Freeze-Thaw-Resistance of 3D Printed Composites with Desert Sand (2022-07)¶

The reasonable utilisation of local desert sand for manufacturing 3D-printed concrete is sustainable and contributes to the advancement of 3DCP to achieve its maximum environmental potential. In this study, desert sand was used to prepare 3D-printed concrete by optimising the sand and cementitious binder (S/C) ratio. The influence of the S/C ratio on the printability and mechanical properties was investigated, and the relationship between interfacial porosity and mechanical anisotropy was revealed; furthermore, the mass loss, relative dynamic elastic modulus, and interfacial porosity after exposure to 300 freeze-thaw cycles were systematically investigated and analysed. The evolution characteristics of the internal pore structure of 3D-printed desert sand concrete under freeze-thaw cycles were studied, with particular emphasis on elucidating the freeze-thaw influence on both interfacial and matrix porosities. Subsequently, a thaw damage degradation model under different S/C ratios was constructed. The results proved the applicability of a mixture with an S/C ratio of 1.70, which had the best mechanical performance and met the desired requirements for freeze-thaw resistance.