Abstract
In concrete structures realized by digital fabrication techniques, such as 3D concrete printing, under severe dynamic loadings (e.g. earthquakes and impact loads), the strength at the bond interfaces between layers is weak. Since these contact zones, also referred as cold joint, could potentially compromise the structural stability and also the durability of printed elements, their behaviour under high dynamic loads is fundamental to investigate. An experimental program on 3D printed concrete elements varying the waiting time, through medium and high strain-rate tensile tests is running, with a Hydro-Pneumatic Machine and a modified Hopkinson tensile bar respectively. The results of dynamic tensile tests at three different strain rates (10-5, 50 and 200 s-1) on 3D printed cementitious elements for waiting times of 0min, 10min and 30 min have been presented, in terms of Dynamic increase factors DIF versus strain rate, showing a behaviour highly strain-rate sensitive, recording an increase in tensile strength DIF up to 7.6 in the case of high strain-rate and waiting time of 30 min. The results exhibited a decrease in the dynamic interface tensile strength with the waiting time up to over 90% for a medium strain-rate and over 20% for a high strain-rate.
Highlights
IntroductionAdditive manufacturing (AM) technologies, such as 3D-printing or layered extrusion technique, are arousing an increasing interest in the construction sector, and in particular in the concrete application, for fabricating 3D structures directly from a digital model in successive layers usually layer upon layer [1]
Additive manufacturing (AM) technologies, such as 3D-printing or layered extrusion technique, are arousing an increasing interest in the construction sector, and in particular in the concrete application, for fabricating 3D structures directly from a digital model in successive layers usually layer upon layer [1].The adoption of additive manufacturing technologies potentially brings a number of advantages [2], but at the same time suffers from a number of drawbacks, which limited their spread
Tensile test results can be used to investigate the behaviour of the unprinted and printed concrete subjected to a dynamic regime, at different strain rates and characterized by different waiting times
Summary
Additive manufacturing (AM) technologies, such as 3D-printing or layered extrusion technique, are arousing an increasing interest in the construction sector, and in particular in the concrete application, for fabricating 3D structures directly from a digital model in successive layers usually layer upon layer [1]. The adoption of additive manufacturing technologies potentially brings a number of advantages [2], but at the same time suffers from a number of drawbacks, which limited their spread. The layered extrusion technology necessarily creates interfaces between subsequent deposited layers, namely “Cold Joint”. These surfaces might create a potential zone of weakness into the printed structures [3] and depend mainly on the waiting time, i.e. the time between the printings of two successive layers [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
