Displaying items by tag: ground granulated blast furnace slag

UK: Tarmac has demonstrated a new concrete product using a high proportion of slag with Align, the joint venture building part of HS2, a new high-speed railway line. It demonstrated the potential to use very high ground granulated blast furnace slag (GGBS) content in excess of 90%, as an alkali activated cementitious material conforming to BS EN197, the standard for cementitious materials allowed to be used in ready mixed concrete, to significantly reduce carbon emissions, whilst still producing a quality finish and allowing normal construction and demoulding times.

Demonstration and testing at full scale used one of three Tarmac concrete batch plants at a Chalfont Lane construction site in Hertfordshire. A structural slab forming part of the new viaduct pre-cast factory and a vertical wall were poured. Tarmac says that the mixes, designed to Align concrete specification, exceeded expectations in both fresh and hardened properties, and showed that the new concrete can be produced in normal concrete plants and placed via mixer truck and by skip with a tremie pipe. The new low carbon concrete has a carbon footprint following industry BSI PAS2050 calculation rules that gives a 62% reduction in CO₂e per cubic metre of concrete, compared to a standard CEM I concrete, meeting the same specification in the same raw materials. The footprint covers all aspects of the concrete production and supply with no carbon off-setting applied, delivering an actual footprint of 133kg/m³ CO₂e. This represents a saving of 220t CO₂e for every 1000m³ produced.

“Together we’ve shown this new concrete is fit for purpose in slabs and walls, with good repeatability and works with standard production and construction methods. This product is a great step along the industry zero carbon routemap, and the demonstration will help accelerate adoption of this new concrete,” said Robert Gossling, head of commercial engineering solutions at Tarmac.

Tarmac is supplying concrete for the construction of the Central 1 section of HS2 Phase One that is being built by Align. This includes a 22km section of high-speed rail infrastructure incorporating a 3km viaduct across the Colne Valley, a 16km twin-bored tunnel, and five vent shafts handling both intervention and tunnel ventilation facilities.

South Korea: Continental New Materials has awarded a granulated blast furnace slag (GBFS) supply contract to steel producer POSCO. Continental New Materials applies technology developed at the Ulsan National Institute of Science Technology (UNIST) to produce clinker-free cement.

POSCO's hot rolled and wire rod marketing manager Kim Dae-Up said "We will continue to provide support so that POSCO's steel by-products can become eco-friendly cement materials and contribute further to carbon reduction."

US: The United States Geological Survey (USGS) estimates that the US sold 17Mt of ferrous slags in 2021, a rise of 31% year-on-year from the estimate in 2020. Blast furnace slag represented about 49% of the volume sold and accounted for 87% of the total value ofslag, most of which was granulated. Steel slag produced from oxygen and electric arc furnaces accounted forthe remainder of sales. Slag was processed by 28 companies servicing active iron and steel facilities or reprocessing old slag piles at about 124 processing plants, including some iron and steel plants with more than one slag-processing facility, in 33 States, including facilities that import and grind unground slag to sell as ground granulated blast furnace slag (GGBFS).

A further 2.2Mt was imported, a slight decline from 2020. From 2017 to 2020 the USGS reports that 42% of imported slag came from Japan, 18% from Brazil, 11% from China and 10% from Italy.

The USGS noted that during 2021, domestic GGBFS remained in limited supply because granulation cooling was known to be available at only two active US blast furnaces while, elsewhere, only one domestic plant produced pelletised slag in limited supply. Grinding of granulated blast furnace slag was only performed domestically by cement companies. However, following Covid-19 related decrease in availability in 2020, supply of steel slag increased in 2021.

UK: Ecocem and construction company Taylor Woodrow have conducted the first pour of the Exegy ultra-low CO₂ concrete at waste management site in London. The mix used on the project is reported to reduce the carbon footprint by up to 70% when compared to traditional concrete. Cemex also collaborated on the project by producing the concrete used for the pour.

The concrete product was developed by Ecocem and Vinci Construction, using Ecocem Ultra, as part of Vinci Construction’s ultra-low carbon concrete range. Ireland-based Ecocem is a producer of cement and additives made using ground granulated blast furnace slag (GGBFS). Exegy is already being used at a pilot site of the Grand Paris Express and in the construction of the Athletes’ Village in Paris for the 2024 Summer Olympic Games.

Micheál McKittrick, managing director, Northern Europe, Ecocem, said, “Our Ecocem Ultra technology is already being used at scale in France, and we’re excited to now see it being adopted in the UK.” He added, “The cement and construction industries are developing and deploying a range of emission reduction technologies to help the UK Government reduce emissions by 78% by 2035, and reach net zero by 2050, and Ecocem will add a further dimension to these efforts.”

UK: Tarmac has started a long-term slag stevedoring contract with Associated British Ports (ABP) at Port Talbot in Wales. The new arrangement at Port Talbot will see ABP load 300,000t/yr of ground granulated blast furnace slag (GGBFS). The slag will then typically be used in concrete production elsewhere in the UK. The agreement follows other partnerships between Tarmac and ABP at existing ports in Cardiff, Swansea, Newport, Garston (Liverpool), Southampton and Ipswich.

Andrew Harston, ABP Wales and Short Sea Ports director, said, “ABP continues to invest in its ports’ infrastructure and services, as well as sustainability measures, and we are delighted to win this new contract with Tarmac, which shares our commitments to the highest standards of health and safety, and sustainability.”

UK: Hanson has delivered its 10,000th load of Regen ground granulated blast furnace slag (GGBFS) from its Port Talbotsite in Neath Port Talbot to the building site of the upcoming Hinkley Point C power plant in Somerset. The GGBFS will be used in concrete production there. The latest batch brings the company’s total deliveries to the project to over 230,000t of GGBFS.

Head of nuclear operations Stewart Cameron said “Around 200,000t of CO₂ has been saved in reaching this milestone Regen GGBS load. It is a credit to all those involved as we continue to meet the standards expected of this high-profile project.”

Romania: Liberty Galați said in June 2021 that it exported 50,000t of granulated blast furnace slag (GBFS) to France. The steel company said that a French cement producer will use the GBFS along with clay and gypsum in clinker-free cement production. The alternative cement reduces CO₂ emissions by 80% compared to ordinary Portland cement (OPC), according to the supplier. Liberty Galați’s operations generate 500,000t/yr of GBFS. It says that it has cement industry customers across Europe and Africa.

General Director Aida Nechifor said “Our ambition to become carbon neutral by 2030 involves a new metallurgical route – using direct iron reduction and smelting in electric arc furnaces – increased scrap metal recycling and a transition to domestically-generated green energy. However, we are very happy to be able to ensure that even the by-products of our current production process, such as GBFS, can be used better to help reduce the carbon footprint of other products.”

UK: Hanson’s Regen Ground Granulated Blast furnace Slag (GGBS) product is being used by BAM Nuttall and Network Rail in the first and second phase of building a new sea wall in Dawlish, Devon. So far 4600m³ has been supplied to the project that is intended to protect a railway line from the sea. The bespoke mix being utilised for the project uses Regen GGBS to create a pumpable low carbon concrete that is strong enough to withstand erosion, waves and storm winds while reducing the amount of carbon generated by two-thirds.

“From the earliest phase of this project, we have considered how this scheme can limit its environmental impact without compromising the strength and resilience of the structure. The final design uses piles buried deep in the bedrock to create stability for the structure. Those piles are protected by prefabricated facing panels created off-site and reinforced by concrete poured in behind the visible section of wall,” said Jack Brookes, site agent for BAM Nuttall.

The project has also had to face difficult logistical, technical and operational challenges created by pouring large amounts of high specification concrete up to 200m through the night in very short tidal windows. Hanson plans to supply a further 4500m³ of concrete to the project.

UK: DB Group and Wolfenden Concrete have announced the upcoming launch of Supa Green, a range of cement-free agricultural concrete products produced using DB Group’s Cemfree technology. The partnership says that this assures a 62% maximum CO₂ reduction compared to concrete products made with Ordinary Portland Cement (OPC). It further says that the products have increased acid resistance. Cemfree is a low carbon concrete made using ground blast furnace slag (GGBS) and pulverised fly ash.

DB Group chief executive officer Wayne Zakers said, “DB Group’s mission is to improve the durability and sustainability of construction, working most intimately with our innovative partners. Working with Wolfenden will enable us to embed that innovation within the agricultural sector and to extend the benefits of our Cemfree technology to dairy farmers across the UK. The testing of Supa Green products has proven extremely successful, and so we look forward to the launch of the range, and to helping Wolfenden’s customers meet and exceed environmental targets.”

Canada: Carbicrete has secured US$1.5m in funding from US-based SQN Venture Partners (SQNVP). The funds will finance research and development activities at its new Lachine laboratory, as well as operations at its Drummondville pilot plant in Quebec. It said that this brings its total funding received from major investors in 2020 to US$8m with investment already agreed from Harsco Environmental, the Quebec Ministry of Energy and Natural Resources and Sustainable Development Technology Canada (SDTC). The technology company is developing concrete products made with steel slag for the construction industry.

Chief executive officer (CEO) Chris Stern said, “This venture debt cash injection following our equity financing further underlines the thesis that the financial markets are believing in value-added, carbon-negative technologies such as CarbiCrete that mitigate CO₂ in our atmosphere. We are proud to have SQNVP as an investor in our company.”