Engineering company Laing O’Rourke is addressing the challenge of climate change by embracing new products and processes.
A sense of urgency is driving change at Laing O’Rourke right now, said Hollie Hynes, the company’s General Manager, Sustainability and Environment.
The urgency is driven by the organisation’s Global Sustainability Strategy, set in 2021.
That strategy has already influenced change on sites around the globe, including in the processes the company followed and the materials it has chosen.
In August 2021, for example, Victoria’s Department of Transport and Planning (DTP) confirmed that, for its Level Crossing Removal Projects (LXRP), it would approve on a case-by-case basis mixes with a higher proportion of cement replacement than allowed in its standards.
Specifically, the Australian Roads Research Board (ARRB), on behalf of DTP, approved a mix with 70 per cent cement replacement with industrial by-products such as fly ash and slag. This is 30 per cent higher than the 40 per cent limit in the standard and 55 per cent higher than the LXRP business-as-usual (BAU) rate of 15 per cent.
This change, which will prevent the emission of about 4000 t of carbon dioxide over three sites, might have been impossible had there not been a program alliance model in place, one that encompasses collaborative contracting.
And with the LXRP project having now grown to 110 crossings, the positive effect should scale significantly.
“In a traditional contract model, you go to tender and businesses bid and the bidders that don’t win are reimbursed,” Hynes said.
“It’s roughly a four to five-month process to even bid [for] the job and a nine-month process to be awarded. If you did that for 110 projects consecutively, we’d still be bidding in 2090 and beyond. So the client has been smart and wrapped this up into a program alliance, which helps accelerate the work.”
There are a lot of efficiencies to be gained from doing several projects at the same time, and from the same alliances moving on to the next projects.
In the Laing O’Rourke alliance, known as the South Eastern Program Alliance (SEPA), are LXRP, Jacobs and Metro Trains Melbourne.
“We’ve completed six level crossings to date, including four at the beginning that weren’t formally part of the alliance program,” Hynes said. “We also have another five we have been awarded that we are developing with the client.
“Three of the projects in delivery are using this mix, showcasing how we are able to create sustainable solutions that have ongoing benefit, not just for LXRP but the broader industry.
“That’s the second important point of this collaborative contracting model. When you are in a program alliance, and the client is in the tent with you, there are no barriers to sharing innovations or ideas, and we’re incentivised to put everything on the table.
“It fosters an environment in which innovation, sustainability and early adoption are incentivised and rewarded financially, so innovations are shared and best practice quickly spreads across sites.
“I cannot stress enough how contract models are going to be the maker or breaker of the transition to 2050.”
Tried and tested
Such a model was also a success when used by the Stronger Christchurch Infrastructure Rebuild Team (SCIRT) in the years following the 2011 New Zealand earthquake.
On that project, numerous stakeholders were “in the tent”, including Canterbury Earthquake Recovery Authority, Christchurch City Council and NZ Transport Agency, alongside engineering and construction firms City Care, Downer, Fletcher, Fulton Hogan and McConnell Dowell.
Businesses were rewarded for adhering to a set of performance measures that included innovation and collaboration. Cost penalties were shared among all teams, meaning high performers were incentivised to boost the success of others.
The result was a higher pace of recovery for the city as well as greater innovation.
“There has been a lot of innovation in Christchurch since the earthquake,” said Professor Suzanne Wilkinson, now with Massey University but at the time Director of the Centre for Disaster Resilience, Recovery and Reconstruction, in a 2016 interview.
“The first is around SCIRT and the way it uses an alliance approach to take on a massive horizontal rebuild. That, in itself, was an innovation. Without SCIRT, Christchurch’s recovery would have been much slower.
“SCIRT also set a key performance indicator for innovation, for each building team. This was one of the KPIs linked to the reward of future work packages. It meant innovation was very visible and helped foster innovative practices.
“It was also exciting for us, as the innovation KPI created over 600 innovations for us to research.”
Low-carbon concrete
Did the use of concrete containing a lower-carbon cement mix — one produced with 70 per cent of its cementitious material replaced with fly ash and slag — bring engineering challenges?
“There are some differences,” Hynes said. “But one of my team members, when I was talking with them about it, said it was quite unremarkable in itself.
“There’s a programming consideration because it takes longer to cure initially. It’s not horrifically slow, but it does need to be taken into consideration.”
During the pilot program to test the new mix, it was poured in the sub-structure. This was most suitable, as piles are often poured early but are not load-bearing until later in a program.
This gave the team time to allow the concrete to cure and to further test its properties.
In many ways, the lower-carbon concrete was better than the BAU mix.
“It’s more durable with regards to chemical attack and corrosion, and its lower heat of hydration, while reducing early-age strength development, reduces risks from thermal cracking as the concrete sets,” Hynes said.
“This mix could be used for slabs — it can be designed to meet all the key performance requirements — however, we would need to conduct more investigations and possibly implement more controls.”
The team started with the biggest opportunity area for this project: the piling.
“If it’s proposed for use in a slab, it has higher finishing requirements and can’t be loaded for a longer time period. We need to start factoring that in when we budget,” Hynes said.
“You can still use it, but what’s most important is that we’re now very comfortable in using these mixes for substructures.”
Alliance help
Laing O’Rourke worked closely with the SEPA team to identify the concrete mix, its use cases, and a supplier, Holcim Australia.
The client, having been a part of the entire discussion, authorised the concession to use the mix.
Once tested on the live project, which was the Union Road and Mont Albert Road level-crossing removal project, it was immediately approved for use for piles on the next three projects.
On these, 50 per cent of the concrete, or about 18,000 m3, will be in piling.
“Our sustainability team and our engineering team worked out the areas of greatest materiality in this job and over the next three jobs,” Hynes said. “We were able to make some decisions that were going to have [a] large, scalable impact rather than impact on just one job.
“The client’s maturity and confidence around the importance of this has evolved along the way. It went from incentivising Green Star and Infrastructure Sustainability Council ratings to incentivising the areas of real materiality — reduction in tonnes of carbon — and saying actually, we’re now incentivising you to find solutions that don’t exist at the moment.”
For Laing O’Rourke itself, a powerful part of its sustainability journey so far has been in developing an understanding of its own emissions profile.
“Scope one and two emissions are well known for us — fuels and electricity — but scope three is much more difficult. They are the emissions that result from the activities of assets not owned by us,” Hynes said. “We committed to truly understanding our scope three in 2019 and realised that it is now 95 per cent of our emissions profile.
“Concrete — and I know this is a big estimate — is responsible for 20 to 50 per cent of our scope three emissions. And we believe it’s at the higher end of that scale.
“That’s why we decided on concrete as our first area of focus, and that’s why we’re so proud of our progress so far.”