Going, going greener

Concrete specification can have a major role to play when construction companies are looking to incorporate a more environmentally friendly stance into their operations. Barry Mellor highlights the benefits of Lytag – one of the greenest options on the construction scene

Balancing the need for economic growth with sustainability remains one of the most pressing challenges facing the modern construction world.

According to latest figures, around 33 per cent of UK carbon emissions come from the built environment, including raw material production, construction, operation, maintenance and decommissioning1.

To tackle the problem head on, in November 2017, the UK government struck an agreement with the industry to reduce the cost of construction by one-third while halving greenhouse gas (GHG) emissions in the industry by 20252.

The landmark deal will see the government invest £170m over three years, with £250m coming from industry, to commercialise technologies capable of building energy-efficient, cost-effective housing and infrastructure3. More recently, the UK became the first major economy to commit to bringing all greenhouse gas emissions to net zero by 20504 – and the construction sector is expected to play a vital role in this.

The result is mounting pressure on architects, developers and contractors alike to improve the carbon footprint of new buildings. Often this starts with the procurement of environmentally friendly building materials – and innovative concrete solutions are increasingly leading the way in meeting ever-stringent sustainability targets.

Sustainability criteria
At present, the most prominent sustainability assessment and certification process in the UK is the Building Research Establishment Environmental Assessment Method (BREEAM), which uses everything from energy, transport, water use, materials, waste and pollution to establish a building’s green credentials.

When it comes to building materials in particular, there are many reasons that concrete remains the most widely used man-made material in the world today; durability, high-compressive strength, fire resistance and versatility. However, given the greater onus on the industry on achieving a high BREEAM status, this has certainly driven demand for ‘greener’ concrete solutions.

‘Green’ concrete
For instance, recent years have seen the growing use of concrete made from secondary aggregate – materials which would otherwise become landfill – which in accordance with BREEAM specifications means it can be counted towards the recycled aggregate content of a build project.

A great example of this is Lytag, a lightweight aggregate made from fly ash generated by coal fired power stations. Using pioneering technology, the fly ash is transformed into round pellets, which are then heated to 1,100°C to create incredibly hard, durable aggregate pellets. Ranging in size from 14 mm down to fines, each of the pellets consists of a honeycombed internal structure of interconnecting voids, making Lytag both structurally robust and lightweight.

What’s more, it replaces the need for quarried natural aggregate and in doing so can reduce CO2 emissions in buildings by up to ten per cent as by being up to 50 per cent lighter than natural aggregate, it means fewer truck journeys are needed to transport construction materials – resulting in significant cost savings for the build.

As a result, Lytag, which this year celebrates its 60th anniversary, has been instrumental in helping developers to achieve exceptional BREEAM standards on many of the UK’s most iconic construction projects including Canary Wharf (2000), the Gherkin (2001) and the Shard (2012).

Lighten up
And it’s not just in the capital; during the recent construction of Midlands Metropolitan Hospital, Birmingham’s new £370m super hospital, Lytag proved essential to meeting the project’s stringent sustainability requirements.

Indeed, integral to the project is an overriding onus on sustainability with the building earmarked to be in the top ten per cent of non-domestic building in terms of sustainable performance, achieving a BREEAM rating of very good or higher on completion. Luckily, by using Lytag the finished building was able to achieve this.

Structural advantages
In addition to its stellar environmental credentials, due to its unique composition, Lytag also affords contractors and structural engineers a raft of other invaluable benefits, such as reducing the number and size of columns, in order to create bigger structures with greater spans, whilst at the same time being able to reduce the total load of their builds.

Crucially, it’s also important to note that the lightweight material offers the same level of structural performance as standard weight concrete, which given its other advantages has allowed developers to make the seemingly ‘impossible’ possible by giving the industry greater freedom to than ever before to push the boundaries of modern architectural design.

Lytag takes the load off
The recent construction of the 2 Semple Street, a new upmarket commercial build in Edinburgh city centre, clearly demonstrates Lytag’s unrivalled ability to facilitate ground-breaking design.

To achieve the project’s aim of building 45,000 sq ft of cutting-edge office and retail space, over five storeys, a key requirement was sourcing a concrete solution which would enable minimal size slabs and help reduce the overall dead load of the building.

Thanks to its superior lightweight and robust properties, Lytag was the obvious choice and effectively reduced the composite deck concrete slab load by approximately 25 per cent over normal weight control, whilst offering the same high level of structural performance. This was supported with a robust delivery framework ensuring that all batches arrived on time and to the exact specification – thus preventing the risk of cold joints.

A concrete conclusion
Amid recent reports showing that almost two-thirds of businesses operating in the UK construction sector are now more committed than ever before on taking action on sustainability5, the direction of travel for the industry is clear – reducing carbon emissions needs to be at the heart of everything we do. For many, the answer lies with looking at all aspects of a project, whether it’s the supply chain and associated infrastructure or the integration of energy efficient technologies and systems.

However, frequently at the top of the agenda is the use of sustainable material choices, where solutions such as Lytag, which is not only making the transition to ‘greener’ construction much more efficient and cost-effective, but is also leading the way in world-class architectural design.

1, 2, 3 https://www.edie.net/news/6/UK-construction-industry-agrees-to-halve-emissions-by-2025/
4 https://www.gov.uk/government/news/uk-becomes-first-major-economy-to-pass-net-zero-emissions-law
5 https://www.edie.net/news/7/UK-construction-industry-accelerating-action-on-sustainability/

Barry Mellor is commercial manager at Lytag. Lytag is an Aggregate Industries business and benefits from the resources and capabilities of a highly skilled research and development team, as well as the financial and global business strength of its holding company Holcim.
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