Understanding and mitigation of plastic shrinkage cracking in 3D-printed concrete elements
Final Report Abstract
There is great potential for 3D concrete printing to revolutionize the construction industry. An essential step toward transferring this new technology into practical application is gaining the ability to control and mitigate plastic shrinkage in printed elements and related cracking. These phenomena occur very early after the deposition of concrete, primarily due to the absence of formwork. The cracks can negatively impact the printed structures' durability, serviceability, and aesthetics. The overall objective of this project was to gain a deeper understanding of the mechanisms of plastic shrinkage deformations and related cracking in 3D-printed concrete elements. However, measuring concrete shrinkage in its plastic state is fraught with many challenges. Remarkably, none of the existing methods for quantifying plastic shrinkage (PS) and plastic shrinkage cracking (PSC) can be directly adapted to printable concretes without impairing their intrinsic properties. Moreover, the applicability of existing mitigation approaches for shrinkage-induced deformations and related cracking should be revised in the context of 3D printing technology. Therefore, this project aimed to accomplish the following main goals: 1. Develop adequate experimental approaches for quantifying plastic shrinkage and resulting cracking in 3D-printed concrete. 2. Develop accurate experimental methods to determine genuine material properties such as bulk modulus, coefficient of permeability, water retention, tensile strength, and degree of hydration in the context of extrusion-based selective material deposition. 3. Simulate plastic shrinkage and cracking by utilizing the aforementioned material properties and experimentally verify the simulation results for free and restrained plastic shrinkage using the developed setups. 4. Analyze the cracking mitigation methods based on the simulations and experiments conducted and assess their efficiency.
Publications
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Modelling the development of capillary pressure in freshly 3D-printed concrete elements. Cement and Concrete Research, 145, 106457.
Ghourchian, Sadegh; Butler, Marko; Krüger, Markus & Mechtcherine, Viktor
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Optical 2D-measurement of unrestrained plastic shrinkage in 3D-printed concrete elements, Biot-Bažant Conference, Northwest ern University, Evanston, Illinois (2021]
V. Markin & V. Mechtcherine
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Measuring Plastic Shrinkage and Related Cracking of 3D Printed Concretes. RILEM Bookseries, 446-452. Springer International Publishing.
Markin, Slava & Mechtcherine, Viktor
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Rissbildung in 3D-gedruckten Betonelementen infolge plastischen Schwindens: Ursachen und Quantifizierungsmethoden. Beiträge zum 61. Forschungskolloquium mit 9. Jahrestagung des DAfStb, 115-120. TU Dresden.
Markin, Slava & Mechtcherine, Viktor
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Effectiveness of Paraffin-based Curing Compound for Mitigation of the Plastic Shrinkage and Related Cracking of the 3D-printed Concrete Elements. 16th International Conference on Durability of Building Materials and Components. CIMNE.
Markin, S. & Mechtcherine, V.
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Evolution of capillary pressure in 3D-printed concrete elements: numerical modelling and experimental validation. Construction and Building Materials, 409, 133677.
Markin, Slava; A., L. Cordova Julian & Mechtcherine, Viktor
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Methods for measuring plastic shrinkage and related cracking of 3D-printed concrete. Journal of Physics: Conference Series, 2423(1), 012036.
Markin, Slava & Mechtcherine, Viktor
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Quantification of plastic shrinkage and plastic shrinkage cracking of the 3D printable concretes using 2D digital image correlation. Cement and Concrete Composites, 139, 105050.
Markin, Slava & Mechtcherine, Viktor
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The Effect of Layer Cross-Section on Plastic Shrinkage Cracking of 3D-Printed Concrete Elements. Lecture Notes in Civil Engineering, 300-309. Springer Nature Switzerland.
Markin, Slava & Mechtcherine, Viktor
