Displaying items by tag: recycled concrete paste

Cemex launched a new waste management division called Regenera this week. Cemex describes Regenera as a “business that provides circularity solutions, including reception, management, recycling, and coprocessing of waste.” The Mexico-based company has a long and leading history with sourcing and using alternative fuels in the cement sector and the new organisation looks set to utilise this experience. What is notable though is how the business is targeting three waste streams: municipal and industrial; industrial by-products; and construction, demolition and excavation waste (CDEW). Bringing the three waste streams together in this way appears to be novel for the heavy building materials sector, particularly the inclusion of CDEW, which we will explore further here.

CDEW is split into fractions, just like the municipal and solid waste streams that end up as alternative fuels at cement plants, but the biggest fractions are generally concrete, followed by bricks. The recycled concrete is then typically used as an aggregate, either in new concrete production or in areas like road construction and earthworks. The use of recycled aggregates (RA) made from CDEW goes back to at least the 1930s in its current form although ‘reusing’ materials from structures such as castles and churches goes back far further. Recycling and reusing CDEW gained a boost in 2020 when the European Union (EU) set a 70% recovery target. However, within the EU the CDEW recycling rates vary considerably and that 2020 target includes the use of CDEW in backfill applications.

In its launch statement for Regenera, Cemex noted that it operates a dock in Paris, where it receives a variety of materials, including construction debris, excavated material and inert soil. These materials are sorted, processed and then transformed into recycled aggregates or organic material used to restore quarries. Cemex then promptly followed up the official launch of Regenera on 30 January 2023 with the acquisition of a majority stake in Shtang Recycle, an Israel-based CDEW recycling company. It added that Shtang Recycle is preparing to build a recycling plant with a production capacity of 0.6Mt/yr of CDEW waste materials. The output from the plant will be used as raw materials for aggregate production.

The focus on CDEW recycling was flagged up at Cemex’s investor event in November 2022. It said that it was targeting a recycling rate of 14Mt/yr of construction and demolition waste by 2030. Other managed waste stream goals included doubling the amount of municipal and industrial waste it manages, to achieve a 50% to fossil fuel substitution rate, and increasing its usage of alternative raw materials and by-products by 30%, thereby eliminating 13Mt/yr of extracted materials.

Cemex is not alone in targeting the CDEW waste sector. Holcim’s recent work in the area goes back to at least 2016 when a recycling unit near its Retznei cement plant in Austria started processing 130,000t/yr of CDEW. It announced in December 2022 that it was setting up a similar recycling centre, also in Austria, at its Mannersdorf cement plant. In October 2022 Holcim acquired Wiltshire Heavy Building Materials in the UK. This company recycles 150,000t/yr of construction and demolition waste into aggregates and concrete. Holcim linked the acquisition to its Strategy 25 target of recycling 10Mt/yr of construction and demolition waste by 2025.

Activity by other cement companies includes the commissioning of a construction waste recycling plant at Gennevilliers in France by CRH-subsidiary Eqiom in April 2022. It was aiming for a target of 50,000t in 2022. In November 2022 Heidelberg Materials agreed to acquire RWG Holding based in Berlin, Germany. Then, in December 2022, it announced a deal to buy Mick George Group in the UK. Both proposed acquisitions are subject to competition authority approval. Heidelberg Materials’ current target is to offer circular alternatives for half of its concrete products by 2030.

The moves by the bigger cement companies into the CDEW sector follow sustainable thinking and the waste hierarchy. Yet the big prize here is to gain a route to dispose of some of their CO₂ emissions through recarbonation and this has been flagged up in several net-zero roadmaps for the cement sector such as those by Cembureau and the Global Cement and Concrete Association (GCCA). Holcim has been involved in the FastCarb project in France, running a pilot at its Val d’Azergues cement plant in 2021. Heidelberg Materials has been testing its own process with so-called recycled concrete paste. The development now appears to be that utilising CDEW has entered the sustainability strategies for some of the big cement-concrete-aggregate producers, targets have been set and acquisitions are happening.

For more information on Heidelberg Materials research into concrete recycling read the January 2023 issue of Global Cement Magazine

UK: Hanson has announced a 'carbon capture breakthrough' in its use of recycled concrete paste (RCP) in the wet scrubber of its Ribblesdale cement plant in Lancashire. In under 30 minutes, 15t of RCP was able to capture 1.5t of CO₂ from the plant's flue emissions. Carbonated RCP is suitable to replace limestone in cement production.

Hanson's sustainability director Marian Garfield said “The trial was carried out with our parent company Heidelberg Materials’ research and development team, and marks another important milestone in our carbon capture journey."