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Today the Built Environment department's concrete printer starts printing the world's first 3-D printed reinforced, pre-stressed concrete bridge. The cycle bridge will be part of a new section of ring road around Gemert [Netherlands] in which the BAM Infra construction company is using innovative techniques.
[O]ne of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mold is filled. By contrast, a printer deposits only the concrete where it is needed. This has benefits since in the production of cement a lot of CO2 is released and much less of this is needed for printed concrete. Another benefit lies in freedom of form: the printer can make any desired shape, and no wooden molding frames are needed.
They have managed to not only 3-D print concrete, they have also developed a technique to lay down a cable within the concrete so that it can be 'pre-stressed' — avoiding tensil stress.
The researchers successfully tested a 1:2 scale model under a 2000kg load.
(Score: 3, Informative) by Immerman on Friday June 23 2017, @03:08PM (1 child)
Granted, simple shapes like spheres, and even hollow "eggs" aren't incredibly difficult to cast, though they will still add substantially to the cost - takes a lot more man-hours to build the forms for a fairy castle than for a rectilinear slab. Where 3D printing gets *really* interesting is in doing things like honeycombed interiors, which can give you most of the strength of a solid casting while using almost as little material as a hollow casting.
And obviously the initial designs will be fairly conservative - radically new designs that exploit the advantages of a new manufacturing technology take a lot of time and effort to develop, and are particularly risky when the claimed advantages haven't actually been thoroughly tested in the real world. Give them some time - once the new technologies have been tested and proven in terms of strength, durability, and cost-effectiveness, then the architects will begin to explore its non-traditional capabilities far more fully.
(Score: 0) by Anonymous Coward on Friday June 23 2017, @03:45PM
There is a potential danger with using so little concrete in a "bracing" manner rather than a solid, bulk manner: the concrete in the "less material is used" structure is suddenly more critical. If it cracks or weathers away, failure will happen sooner than with a bulk cast concrete structure.