STRUCTURAL ELEMENTS 81
MASONRY’S ROLE ON THE ROAD TO NET ZERO
Miles Hogg of Lignacite explores how concrete masonry has evolved to meet the demands of the 2050 net zero deadline.
O
ver the years, concrete masonry has evolved to meet many challenges, including carbon reduction targets for buildings and increasingly demanding acoustic standards. Now it is faced with a new challenge: to embrace and positively improve sustainability performance in its journey towards net zero.
Concrete masonry – a description for all types of concrete blocks and bricks – is the most widely used wall material in the UK. Masonry solutions in new housing account for around 80% of the housing maret but its use is not ust confi ned to this sector. There is also strong demand in the commercial, educational, leisure and retail sectors.
CONCRETE & CEMENT EMISSIONS According to the Mineral Products Association (MPA), concrete and cement currently account for around 1.5% of the UK’s carbon dioxide emissions. Thanks to early action by the industry, this is fi ve times lower than the global average (7%), but there is still far more that can be done. The MPA has also reported that the UK’s carbon dioxide emissions from concrete and cement stood at 7.3 million tonnes in 2018. This can be broken down into the following areas:
• Around 4.4 million tonnes of ‘process emissions’ from clinker production • 2.2 million tonnes from fuel combustion • 0.7 million tonnes from electricity use and transport.
From this, it is easy to see that clinker production is the main source of carbon emissions in the cement and concrete industry. Clinker is the principal ingredient in cement, which forms one of the main components in concrete. Clinker’s emissions arise from the combustion of fuels in the kiln and from process emissions, which are a by-product of the chemical reaction that produces clinker.
Compared with other industries, the masonry sector uses relatively little cement in its products. For example,
of a cement kiln is safe and has a limited impact on the environment. According to the MPA, decarbonising the electricity grid will encourage the electrifi cation of the industry reducing its reliance on fossil fuels. Using technol- ogies such as plasma energy and CCUS (carbon capture, usage, and storage) could increase the industry’s electricity use by 80% to 130%.
THE BENEFITS OF CARBON CAPTURE, USAGE & STORAGE
the cement content of a common dense block is usually between 6% and 10% of the total mix by weight, depending on the manufacturer. However, for every tonne of cement produced, around 622 kilograms of CO2
is emitted, and it
remains an important contributor to the masonry sector’s carbon footprint. To address these emissions, the cement industry has an ambitious plan to go beyond net zero by 2050. This will
result in a signifi cant reduction in CO2 emissions which will directly benefi t all cement users, including the masonry sector. Below are just some of the initia- tives planned or already underway for reduction in cement carbon emissions.
PROCESS IMPROVEMENTS
Process improvements include invest- ment in new plant and manufacturing techniues such as artifi cial intelligence (AI) and automation. This will help to reduce waste with more streamlined and carefully monitored production. Alternative fuels, coupled with substan- tial investment in new technology, have already helped cement manufacturers to mae signifi cant reductions in their ey emissions between 1990 and 2011. More and more UK cement plants are now routinely using carbon-neutral fuels as a substitute for virgin fossil fuels, including treated household and commer- cial wastes, solvents, scrap tyres and pelletised sewage sludge. Each of these materials has a high caloric value and would otherwise go to landfi ll or inciner- ation without energy recovery. Burning them in the extremely controlled settings
UK investment in infrastructure and successful industry research has enabled the use of CCUS. This transformative technology represents the most signifi cant and technically disruptive investment in the roadmap, creating the potential for a massive CO2
reduction of 61% by
2050. However, several hurdles need to be crossed fi rst including additional research, and the political issue of unfair carbon prices.
LOW CARBON CEMENTS Traditionally, an effective way of reducing the carbon footprint of cement was to replace it with a proportion of supple- mentary cementitious materials (SCMs). These are primarily ground granulated blast furnace slag (GGBS) or pulverised fl y ash . sed in abundance by the masonry industry, these industrial waste products are unfortunately declining in availability, which means that other SCMs need to be investigated.
REDUCING EMISSIONS IN CONCRETE MASONRY
The government’s ‘Net Zero Strategy: Build Back Greener’ set out policies and proposals for decarbonising all sectors of the UK economy to meet the nation’s net zero target by 2050.
The concrete masonry sector, part of the wider precast and concrete industry, has therefore adopted the UK Concrete and Cement Industry’s ‘Roadmap to Beyond Net Zero.’
Although roadmaps are vital in setting out the vision, it will be up to individual sectors and businesses to create their own
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