Preparation and Performance Characterization of Low-Density 3D-Printed Expanded Perlite–Foam Concrete

Abstract

Traditional lightweight foam concrete typically introduces a large number of voids into the concrete using surfactants to reduce density. However, in 3D printing, the instability of lightweight foam concrete can affect the workability of the slurry. Additionally, the lower strength of foam with more pores also reduces its mechanical performance. This study found that by replacing sand with expanded perlite in 3D-printed foam concrete, the stability of the foam is improved, enhancing the workability of the mixture and increasing the constructability of printed concrete. Furthermore, analyses of mechanical properties, porosity, and pore size distribution showed that at the same dry density, foam concrete with a higher expanded perlite replacement ratio exhibited higher compressive strength, with a maximum strength increase of up to 39%. Moreover, the introduction of expanded perlite optimized the pore distribution of the foam concrete, resulting in a more uniform material structure. The 3D-printed expanded perlite–foam concrete (3DPFC) prepared in this study provides new insights for the preparation of lightweight 3D-printed concrete, which is of significant importance for the sustainable development of the construction industry.