key research projects in line with our industry’s 2050 Net Zero Roadmap. Our industry and our key partners are stepping up to the challenge and it’s fantastic to see the progress on some of the 75 PhD candidates supported by the GCCRN.”

The event is also updating attendees about progress made by projects involved with the Innovandi Open Challenge. This initiative matches start-ups with GCCA member companies from around the world, to help scale up research and technical innovation. Two of the six start-ups selected in 2022 at the first ever Innovandi Open Challenge, which focused mainly on carbon capture and utilisation, have already gone to pilot stage. Applications for the second challenge, which focuses on low carbon concrete, close on 15 May 2023.

The GCCRN was set up by the GCCA, a lobbying group representing more than 80% of the world’s cement and concrete manufacturers outside of China. All GCCA member companies are committed to decarbonising the industry by the mid-21st Century, in line with the GCCA’s Concrete Future 2050 Net Zero Roadmap.

Heidelberg Materials announced a US acquisition at the same time as the ongoing IEEE/IAS-PCA Cement Conference in Dallas, Texas this week. It has entered into a purchase agreement to acquire The SEFA Group, a fly ash recycling company based in Lexington, South Carolina. Its operations include five beneficiation plants, five utility partners, 20 locations and over 500 employees. It supplies fly ash to over 800 ready-mixed concrete plants in 13 states. It processes around 1Mt/yr of ash from storage ponds using its proprietary thermal beneficiation process. No value for the acquisition was disclosed.

The proposition for a heavy building materials manufacturer of securing a supply of fly ash is an attractive one. Fly ash can improve the performance of concrete, reduce its cost by lowering the amount of ordinary Portland cement (OPC) required and decrease the associated carbon footprint. It can also be use to make blended cement products. Heidelberg Materials and its US-subsidiary Lehigh Hanson could have various options here including using this new supply of fly ash internally, selling it on to other companies or licensing the beneficiation technology. Heidelberg Materials’ global sustainability report in 2021 reported that just under 9% of its cement-type portfolio comprised pozzolana or fly ash cements.

Graph 1: Coal combustion product production and use, 1991 – 2021. Source: ACAA.

Data from the American Coal Ash Association (ACAA) shows in Graph 1 that coal combustion products (CCP) production have declined in the last decade as the proportion used has steadily risen. In its annual production and use survey, the ACAA revealed that the use of harvested ash continued to grow in 2021 and that it constituted around 10% of the volume of ash recycled from current power plant operation. Thomas H Adams, the executive director of the ACAA, said “The rapidly increasing utilisation of harvested CCP shows that beneficial use markets are adapting to the decline in coal-fuelled electricity generation in the US. New logistics and technology strategies are being deployed to ensure these valuable resources remain available for safe and productive use.” Separately, the ACAA reported that coal-fuelled power stations represented about 50% of the country’s electricity demand in the mid-2010s compared to 20 – 25% in 2021 despite base-load remaining the same. It forecast that fly ash production was likely to remain fairly constant to around 2040 but that harvesting would help to cut the gap between supply and demand in some regional markets. It said that over 2Bnt of coal ash was in disposal. However, no indication of how recoverable this was given although it did note the higher cost of beneficiation. Work on updating specifications was ongoing to suit current circumstances.

As with the slag market, this presents a dilemma for cement and concrete producers that want to become more sustainable. They want to use more by-products from other carbon-intensive heavy industries – such as coal-fired power stations and steel plants – but these industries themselves are also trying to become more sustainable and are producing less secondary cementitious materials. Heidelberg Materials’ interest in a fly ash beneficiation company makes sense because it secures a bigger portion of a dwindling resource from the direct operations and opens up the possibility of selling the beneficiation technology to others. It is also worth mentioning that other fly ash thermal beneficiation processes are available. For example, Charah Solutions installed its MP618 technology at its Sulphur terminal in Louisiana in early 2019.

The general fly ash market in the US looks set to track the level of coal-fired power generation for the foreseeable future. Yet the proportion of CCPs being used continues to rise. In this context focusing on harvesting may be starting to make more financial sense. Charah Solutions’s new unit in 2019 and SEFA Group’s new units in 2020 and 2021 seem to support this view. Heidelberg Materials’ acquisition of SEFA Group may be further confirmation of this.

Mexico: The construction materials producer GCC reported double-digit growth in its first quarter results, driven by higher prices for its products in Mexico and the US. Its operating earnings before interest, tax, depreciation and amortisation (EBITDA) for the first three months of 2023 rose by 16% year-on-year compared to the same period in 2022 to reach US$63m, while revenues rose by 18% to US$243.9m.

"GCC delivered solid results in the first quarter," said Enrique Escalante, GCC’s chief executive officer. "High demand continues and we are leveraging all of GCC's resources to ensure we deliver the highest profits and strengthen our margins."

The growth in revenue was driven by higher ready-mixed concrete (RMC) sales volumes in the US, which were 27% higher than in 2022, and 11% higher cement and RMC volumes in Mexico. GCC also noted an increase in cement and RMC prices of 21% and 6%, respectively, in the US, while in Mexico the increases were 13% for cement and 11% for ready-mix.

Holcim launched its formal take on construction and demolition waste (CDW) this week with the unveiling of its ECOCycle technology platform at the BAU architecture fair in Munich. This amounts to managing the distribution, processing, grinding and recycling of CDW back into new building material products. It claims that its concrete, cement and aggregate products can contain 10 - 100% of CDW with no drop in performance.

It is hard to gauge whether this is marketing for existing operations or the start of something new. Yet, in its 2022 Sustainability Report, Holcim said that it recycled 6.8Mt of CDW back into building products and that it is on track to meet its target of 10Mt by 2025. This target was neatly put into words as wanting “to build more new buildings from old ones.” Ahead of the announcement of the launch of ECOCycle, it added that it was going to roll out its Susteno product around Europe. This product, made from 20% CDW, was originally released in Switzerland in the late 2010s. Notably, recent acquisitions by Holcim that connect to its growing focus on CDW include Poland-based Ol-Trans in July 2022, UK-based Wiltshire Heavy Building Materials in October 2022 and UK-based Sivyer Logistics in April 2023.

As covered by Global Cement Weekly in February 2023, Holcim is not the only heavy building materials company pivoting to CDW. The European Union (EU) set a 70% recovery target for it in 2020 and various cement company sustainability reports have described the region as being receptive to moves into this sector. Cemex set up a global waste management subsidiary called Regenera at the end of January 2023. This division covers both alternative fuels, CDW and industrial by-products, so it is more general than Holcim’s current effort, but it shows intent in the same direction. Cemex previously set a target of recycling 14Mt/yr CDW by 2030.

Heidelberg Materials has been working on developing recycled concrete paste and its ReConcrete-360° concrete recycling process. As of its last sustainability report, this process had been tested at the pilot scale and is now being developed and scaled for industrial application. In addition to acquiring UK-based Mick George Group in December 2022 Heidelberg Materials has also purchased Germany-based RWG Holding in January 2023 and Germany-based SER Group in February 2023. All three companies operate in the CDW sector.

The other notable contribution that Heidelberg Materials has been making is as a partner of the ‘Circular City - Building Material Registry for the City of Heidelberg’ project. When Heidelberg Materials announced its involvement in the initiative in mid-2022 it said it was the first city in Europe to apply the principles of urban mining. The goal of the project is to take an inventory of the city’s buildings and then compile it in a digital material registry. The basis for the registry is the Urban Mining Screener developed by EPEA (Environmental Protection Encouragement Agency). This programme can estimate the composition of buildings based on building data such as location, year of construction, building volume or building type. Circular economy supply chains can then act accordingly when a building is retrofitted, demolished or deconstructed. So, for example, at the start of the project it worked out that a former US Army housing estate conversion site was calculated to contain approximately 466,000t of material, with about half in the form of concrete, a fifth in the form of bricks and 5% as metal.

That last example compares to a European Commission estimate that, as a whole, Europe generates around 450 - 500Mt/yr of CDW. A third of this is concrete. As with alternative fuels and slag previously, this may be money going into the ground. Recycling building materials is not new but any significant increase in reusing CDW that can reduce the clinker factor of cement (and the cement factor of concrete) offers a potentially cheaper route to building materials decarbonisation than carbon capture and utilisation/storage at current costs. Hence the continued interest.

Switzerland: Holcim has launched ECOCycle, its initiative to recycle construction demolition materials into new building products. It says it can recycle construction demolition materials across a broad range of applications, from decarbonised raw materials in low-carbon cement formulation, to aggregates in concrete and fillers in road construction.

Jan Jenisch, the chief executive officer of Holcim, said “Across all metropolitan areas where we operate, we are at the forefront of driving circular construction to build new from the old. With our ECOCycle technology we can build cities from cities, recycling 100% of construction demolition materials into new solutions, so everything gets reused and nothing gets lost. With our world’s growing population and urbanisation, circular construction is essential to build a future that works for people and the planet.”

The building materials producer is deploying its ECOCycle technology across its range of products to scale up circular construction. It says that its process enables concrete, cement and aggregates to contain from 10 - 100% recycled construction and demolition waste with no change in performance. The initiative is supported by distributing, processing, grinding and recycling construction and demolition materials into new building material products.

ECOCycle brings together previous work Holcim has conducted in the field such as launching a cement in Switzerland made with 20% demolition and construction waste. The company is now launching this product elsewhere in Europe. In France it is building an affordable housing complex using 100% ECOCycle recycled concrete. In the UK it is building a residential area with 50% ECOCycle aggregates that have been made from 100% recycled construction demolition materials.

US: A team from the Massachusetts Institute of Technology (MIT) has developed a new method to sequester CO₂ in concrete before curing it. The method is based on the addition of bicarbonate of soda, which reacts with cement to produce a calcium carbonate-calcium silicone hydrate composite. The Journal of Engineering has reported that the method adds the benefits of CO₂ mineralisation during production and casting, doubling the mechanical performance of early-stage concrete. It also eliminates the effects of carbonation reactions in cured concrete, which weaken the concrete by lowering its alkalinity, which accelerates the corrosion of rebar. The method has the potential to sequester 15% of CO₂ emissions from cement production.

The team said “The pre-curing capacity of concrete to sequester CO₂ has been largely underestimated and underutilised. Our new discovery could further be combined with other recent innovations in the development of lower carbon footprint concrete admixtures to provide much greener, and even carbon-negative, construction materials.”