Engineer Steve Merritt explores the potential that advanced materials offer to develop 3D printed buildings sooner, rather than later.
3D printing has exploded from an expensive and niche concept to a well-known and easily accessible activity. Printers for home use can be purchased almost as affordably as petrol these days. When discussing 3D printing you might think of resins and filaments, but you wouldn’t immediately think about concrete. In 2019, however, Dubai was inducted into the Guinness Book of World Records for the construction of a 3D printed building project of 640m2.
Whilst we call the printing of concrete 3D printing, it is technically regarded as ‘additive manufactory’, but that has less of a ring to it. Additive manufactory is an interesting concept for future structures, as it accelerates the assembly time of projects which would usually take many months, and completes them over the course of hours or days. This reduction in time and increase in automation allows for more cost-effective construction of complex structures, freeing budget for inspection and maintenance protocols and – more importantly – reducing costs whilst maintaining profits.
A challenge that asset integrity has always faced when working with concrete structures is the corrosion of embedded steel rebar, which can lead to the structure’s failure. Unfortunately, steel rebar is necessary, as traditional concrete isn’t capable of independently withstanding tensile loads. This challenge may, however, be overcome by use of engineered cementitious cement, a composite material based upon concrete that displays pseudo-ductile properties. In short, it is strong enough to build with, and flexible enough to stand without steel rebar support. But most importantly, it can be used in additive manufactory, making affordable 3D printed structures with improved durability a possibility sooner, rather than later!