Nanomaterials as Promising Additives for High-Performance 3D-Printed Concrete: A Critical Review

Abstract

Three-dimensional (3D) printed concrete (3DPC), as one of the subset of digital fabrication, has provided a revolution in the construction industry. Accordingly, scientists, experts, and researchers in both academic and industry communities are trying to improve the performance of 3DPC. The mix design of all kinds of concrete has always been the most crucial property to reach the best efficiency. Recently, many studies have been performed to incorporate nano- and micro-scale additives to ameliorate the properties of 3DPC. The current study aims to present the main design properties of 3DPC and completely cover both fresh and hardened state characteristics of 3DPC containing different nano- and micro-additives. Our observations illustrate that nanomaterials can be mainly utilized as a thickener to ameliorate the thixotropic behavior and the structural build-up of 3DPC, resulting in higher yield stress and better viscosity recovery. Furthermore, each nanomaterial, through its unique impact, can provide lower porosity and permeability as well as better mechanical strengths for 3DPC. Although much research investigate the fresh properties of 3DPC containing nano and micro additives, future studies are needed to provide better insight into the impact of these kinds of additives on the hardened characteristics of 3DPC. In addition, researchers may devote more research to address the effects of the additives discussed herein on the performance of other kinds of 3DPC such as lightweight, self-compacting, etc. It should be noted that the effect mechanism of nanomaterials on the inter-layer bond strength of 3DPC is another crucial issue that should be investigated in future studies. Furthermore, nano-scale fillers from source of waste and biomass can be attractive additives for future research to achieve high performance of sustainable 3D-printed concrete.

Synergism of Artificial Intelligence and Techno-Economic for Sustainable Treatment of Methylene Blue Dye-Containing Wastewater by Photocatalysis

“…This SDG could also be improved by conducting essential research on the management and/or disposal of exhausted ZnO/MgO photocatalysts. For Instance, Razzaghian Ghadikolaee et al [56] found that the photocatalyst material after exhaustion could be managed by using it as an attractive additive to maintain better 3D-printed concrete properties.…”

“…Applying these eco-friendly and cleaner techniques to synthesize the ZnO/MgO could reduce the chemical costs and minimize exposure to possible material toxicity. Where the recyclability of the spent catalyst material is concerned, the ZnO/MgO nanocomposite should be tested for applications as an additive in the construction industry, following previous research [56]. This benefit would avoid the unrestricted disposal of solid waste to the terrestrial and inland freshwater ecosystems and the related services, meeting the targets of SDG15 "Life on Land".…”