News | Friday, 12th November 2021

COP26: Can 3D printing concrete help solve the world's sand crisis?

Sheryl Lee explains how sand used for construction is running out across the globe

Representatives from Manchester Met are attending COP26 to help accelerate action to tackle climate change. We'll be sharing our insights and research that is making a difference over the duration of the conference.

By Sheryl Lee, Research Associate in the Faculty of Science and Engineering.

Is the world running out of sand?

Sand is used in everything from our buildings and roads, to glass products like windows and TV screens.

As our population expands, and living habits change, we are using more sand than ever before in construction and production of buildings and materials – in fact, the amount of sand we need to keep up with this growth is quite astounding.

Globally, we use 50 billion tonnes of sand every year for these reasons.

As more people change their lifestyles to live alone – which requires having their own building, their own windows and products that would have been used by a whole family before, more sand is needed. World-wide population growth means more housing and infrastructure as well.

What is interesting is, when we talk about needing more, this isn’t just any old sand. Take desert sand – if we could build with this, that would be great as we have so much of it – but we can’t as the grains are too round. It would be like trying to build with marbles.

For construction, we need sharper sand as it stacks better. This can be found in marine beds, river beds and the ground – so it needs to be quarried.

One thing that is probably quite surprising to people is the fact that there is actually a global shortage of this kind of sand. It’s not so much that we are running out, it’s that we are running out of convenient sand we can access.

Because of this, massive amounts of sand is stolen – complete beaches and even islands have been taken, from South East Asia, all the way to the Caribbean. Sand is dredged and removed to be sold on the market for construction purposes. 

From a crime perspective, in some countries there are gangs land grabbing and stealing sand from villages, meaning locals are losing things like farmland and housing as well as being put in danger from gang related activity.

Closer to home, quarry sites are having to expand due to the increase in demand and this is impacting communities here in the UK who are being subjected to the dust and noise that these quarries produce.

An environmental issue

The global issue concerning sand is an environmental one, although it’s not a common issue we think of when we think of the environment and sustainability. 

We have been dredging sand so much, it’s actually altering water courses, destabilising river banks and changing local eco-systems by destroying habitats and eroding beaches. The extent of the damage is unknown as the size of the problem has yet to be calculated, it is clear however that it is increasing rapidly in line with demand.

Once we have taken the sand from the land or the sea, there is also a vast amount of energy needed to transport that to where it is needed. It needs to be washed, screened and treated, which all requires water and energy – so overall, there are lots of implications.

That is why, if we can find a way to reuse demolition waste – so the concrete and materials we already have and no longer need – we are winning on all fronts.

How 3D printing concrete can help

We use 54 million tonnes of marine sand in North West Europe alone, every year, for the purpose of producing concrete for construction.

We also have 65 million tonnes of recycled fine aggregates (RFA) – crushed demolition waste – which is either being landfilled or used as backfill.

At Manchester Metropolitan University, along with partners across Europe, we are currently working on a project, which will hopefully see this RFA reinvented and made into new, custom made infrastructures using 3D printing.

By thinking of new ways to recycle the waste from demolished buildings, we hope to not only reduce the amount of waste being landfilled, but also reduce the dredging of sand, which is unsustainable and causing damage to fragile marine beds and life.

For the project – named CIRMAP – we are researching how to make the perfect 3D printing cement mortar from RFA we have collected from the local region.

Currently, concrete cannot easily be recycled for use within the construction industry as materials that make up RFA are so varied, meaning the material does not meet strict building regulations.

RFA can also become contaminated during the demolition process, making it difficult to reuse.

However, 3D printed products are not subject to the same building restrictions, which is why they could provide a solution for the reuse of RFA.