An ab initio approach for thixotropy characterisation of (nanoparticle-infused) 3D printable concrete

This paper presents a novel theological thixotropy model that specifically appertains to the characterisation of materials that are suitable for 3D printing of concrete (3DPC). The model accounts for both physical and chemical influences on a material's microstructure, denoted by R-thix (re-flocculation) and A(thix). (structuration) respectively. Rheological analyses are performed on a reference material with varying superplasticizer (SP) and nano-silica (nS) dosages in order to determine their effects on the aforementioned parameters. Specific focus is placed on the re-flocculation thixotropy mechanism. The advantages of adding nanoparticles to concrete for 3DPC is practically validated by printing circular hollow columns until failure occurs. The result is supported by the thixotropy model, which is applied to the materials that are used for the 3DPC tests. It is concluded that, for this study, R-thix is a better measure of thixotropy behaviour that is suitable for 3DPC than A(thix). (C) 2019 Elsevier Ltd. All rights reserved.