As demand for eco-friendly homes and stricter regulations grow, Andy Campling of Tarmac explores how manufacturers are tackling the challege of developing low-carbon concrete solutions that could transform UK housebuilding.
While the construction industry’s path to net zero is becoming more hopeful due to increased innovation and transparency, it’s still a path that is challenging to travel. Stringent environmental regulations and the growing demand for environmentally friendly homes are putting immediate pressure on housebuilders to make sustainable changes rapidly to keep pace. Low carbon concrete solutions are enabling housebuilders to meet this pressure head-on, transforming construction’s sustainability landscape.
Concrete’s climate problem
On the road to net zero, construction is facing a myriad of unique challenges that are making sustainability goals a marathon, rather than a sprint. One of the main challenges posed to the industry is the issue of concrete. Concrete is a major source of CO2 in construction, accounting for 1.5% of all emissions in the UK – and 8% globally.
In recent years, the focus on environmental legislation has shifted to building materials and reducing carbon emissions. Significant changes include but are not limited to the Future Homes Standard 2025, the Labour government’s housing development pledge, and the Net Zero Carbon Buildings Standard. Combined, these three changes demonstrate a growing emphasis on embodied carbon, CO2 emissions associated with materials, and construction processes throughout the entire life-cycle of a building or infrastructure.
Housebuilders must evaluate the environmental impacts of a building or development throughout its life-cycle, then make a change. The most recent and accepted evaluative standards for embodied carbon are found in building life-cycle assessments (LCAs). LCAs highlight the relevant regulatory compliance for embodied carbon, opportunities to reduce embodied carbon, and the embodied carbon data to declare in Scope 3 emissions.
The rise of low carbon concrete
The demand for low carbon concrete has been steadily increasing and concrete manufacturers are innovating to meet this need. Low carbon concrete is produced with fewer carbon emissions compared to standard concrete while maintaining the same properties that make concrete a reliable building material.
The reduction of carbon comes from manufacturers using alternative materials to clinker, such as fly ash, slag, or limestone. These alternatives have been extensively proven to be high-quality materials that are safe and effective in reducing the carbon footprint of concrete production. For instance, Tarmac uses only the highest quality alternative materials and follows strict quality control measures to ensure that our low carbon concrete meets and exceeds industry standards.
Additionally, low carbon concrete has been shown to be more durable and resistant to corrosion than traditional concrete and just as strong, if not stronger depending on the specific mix design and intended application. Low carbon concrete can offer better long-term strength and durability, making it a great option for long-lasting structures.
However, some manufacturers are also creating tailored, low carbon concrete. For example, at Tarmac we engineer all our CEVO low carbon solutions, so whatever your performance requirement, we can supply a reduced CO2 concrete solution, depending on the rating you want to achieve (from industry standard A++ to G).
The perceived upfront cost of low carbon has been a known barrier for housebuilders who are aiming for net zero but have budgetary constraints. But, as with many sustainable changes within the industry, the cost-effectiveness of low carbon must be seen on a long-term basis. Understanding and talking about how the long-term benefits of low carbon’s durability and sustainability can save money overall, will make this shift less challenging and seen as an inevitable move to make sooner rather than later.
Innovations in concrete
Many manufacturers welcome the update to the BS 8500 British concrete standard, which allows for portland-limestone (PLC) cements to be used in combination with GGBS. PLC cements allow up to 20% of the cementitious elements to be limestone filler, replacing clinker and lowering the carbon emissions from cement. PLC has been a major focus in Tarmac’s concrete solutions evolution and we have planned a full rollout across our national manufacturing capability.
Additionally, Tarmac has developed an alkali-activated material system (AACM) which has been used in recent full-scale demonstrations across the UK, including a National Highways project on the M42. We anticipate the replacement of CEM I 52,5N (PC) volumes, with CEM II A-LL 52,5N (PLC), a UKCA-marked cement with limestone filler already built in, which can be used under the new BS 8500 standards. Tarmac has confidence that CEM II A-LL will have equivalent performance, creating a permanent carbon-cutting replacement.
Low carbon concrete is a relatively new technology and it’s still evolving to meet the demands and challenges of the construction industry. But as sustainability becomes an essential element to housebuilding, low carbon concrete becomes a vital product that needs to be readily available in order for it to be a viable choice for housebuilders.
Looking ahead
Concrete’s path to net zero is hopeful. Despite the building material’s reputation for being a significant contributor to carbon emissions, there is an exciting solution emerging with the increasing popularity of low carbon concrete. With regulations constantly evolving and the rising demand for eco-friendly housing, low carbon materials are slowly becoming the go-to for housebuilders.
Manufacturers are innovating with alternatives to clinker and engineered solutions are allowing tailored mixtures to meet environmental standards. Low carbon concrete is transforming housebuilding in the UK and ultimately leading the industry to a more sustainable future.
Andy Campling is head of readymix performance at Tarmac