<p>When houses are printed with concrete cement what replaces the steel rebar for reinforcement?</p>
<p>Here's a link referencing printing concrete: <a href="https://www.aniwaa.com/house-3d-printer-construction/" rel="nofollow noreferrer">https://www.aniwaa.com/house-3d-printer-construction/</a></p>
<blockquote>
<p>House 3D printers use extrusion technology. Some construction 3D printers look like super-sized desktop FFF/FDM 3D printers (gantry style), whereas others consist of a rotating mechanical arm.</p>
<p>In both cases, paste-type components such as concrete are used as filament. The material is pushed out of a special nozzle to form layers. To put it (very) simply, paste extrusion is similar using a piping bag to spread frosting on a cake.</p>
<p>The printer creates the foundations and walls of the house or building, layer by layer. The ground is literally the printer’s build plate. Some concrete 3D printers, however, are used to 3D print brick molds. When molded, the bricks are then piled atop each other manually (or with a robotic arm).</p>
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<p>Like most of the people here my experience is with a printer (RepRap) that can use PLA or ABS. With all the materials normally put into concrete, using an extrusion printer to print concrete is puzzling.</p>

[{'answer_id': 8632, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 2, 'selected': False, 'text': "<p>The extruder can't push anymore when the filament is past the extruder gear. If your filament has run out to that point, the print will <em>not</em> halt but print without a filament, meaning that the print will fail. You need to pause the print in time and then put fresh filament into the printer.</p>\n\n<p>If the end of the filament is cut flat at the end and the new one is flat too, the new filament can push the old one out to the nozzle, reducing the waste to a minimum, if you can live without retraction for the amount of length that has to be used up. You could friction weld the two parts together to alleviate this.</p>\n"}, {'answer_id': 9774, 'author': 'Levi Giesbrecht', 'author_id': 14700, 'author_profile': 'https://3dprinting.stackexchange.com/users/14700', 'pm_score': 2, 'selected': False, 'text': "<p>When the end of the filament is beyond the reach of the hobbed stepper gear, your print will stop extruding. Some printers (i.e. Prusa i3, Craftbot 3, etc) have runout sensors. These sensors can be a switch or some form of a circuit that is broken when the filament isn't there to close it (I'm no mechatronics engineer or anything, so my terminology may be a bit off). When these switches are tripped, the printer automatically pauses the print, allowing you to come and rescue it. Fancier printers like the Craftbot 3 will actually send you an email when your filament runs out <em>or even jams!</em> Of course, that machine is over $3600CAD, and well out of most peoples price range. The Ender 3, being around 300 dollars, is not equipped with a runout sensor. Switches and 3D printing files to make your own are either cheap or free.</p>\n\n<p>And yes, some filament may need to be wasted if you do a swap. Direct drive extruders have the same problem but at a much smaller scale. If you just feed new filament into your machine, you will lose all retraction (which is annoying) until the second length of filament is in. At the point where the filament switches, (depending on your extruder and print speed) you may get a small patch of under extrusion. Nothing that will seriously compromise part strength, but it won't be super pretty.</p>\n\n<p>Hope that helps!</p>\n"}]
['https://3dprinting.stackexchange.com/questions/8635', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/15075/']