The exterior walls of a childcare center were 3D printed in two days in Singapore. The first story was made with additive while the second was made with conventional methods. This comes amid a push by Singapore to increase the number of early child care places available and to use 3D printed construction. The building is a part of a 348-apartment condominium project in Singapore’s northern Woodlands neighborhood. Woodlands is home to the excellent Marsiling Mall Hawker Centre, known for Ye Lai Xiang Laksa, the excellent Yan Ji Seafood soup, and nearby Nur’s Malay Food. Woodlands is residential, a high-rise kind of place replete with Housing and Development Board (HDB) apartments and their recognizable boxy style. With mangrove, a pair of parks, and sandwiched between Malaysia, a wetland, and the Zoo, it’s a nice place. There’s an Uniqlo, you’re very close to the cheap things and good food of Malaysia, but for Singapore, the place is relatively remote.
The structure was 3D printed by construction firm Woh Hup. Won Hup isn’t just any construction firm; started in 1927, it is one of the largest local firms and has worked on some of the most iconic and challenging local projects, such as Jewel Changi Airport, the Expo center, and the Gardens by the Bay. The company is now working on around 20 projects across Singapore, including a 63-story residential building, and another twin 62-story residential building with a third 36-story building next to it. Won Hup builds subway stations, golf courses, giant malls, and government buildings. The scope for additive is therefore considerable. As well as Won Hup, the National University of Singapore (NUS), the Building and Construction Authority (BCA), and the National Additive Manufacturing Innovation Cluster (NAMIC) worked on the project.
“(It) needs to be set up one day before casting, and can only be removed one to two days after concrete is cast. 3D concrete printing can reduce the amount of manpower involved, and offer a higher degree of design freedom for architects and structural consultants.”
He also stated that it is cheaper than formwork, the Straits Times said: “The walls on the first level of the centre were printed in two days, and required a team of around six construction workers tasked with responsibilities such as monitoring the sensors that track the quality of the concrete mixed on-site. Three additional checkers were also deployed to ensure that the novel process went smoothly. The work took a total of 170 manhours, whereas manual building would have required nearly 400 manhours and a larger team of 11.”
Now used as a structural element, concrete is advancing in Singapore. Compression, load-bearing, bending, and shear-bending were tested on the structure. One thing that was pointed out is that construction could take place later in the evening, resulting in less noise pollution, a benefit that I had not previously heard about. The 3D printed concrete also needed more cement and therefore a higher emissions overall concrete mix than regular concrete. Still, the team is trying to resolve this by using 60% glass powder in the mix. The Co2 emissions would be reduced by half, and their calculations show that it would retain the same strength.
The higher Co2 emissions are something that needs to be talked about more by the 3D printed concrete community. Just saying that it is more sustainable because it uses less material is not enough. And using glass powder in this way, readily available globally, could be a great boon to the 3D printing construction industry.