ENVIRONMENTAL AWARENESS
Recycled concrete crucial for Net Zero challenge
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Concrete refurbishment innovation has key role to play in the sustainability of the UK’s future built environments according to Dr Steve Holmes, of SIKA
reating low carbon or even Net Zero buildings is achievable – we know how to design and build them and have the materials to do so. The major challenge
is how we approach the maintenance, upkeep and refurbishment of the more than 45 million existing buildings in the UK. Finding a solution to this issue could have a real impact on the UK government’s ambitions for a Net Zero future. Employing sustainable materials to repair and maintain, rather than demolish our vast estate of concrete structures contributes significantly to sustainability targets. Concrete repair is big business. Indeed, it’s predicted that the concrete repairs mortars market will be worth USD 4.0 billion by 2026, which represents a five-year compound annual growth rate of 8.7%.1 With ever-tighter project deadlines and environmental targets to meet, the current climate requires customers to demand more from their concrete repair systems. Hence, there is an increasing need for products which are more cost-effective, minimise refurbishment times and result in a more sustainable repairs programme.
Innovation and sustainable concrete repair
Corrosion inhibitors have been setting the standard for future emission-reducing refurbishment practices. Surface-applied liquid or slow-release vapour-phase inhibitors penetrate concrete and form a passive layer around the steel reinforcement. Inhibitors delay the corrosion process and reduce its rate. They can also reduce or remove the need for more carbon-intensive operations on site. This simple time and cost-effective practice can prolong the life of a building and extend gaps between maintenance cycles by up to 15 years when used as part of a complete repair and protection system.
Galvanic repair solution
Sacrificial galvanic anodes represent another environmentally-friendly option when it comes to addressing ongoing reinforcement corrosion in concrete structures, or extending the life of concrete repairs. Targeted use can minimise the need for concrete removal or other material/ machinery intensive operations, leading to an overall reduction in carbon emissions. The anodes comprising a zinc core encased in a small, cementitious shell are installed within concrete repairs to prevent incipient anodes developing in adjacent, unrepaired areas. They can also be installed outside of the repaired areas in cored holes to protect the reinforcement in chloride-contaminated, but as yet undamaged concrete. With a galvanic sacrificial anode system, the reinforcement can be hand or mechanically prepared by wire brush or abrasive paper. This means grit or water-blasting can be avoided, reducing waste, fuel and environmental pollutants.
Recycling concrete
Good quality concrete repairs which are sustainable and effective over the long-term will be crucial to reducing the construction industry’s ecological footprint, as will reducing waste. This is a major challenge as a European Commission report2 revealed that 25-30% of all waste generated in the EU comprises construction demolition waste materials, much of which could have been recycled. To address the waste issue, Sika has developed
a process for recycling old concrete rather than sending it to landfill. Involving a method that is as simple as it is effective, old concrete is broken down into individual parts: aggregate, sand and fine powdered materials - which also binds about 60kg of CO2 per ton of crushed concrete demolition waste. This innovation - with the brand name «reCO2ver» – allows the separated components to be reused in new concrete. The process increases the recycled aggregates’
Sika Limited and Sika Ireland Limited are part of the global Sika Group, specialising in the manufacture and supply of chemical based products. Sika specialises in the development and production of systems and products for bonding, sealing, damping, reinforcing, and protecting in the building sector and the motor vehicle industry. The company has subsidiaries in 100 countries around the world and manufactures in over 300 factories. With more than 25,000 employees Sika generates annual sales of CHF 7.9 billion (£6.14 bn).
In the UK and Ireland, we provide solutions for concrete, waterproofing, roofing, flooring, refurbishment, sealing & bonding, and industry, and have manufacturing sites in Welwyn Garden City, Preston, Leeds, Wishaw and Dublin with more than 920 employees and a turnover of more than £290 million.
16 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JULY 2022 Read the latest at:
www.bsee.co.uk
quality, whilst comparative testing of the Sika «reCO2ver» method proves that new concrete containing recycled content performs similarly to an all-new product. Innovations such as Sika’s recycled concrete solution are giving specifiers much to consider when thoughts turn to sustainable construction materials and creating a built environment that is less impactful in terms of CO2 emissions.
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