Transporting to a greener future

Civil Engineer Jack Tregartha argues that adopting new methods of working within the construction industry - BIM, 3D printing, the use of recycled materials - can help the industry achieve net-zero carbon emissions by 2050.

How can we use more sustainable tools in construction?
How can we use more sustainable tools in construction?

Global warming is caused by the release of carbon dioxide (green-house gases) into the air when hydro-carbon fuels such as coal, oil, wood, petrol, diesel, gas etc are burned.

According to the UK Green Building Council, around 10% of the country’s carbon dioxide emissions are directly associated with construction activities. The number rises to 45% when taking into account the whole of the built environment sector.

If current greenhouse gas emissions stay at the current level, we are heading towards a three to four degree celsius rise in average temperatures which would have a catastrophic impact on the environment. We would experience significant heat events and sea levels rising, causing severe floods. There would be less fresh water available and many eco-systems will struggle meaning species become extinct. According to NASA estimates, all but one of the 16 hottest years in NASA’s 134 year record have occurred since 2000.

This tells us we need something to change now.

The task ahead

First, let’s look at the actual targets which have been set. The end goal by 2050 is to achieve net- zero carbon emissions with an intermediary goal of 50% reduction by 2025. (all relative to 1990 emission levels). We need to reduce the amount of carbon dioxide through the full life span of infrastructure and buildings from inception through to disposal. We need to be designing and constructing projects which meet the demands of today with limited impact on the future.

I believe the following factors are key to achieving the task.

1. Minimise wastage on construction projects

I believe the introduction of building information modelling (BIM) to the industry coupled with the emergence of 3D printing and ‘off-site’ construction will help significantly reduce the amount of waste that we produce on engineering sites.

In particular, for complex buildings where varying quantities of different types of materials are required, a ‘5D’ BIM model can help accurately quantify the materials required for use on the project and I believe this will then be able to be inputted into a 3D printing system which can increase the amount of work which is carried out off-site and decrease the amount of work which is required on site.

2. Reduce embodied carbon in construction

We should be using a selection of recycled materials which have a lower carbon intensity such as cement substitutes. Cement has a significant embodied carbon trail and we all know how vital this product is to construction projects. Metakaolin, Silica Fume, Nano Silica and Calcium Hydroxide are all working examples of bonding agents which have a significantly reduced carbon footprint than cement. An awareness of these sorts of products needs to be more embedded to allow contractors to make these decisions moving into projects.

3. Value engineering methodologies on site

For example, construction heads should be working in close liaison with the client/principle designer to maximise the potential re-use of materials on site. An example of this would be utilising excavated material for the construction of embankments, etc. The excavated material could then be improved by using lime or cement to enable the material to meet the desired specification, thus minimising the export to a landfill site which can be costly and increase carbon emissions significantly. Another form of value engineering would be the selection of materials for use in the permanent works, for instance a plastic pipe has a small carbon footprint and can be 100% recyclable.

4. Better engagement and communication

There should be a better engagement with the supply chain to achieve ultimate buy-in from everyone involved on the project. Effective communication with suppliers (be it labour, plant or materials) is essential to prevent excess or incorrect materials being sent to site or maybe a skip being collected that's only half full.

In conclusion I believe construction has a massive role to play in the significant reduction in carbon emissions. Small actions all contribute to build momentum to achieve this ambitious but realistic target.

References:

  1. https://www.wwf.org.uk/updates/our-warming-world-how-much-difference-will-half-degree-really-make
  2. https://climate.nasa.gov/effects/
  3. https://www.nrdc.org/stories/global-warming-101
  4. https://www.newcivilengineer.com/the-future-of/towards-net-zero-rising-to-the-carbon-challenge-17-01-2020

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