Lightweight foam concrete (LWFC) is becoming an interesting structural material. In its fresh state, LWFC is highly flowable. Modification of the rheology is required to include 3D construction printing as a production process for this class of materials. Nanoparticles have…
Lightweight foam concrete (LWFC) is becoming an interesting structural material. In its fresh state, LWFC is highly flowable. Modification of the rheology is required to include 3D construction printing as a production process for this class of materials. Nanoparticles have been shown to improve thixotropy of cement-based materials, characterized by a high static yield shear stress, but a distinctly lower dynamic yield shear stress. In this paper, 2% nano-silica (n-SiO2) by mass of cement content is added to LWFC, and the consequential improved 3D printability validated by actual 3D printing of laboratory specimens. A systematic experimental study is performed to characterize the mechanical strength and stiffness, as well as fracture energy of n- SiO2 LWFC, against control LWFC without n-SiO2. The n-SiO2 specimens are prepared by both casting and 3D printing, in order to also investigate the influence of the layered 3D printing process, including the cohesion of the interfaces between layers. The mechanical strength, stiffness and fracture energy of n-SiO2 LWFC are shown to be significantly higher than control LWFC specimens without nanoparticles.