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Displaying items by tag: concrete
Treated slag makes the strongest concrete
09 April 2020Australia: A paper published in the journal Resources, Conservation and Recycling has reported that concrete made with treated slag is 8% stronger than standard slag concrete and 17% stronger than concrete made with conventional aggregates. A Royal Melbourne Institute of Technology (RMIT) team produced treated slag concrete using slag that had absorbed phosphate, magnesium, iron, calcium, silica and aluminium during use in wastewater treatment. Researcher Biplob Pramanik said, “The things that we want to remove from water are actually beneficial to concrete.” Pramanik said that the findings have promising implications for the water and concrete sectors within the circular economy.
Italy: Italcementi’s integrated Calusco plant near Bergamo has been awarded a Responsible Sourcing Scheme (RSS) certificate for its concrete and related supply chain operations. The certification looks at the entire production process from transportation to recycling raw materials. It is the first cement plant in the Italian subsidiary of HeidelbergCement to obtain the certification.
Italcementi suspended operation at its plants in March 2020 due to the coronavirus outbreak due to government decree.
A short look at low carbon cement and concrete
01 April 2020Cement 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.
Material | Type | Method | Product examples |
Cement | SCM cement | Lower clinker factor | Many products |
Cement | Limestone calcined clay cement | Lower clinker factor | LC3, FutureCem, Polysius activated clay, H-EVA |
Cement | Calcium silicate cement | Reduced process emissions | Solidia, Celitement |
Cement | Recycled concrete fines | Reduced lifecycle emissions | Susteno |
Cement | Geopolymer cement | Reduced process emissions | Vertua |
Cement | Calcium sulphoaluminate cements | Reduced process emissions | Many products |
Concrete | CO2 curing/mineralisation | Uses CO2 and reduces water usage | Solidia, CarbonCure Technologies |
Concrete | Recycled concrete coarse | Reduced lifecycle emissions | Evopact, EcoCrete, FastCarb |
Concrete | SCM concrete | Uses less or no cement | Cemfree, Carbicrete, Regen |
Concrete | Uses less cement in mix | Uses less cement | |
Concrete | Admixtures | Uses less cement | |
Concrete | Locally sourced aggregate / better supply chain logistics | Reduced transport emissions | |
Concrete | Geopolymer concrete | Uses no cement | E-Crete |
Concrete | Graphene concrete | Uses less cement | Concrene |
Concrete | Carbon offsetting | Separate offsetting scheme | Vertua |
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.
Germany: Schwenk Zement’s 1.2Mt/yr Karlstadt cement plant in Bavaria, 1.0Mt/yr Allmendingen and Mergelstetten cement plants in Baden Württemberg and 0.86Mt/yr Bernburg cement plant in Saxony-Anhalt have all achieved the Concrete Sustainability Council (CSC)’s gold certification, enabling the use of their cements in concrete for CSC certified sustainable buildings. Schwenk building consultancy head Werner Rothenbacher said, “Schwenk is committed to sustainable cement production at all locations. More works will follow soon.” In addition to its cement plants, Schwenk operates numerous ready-mix concrete production facilities in Germany.
In 2019 20% of German new-builds were CSC certified.
El Salvador: Switzerland-based LafargeHolcim subsidiary Holcim El Salvador has announced a planned investment of US$7.5m to establish six concrete plants in 2020, which will bring its total to 18 plants. Esmerk Latin American News has reported that the investment also covers ‘new trucks and other machinery.’ Holcim El Salvador also announced its intention ‘in the long term’ to resume operations at its 1.6Mt/yr Maya cement plant, mothballed in 2008, at an estimated cost of US$20m. It is currently investigating the possibility of installing a US$5m solar power plant at its 1.7Mt/yr El Ronco cement plant.
In 2019 Holcim El Salvador produced 1.2Mt of cement and 710,000m3 of concrete.
Oldcastle APG buys US MIX and US SPEC
04 March 2020US: Oldcastle APG, a subsidiary of CRH, has acquired dry mix manufacturer US MIX. The purchase adds to APG's dry mix manufacturing footprint and expands its network of facilities to the Denver, Colorado market. In addition, the acquisition provides APG with materials science expertise and adds another brand, US SPEC, to its existing dry mix product portfolio of Sakrete and Amerimix. No value for the acquisition has been disclosed.
US MIX primarily operates out of a manufacturing facility in Denver, with a secondary specialty bagging location in Fontana, California. Founded in 1968, US MIX has been privately owned by the Peterson family for over 50 years. Its products include bagged concretes, mortars and specialty cement mixes, in addition to liquid repair products.
US MIX currently operates as a Sakrete and Amerimix licensee and offers a variety of specialty products under the well-known US SPEC brand. US SPEC products are professionally engineered concrete and masonry repair products used in a variety of applications, formulated and tested in laboratory conditions under ASTM testing methods and specifications.
Boral fined US$9800 for slurry spill
02 March 2020Australia: The New South Wales Environment Protection Authority (EPA) has issued a US$9800 fine and a clean-up order to Boral for damage caused by a discharge of slurry from its Maclean concrete plant. The Daily Examiner newspaper has reported that a member of the public alerted the body to the spill, which issued from a storm drain into the Clarence River, on 15 October 2019. EPA north regulatory operations director Karen Marler said that the slurry ‘appeared to have been discharging from the Boral plant for some time prior.’ She said, “Subsequent EPA inspections confirm the clean-up and actions taken to improve plant operation were effective.”
UK: Germany-based HeidelbergCement’s subsidiary Hanson Cement will be the subject of a study in the use of biomass and hydrogen fuels coordinated by the Mineral Products Association (MPA). The Department for Business, Energy and Industrial Strategy is funding the Euro3.81m study, the results of which it says will be shared across the cement industry. HeidelbergCement CEO Dominik von Achten said, "In addition to our activities in the field of carbon capture, use and storage (CCUS), this project is an important step towards realising our vision of carbon-neutral concrete by 2050.”
Market in Turkey drags on Vicat’s sales in 2019
14 February 2020France: Vicat’s sales were reduced in 2019 by poor markets in Turkey and, to a lesser extent, Switzerland and Egypt. Its sales fell by 1% year-on-year to Euro2.74bn in 2019 from Euro2.58bn at constant scope and exchange rates. Its cement sales volumes dropped by 2% to 22.4Mt from 22.8Mt but its concrete volumes grew by 1.1% to 9.1Mm3 from 9.0Mm3. Its earnings before interest, taxation, depreciation and amortisation (EBITDA) decreased slightly to Euro156m.
“Strong growth in France, the US, Africa and Kazakhstan helped offset difficult market conditions in Turkey and Egypt. Furthermore, in line with our strategy of targeted acquisitions, the purchase of Ciplan in Brazil, in January 2019, allowed the group to continue its international growth in a region offering strong potential by integrating teams and assets of the highest quality,” said chairman and chief executive officer (CEO) Guy Sidos.
The group performed well in France, the US and Italy, especially due to the acquisition of Ciplan in Brazil. Sales in Turkey suffered from a generally poor economic situation. Competition in Egypt and a downturn in the precast concrete market in Switzerland caused problems in these countries respectively.
Cementos Pacasmayo sales boosted by infrastructure work in 2019
13 February 2020Peru: Cementos Pacasmayo’s sales have been boosted by infrastructure work, coastal El Niño reconstruction projects and private projects. Its cement, concrete and precast shipments rose by 10.6% year-on-year to 2.62Mt in 2019 from 2.34Mt in 2018. Its sales grew by 10.3% to US$410m from US$372m. Its consolidated earnings before interest, taxation, depreciation and amortisation (EBITDA) increased by 7.7% to US$118m from U$109m.