The most widely used building material in the world.
Ready-mixed concrete is the most widely used building material in the world. It is essential to society and a cornerstone of our built environment. It is flexible, versatile, durable, and strong, and is used in a wide variety of applications including housing, commercial buildings, road building and major infrastructure projects such as bridges, tunnels, and airports as well as energy and water plants.
It also absorbs CO2 throughout its life and is 100 per cent recyclable, contributing significantly to the circular economy and providing materials with lower embodied carbon.
Concrete manufacturers, like Hanson UK, take their responsibility to reaching net zero carbon very seriously and have roadmaps in place to achieve the Government’s ambitious 2050 deadline.
Hanson’s route to decarbonisation has been ongoing for many years and the company has made significant progress, including reducing its CO2 emissions in the UK by more than 50 per cent since 1990. But its ambition of reaching net zero carbon emissions by 2050 can only be made a reality if carbon capture and storage (CCS) technology can be utilised.
This is because cement is a key ingredient in concrete and its production is energy-intensive, with Hanson’s cement business responsible for 90 per cent of all of its CO2 emissions. Of these emissions, around 70 per cent are form the chemical processes involved in cement’s production, which cannot be reduced by using lower carbon or renewable energy sources. As a result, the only way to produce the cement needed without emitting large amounts of carbon is to capture and store these emissions, removing them from the process completely.
To this end, Hanson UK is proposing to invest around £400 million to build an industry-leading carbon capture facility at its Padeswood cement works, near Mold in north Wales. It would capture the CO2 produced during cement manufacture before it enters the atmosphere, transporting it via the HyNet Northwest underground pipeline and storing it safely under the seabed (see article in NEWS section.
Carbon capture is a safe and proven technology that has been around for many years in other industries. It is already being developed by Hanson’s parent company Heidelberg Materials in Belgium, Canada and Norway and the Group will capture and store 10 million tonnes of CO2 cumulatively until 2030 through the CCUS projects it has in development.
Padeswood CCS could set the UK construction industry on a path to achieving the Government’s binding net zero targets by capturing and storing 800,000 tonnes of CO2 each year and will enable Hanson to produce net zero carbon cement as early as 2027.
Hanson is also involved in an additional carbon capture project at its Ketton cement works in Rutland. The multi-industry project, part of the Government’s Net Zero Innovation Portfolio, will see C-Capture’s carbon capture technology implemented at several sites across the country. The process uses a solvent to selectively capture the CO2 produced and requires less energy than some other carbon capture technologies, with the potential to significantly reduce its cost. The feasibility study is now complete, and the demonstration unit is expected to be installed later this year.
A third carbon capture process, conducted with Hanson’s parent company Heidelberg Materials’ R&D team, has also been demonstrated at its Ribblesdale cement works in Clitheroe, Lancashire. Here, the team proved that enforced carbonation of recycled concrete paste (RCP) within the plant’s existing wet scrubber allows for a high CO2 uptake within less than 30 minutes, preventing emissions entering the atmosphere.
During the trial 15 tonnes of industrial RCP were fed into the scrubber resulting in 100kg of CO2 being bound within each tonne of RCP. It confirmed the feasibility of enforced carbonation, which supports the circular economy by using waste recovered concrete fines to remove CO2 emissions from the production process while producing a secondary material that can then be used to replace virgin limestone in cement and concrete production.
The Ribblesdale trial follows one conducted under semi-dry conditions at Heidelberg Materials’ Brevik plant in Norway and marks another important milestone in the company’s carbon capture journey.
In order to make it easier to access low carbon concretes now, Hanson has developed its EcoCrete range, which reduces the CO2 emissions associated with standard CEM I concrete by at least 30 per cent.
EcoCrete concretes contain Regen GGBS (ground granulated blast furnace slag), a by-product of ironmaking, as a replacement for some of the cement content in concrete. Using GGBS reduces the embodied CO2 in a concrete mix by around 780 kg for every tonne of CEM I Portland cement it replaces. It also increased the long-term durability of structures, conserves natural resources for future generations as it does not require the quarrying of materials, and prevents the slag bring disposed of as landfill.
There are three products in the range: EcoCrete, which reduces CO2 by 30-64 per cent compared with CEM I concrete; EcoCrete Extra, which reduces CO2 by 65-79 per cent; and EcoCrete Elite, which reduces CO2 by at least 80 per cent.
Hanson is already the largest producer of low carbon concrete in the UK and its involvement in these industry-leading projects demonstrates its commitment to developing new technologies to support the construction industry in reducing the embodied carbon in building projects and helping meet net zero goals.