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HARD HITTERS COMMENT M ARCH AUGUS 2021 T 2019
PRINTING THE FUTURE DR. MUSTAFA BATIKHA, ASSOCIATE DIRECTOR OF RESEARCH AT THE HERIOT-WATT UNIVERSITY DUBAI’S SCHOOL OF ENERGY, GEOSCIENCE, INFRASTRUCTURE AND SOCIETY, DISCUSSES THE PROS AND CONS OF 3D CONCRETE PRINTING AND THE WAY AHEAD
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rapidly growing population is one of our biggest challenges in the 21st century. Recent data from the United Nations confirms that the world’s population will reach 9.7 billion in 2050 with an average yearly increase rate of 0.84% between 2010 and 2050. With this population growth, it is predicted that the global construction industry will record a compounded annual growth rate (CAGR) of 5.7% to reach about $12tr trillion by 2024. Governments around the world are under enormous pressure due to a shortage of affordable housing. For example, the UAE government has taken the initiative of launching The Emirates Development Bank (EDB) with $2.7bn aimed at financing affordable residential projects for UAE citizens by 2021. On the other hand, there is a demand for addressing important issues in the construction
sector, such as sustainability and health and safety, in the backdrop of rapid and cost-effective construction. Thus, the construction industry is in need of new innovative construction technologies such as 3D Concrete Printing (3DCP), which is paving the way for meeting future requirements. Understanding the technique 3DCP was developed to build a structure upwards through a series of layers, one on top of another through a robotic arm or a gantry girder system. The concrete material in this technology is the printer’s ink, while a nozzle attached to the printing system plays the printing mechanism’s role. The final output is a layer of concrete of the desired shape and thickness. Printer selection plays a vital role in terms of cost and printing quality. For example, the robotic arm offers better flexibility since it has six degrees of freedom. It also allows superior quality in printing for precise, complex printed shapes. Its limitation is the limited arm length. Also, the operation and maintenance of the robotic arm make printing cost
higher than the gantry girder by about three times. The robotic arm’s biggest disadvantage is that the printer has an unstoppable process until the element is fully printed. Therefore, design errors will produce material wastage. However, the selection of the printer is defined based on the printed structure’s type. Advantages of 3DCP 3DCP in construction avoids the disadvantages of in-situ reinforced concrete (RC), such as excessive construction waste, formwork cost (which comprises more than 60% of the overall cost), formwork preparation time (which takes up 50% to 70% of the total construction duration), and the lack of worker health and safety (where workers’ injuries in in-situ RC construction are double the accidents registered by other industries). WinSun, a pioneer of 3D printing technology in construction, claimed that the labour cost of their ‘Office of the Future’ project in Dubai was reduced by more than 50% when compared to conventional buildings of similar sizes.
