Building sustainability into infrastructure

Tuesday 12 April • Viewing time: 1 minute

We’re improving safety and sustainability in bridges in the UK and abroad, through our development of both new materials and new inspection software.

Bridges are some of the most ambitious and expensive infrastructure projects in the world — and they have a sizable carbon footprint to match.

For the last ten years, I’ve led a team to develop a new maintenance and construction material which makes them safer, longer-lasting and more sustainable.

We’ve also standardised the training of government bridge engineers and inspectors, and created unique software to help them carry out their vital work.

The problem with concrete

After water, concrete is the most consumed resource in the world.

The manufacture of its key ingredient, ordinary Portland cement (OPC), is responsible for 10% of global carbon emissions. To put this in context, if the cement industry were a country, it would be the third biggest emitter of carbon dioxide in the world.

Once in place, concrete shrinks, cracks, and needs regular repairs. It’s also porous, so chlorides from substances like road salt can move through it and corrode steel reinforcements.

Maintaining concrete structures like bridges has often relied on the application of more concrete. To put a stop to this vicious cycle, we looked for a more sustainable alternative.

A non-cement solution

With funding from the European Commission and industry, we built on existing research to develop a brand new material. Crucially, we then took it out of the laboratory and into industry, by licensing the material for commercial use.

Our alkali-activated concrete material (AACM) or geopolymer is made from sustainable industrial waste materials. It reduces carbon emissions by 70% compared to ordinary OPC solutions.

As the AACM binds to deteriorated concrete, we can use it to mend existing concrete structures. It is resistant to fire, cracking and corrosion, so the repair lasts far longer.

We’ve also found an application for the material in a process called cathodic protection. This involves using an AACM-coated anode which creates a current to migrate corrosion away from steel reinforcement.

Aside from maintenance, AACM can also be used as a construction material in itself. Buildings around the world are using fire-resistant AACM lintels for safety, which don’t require the same fireproof coating as their concrete equivalents.

Whatever the application, the material extends service life and helps organisations avoid demolitions.

Maintenance modelling

The data we gathered from our research led us to create modelling software for a new bridge management system.

When a bridge inspector carries out their inspection and tests, they input the data into our software. It then analyses the condition of the bridge by determining the severity and extent of any defects, to provide a score which is used to make decisions on maintenance.

The research was funded by the Department for Transport and the system is now used by 343 councils in England, as well as by governments in Wales, Scotland, the Isle of Man, Qatar, Cyprus, Dubai, Albania and Malaysia.

The software applies our research specifically to the requirements of the Management of Highways Structures code of practice, and the Inspection Manual for Highway Structures produced by the UK Bridges Board.

This consistency is key. It means that a bridge being inspected in the UK will get a similar score as a bridge in the same condition in another country. This ensures the same high standard of safety across the industry.

And being able to provide fair evidence of the state of their bridges has helped local authorities gain equitable government funding to maintain their bridges.

Leading a more sustainable industry

Our materials and modelling software are helping lead the industry towards a more sustainable future. But we’re also bringing about efficiency and lasting cultural change through staff training programmes.

We lead the training scheme for the professional registration of bridge inspectors, which is now mandatory in England, Scotland and Wales.

We’ve held 2,500 training days for delegates across the UK. Feedback has demonstrated how our training increases competency, safety and environmental awareness.

Our ever increasing reliance on concrete is damaging the planet — but the worldwide interest in our training, software and materials shows hope.

We’re now working with authorities in one of the most populous and industrialised countries in the world, India, to embed sustainability into their infrastructure too.