Abstract
Lightweight foam concrete (LWFC) has relatively high workability, or low static and dynamic shear resistance in the fresh state. It is also sensitive to applied pressure. These limitations present challenges for 3D printing of LWFC, through its pumping and extrusion, and bearing pressure of subsequent layers. The associated risks of 3D printing LWFC is therefore twofold, altering the LWFC properties during the printing process, and insufficient buildability. Inclusion of appropriate nanoparticles, with high surface area to volume ratio, is proposed here to influence the microstructure of the cementitious composite in the fresh and hardened state, in order to increase the shear resistance, and limit the impact of the 3D printing process on its density. Nano-SiO2 (nS) particles with a diameter smaller than 30 nm and 99.5% purity are incorporated into LWFC at 2% and 3% by weight of cement. Rheometer results indicate increased shear resistance and thixotropic behavior. Conservative buildability prediction based on the thixotropic properties is validated by 3D printed nLWFC building height of a circular hollow column.
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Cho, S., Kruger, J., van Rooyen, A., Zeranka, S., van Zijl, G. (2020). Rheology of 3D Printable Lightweight Foam Concrete Incorporating Nano-Silica. In: Mechtcherine, V., Khayat, K., Secrieru, E. (eds) Rheology and Processing of Construction Materials. RheoCon SCC 2019 2019. RILEM Bookseries, vol 23. Springer, Cham. https://doi.org/10.1007/978-3-030-22566-7_43
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DOI: https://doi.org/10.1007/978-3-030-22566-7_43
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