Cambridge researchers, in collaboration with industry partners, have achieved a significant milestone in the field of 3D printing by developing the first-ever 3D-printed concrete infrastructure. This groundbreaking project involved creating a 3D-printed head wall, which was installed on the A30 road into Cornwall as part of a National Highways initiative.
The unique aspect of this 3D-printed structure lies in its incorporation of sensors that provide real-time data on various measurements, including temperature, strain, and pressure. These sensors enable the head wall to function as a “digital twin,” allowing for early detection and prevention of potential failures or issues before they occur.
Traditionally, headwall structures are constructed using precast concrete with extensive steel reinforcement and formwork. However, the Cambridge team, along with specialists from Costain, Jacobs, and Versarien, utilized 3D printing technology to design and build a curved hollow wall without the need for formwork or steel reinforcement. Instead of relying on steel for strength, the geometry of the wall itself provides structural stability.
The 3D-printed wall measures approximately 2 meters in height and 3.5 meters in width. It was printed at Versarien’s headquarters in Gloucestershire using a robotic arm-based concrete printer. This innovative approach significantly reduces costs, materials usage, and carbon emissions compared to traditional construction methods.
Professor Abir Al-Tabbaa’s team at Cambridge University has been working on sensor technologies for infrastructure monitoring for several years. Their expertise includes developing “smart” self-healing concretes and integrating sensors into structures to enhance data collection. For this project, they supplied temperature sensors to monitor thermal behavior during the printing process.
By continuously monitoring temperature variations within different layers of the 3D-printed wall during construction, potential hot spots or anomalies can be identified promptly. The collected temperature data will be correlated with thermal image profiles to gain a comprehensive understanding of the wall’s thermal behavior.
Due to the embedded sensors, the head wall can also provide measurements of relative humidity, pressure, voltage, electrical resistivity, and electrochemical potential. These readings offer valuable insights into the reliability, robustness, precision, and longevity of the sensors themselves.
Likewise to sensor integration, a LiDAR system was used to scan the wall while it was being printed. This scanning process generated a 3D point cloud and created a digital twin of the structure. The digital representation enhances its ability to communicate information about its own condition and aids in further research on 3D-printed structures.
The Cambridge team developed a specific type of sensor called PZT (Piezoceramic Lead-Zirconate-Titanate) sensors for this project. These sensors measure electromechanical impedance response and monitor changes over time to detect any potential damage or deterioration. They play a crucial role in assessing how mortar hardens over time and monitoring the In the main health of the structure.
During the 3D printing process, eight PZT sensors were embedded within different layers of the wall to capture load presence and stress levels during construction and throughout its lifetime in operation. To facilitate data collection from these sensors remotely, an innovative wireless data acquisition system was developed by the team.
Professor Al-Tabbaa emphasizes that this project will serve as an ongoing “living laboratory,” generating valuable data throughout its lifespan. The combination of data from both physical sensors and the digital twin will provide infrastructure professionals with better insights into how 3D printing can be utilized for larger-scale projects involving complex cement-based materials within strategic road networks.
The multidisciplinary team involved in this project includes experts in smart materials, automation and robotics, data science, as well as industry partners such as Costain and Versarien. Their collaboration has paved the way for future advancements in 3D printing technology applied to infrastructure construction and monitoring.
According to experts, this groundbreaking achievement demonstrates the potential of 3D printing in revolutionizing the construction industry. As technology continues to advance, it is expected that 3D printing will play an increasingly vital role in creating sustainable and efficient structures.
In essence, Cambridge researchers, in partnership with industry leaders, have successfully developed a 3D-printed head wall with integrated sensors. This innovative project showcases the possibilities of 3D printing technology for constructing concrete infrastructure while providing real-time data for monitoring structural health. The combination of sensor technologies and digital twin capabilities opens up new avenues for improving infrastructure design, construction, and maintenance. With ongoing research and development in this field, 3D printing is poised to transform the future of construction.
