You are here: Innovative Thinking Digital twin helps speed concrete casting in Hong Kong 05 May, 2021 By Jackie Whitelaw
Evolution of a concrete “digital twin” combining sensors that detect curing rates with building information modelling has allowed one Hong Kong contractor to strike its pours 38% faster.
Covid-19 is regarded as the cause of an accelerated uptake of technology worldwide. And that is certainly the case in Hong Kong where in the last six months the construction industry has adopted a purely technical solution for determining concrete integrity by using sensors instead of crushing cubes.
The next step, described as a world first by Gammon Construction and construction technology pioneer Converge, has been to integrate sensors and building information modelling (BIM) via the new Converge ConcreteDNA Pro system. The technology creates a digital twin of concreting on site, offering real time visibility of pours, curing rates and productivity. Innovation versus labour shortages
Hong Kong’s £30bn a year construction sector has had impetus to adopt innovation well before the pandemic following publication of the government’s Construction 2.0 – Time to Change policy in September 2018. The policy’s launch was a signal to the Hong Kong construction sector that innovation and new technology had to be embraced to counteract labour shortages and to improve productivity.
Converge’s sensors have been in use around the world for the last four years including in Hong Kong on the Tuen Mun-Chek Lap Kok bridge and in London at City Airport.
For these projects, the sensors were cable tied to reinforcement in concrete frames and floor slabs and measured compressive strength of the concrete as it cured. Site engineers then collected the data via handheld devices.
But in the latest ConcreteDNA Pro iteration being used at Hong Kong Science & Technology Parks Corporation’s Advanced Manufacturing Centre (AMC) by Gammon Construction, the hardware uses a new cellular gateway dubbed the Signal Live Hub. This automatically transmits sensor data to the cloud in real time so no manual data collection is required.
The sensors give you confidence to strike the slabs earlier than you would with cubes
The real time sensor data links to a BIM model of the AMC concreting programme that is available on the ConcreteDNA platform and, along with added artificial intelligence-based predictions that are part of the package, creates a digital twin.
“We’ve gathered data from tens of thousands of sensors from several hundred projects in the past which has allowed us to create algorithms that predict when concrete will be up to strength so contractors can programme future pours,” says Converge chief executive officer Raphael Scheps.
ConcreteDNA Pro introduces concrete performance and temperature differential analytics to the platform which means project teams can track and ensure concrete is meeting expected standards, he says. Monitoring with BIM
“In the BIM model, pours are colour coded. We can see them developing strength, can see in real time what is done and not done, create average floor to floor cycle times, assess performance of different types of mix, compare progress on different days of the week or of different gangs and how close we are to hitting key milestones,” says Gammon executive director and chief technical officer Paul Evans.
“For me, this is all about generating productivity improvement. The sensors give you confidence to strike the slabs earlier than you would with cubes – up to 38% earlier, we have found.”
Gammon building director Sammy Lai can also see the benefits. “The AMC project team collects much less manual data from each pour, saving considerable manpower and avoiding potential human error. The curing predictions and notifications that a pour has reached the required strength also means the right people get to the right place at the right time,” he says.
“The contextual information for curing predictions has allowed our team to coordinate better, allocate resources more efficiently and mitigate project risks by planning ahead with better 4D oversight.”
There are also benefits in terms of carbon reduction. Gammon saved over 110t of concrete waste by not having to test approximately 14,000 cubes on the AMC project.
“Construction produces 11% of the world’s carbon emissions and 7% of the global total is from cement,” says Scheps. “Eating away at that is a real target for data and our sensors.”
With ConcreteDNA Pro we can bend the cost curve in favour of green [solutions] by reducing cost and raising productivity
Gammon and Converge can also see potential to use the data provided by the sensors and ever refined artificial intelligence to take mix design to the next level.
The goal is to reduce cement content in the concrete, again with an eye on emissions. That means looking at the mixes themselves to see how much cement is really needed and cut out any overdesign which will translate directly to reduced carbon cost, while opening opportunities to use less carbon intensive cement substitutes.
“There is usually a downside to greener, cement-free concrete because you lose productivity as it takes longer to reach strength. With ConcreteDNA Pro we can bend the cost curve in favour of green [solutions] by reducing cost and raising productivity,” Evans says.
Next steps involve enlarging the scope of the sensor technology and the digital twin. Delivery tracking
“As Hong Kong switches to more modularisation and design for manufacture under Construction 2.0, we will be working with Converge through our Digital G digital business to use sensors as part of the logistics set up, tracking prefabricated units through manufacture to delivery and installation on site,” Evans says. “We are still in the early days of collecting data on logistics but even now we are getting benchmarks to build into future tenders.
“We’ll also want to put in sensors to track structural stability, measuring tilt, movement, vibration and load. The vision is to optimise concreting, which links to logistics. That links to site productivity rates and then structural performance.
“At the moment we’ve got some challenges – Wi-Fi on site is variable, for instance, but that will change over the next couple of years. And the sensor batteries last for around three years. If we want to create a full digital twin with data being collected when the buildings are in use, they will need a much longer life.”
The next few years will require a culture change in construction, Scheps and Evans predict. “We have got to stop thinking like contractors. We’ll be logistics specialists for up to 70% of the time and we’ll need people who can interpret data to sharpen our abilities,” Evans believes.
The partnership with Converge has helped put Gammon on that path. As Gammon chief executive Thomas Ho says: “ConcreteDNA Pro has really enabled us to take strides in evolving our processes for the future of construction.”

This data comes from MediaIntel.Asia's Media Intelligence and Media Monitoring Platform.