Page 40 - MSAM-1-3

Materials Science in Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Optimizing of chemical admixtures for 3D

printable cementitious materials by central
composite design

3
Mingyang Li , Yiwei Weng *, Zhixin Liu , Dong Zhang , Teck Neng Wong 1
1
1
2
1 Singapore Centre for 3D Printing, Nanyang Technological University, Singapore
2 Department of Building and Real Estate, The Hong Kong Polytechnic University, Hong Kong, China
3 College of Civil Engineering, Fuzhou University, Fuzhou, China

Abstract

Printability of 3D printable cementitious materials is related to material rheological
properties, and is affected and controlled by modern concrete chemical admixtures.
In this work, the influence of several chemical admixtures including superplasticizer,
retarder, and accelerator on the rheological characteristics of printable materials was
investigated using central composite design (CCD). Twenty test points with varying
dosages of chemical admixtures were performed to evaluate the primary effects
of chemical admixtures and their combined interactive effects on the rheological
properties. The results indicate that with the increase of retarder or superplasticizer
dosage, all rheological parameters decrease while accelerator possesses an opposite
impact. The rheological properties are negatively proportional to the combined
interactive effect of retarder and accelerator. The combined interactive effect of
retarder and superplasticizer positively affects dynamic yield stress, plastic viscosity,
*Corresponding author:
Yiwei Weng and thixotropy, while it negatively impacts static yield stress. The combined
(yiwei.weng@polyu.edu.hk) interactive effect of accelerator and retarder positively affects the yield stress,
whereas it negatively influences the plastic viscosity and thixotropy. The results
Citation: Li M, Weng Y, Liu Z,
et al., 2022, Optimizing of chemical indicate that the CCD is an efficient method to find the desirable formulation within
admixtures for 3D printable a given boundary.
cementitious materials by central
composite design. Mater Sci Add
Manuf, 1(3): 16. Keywords: 3D concrete printing; Central composites design; Rheological properties;
https://doi.org/10.18063/msam. v1i3.16
Statistical models
Received: July 30, 2022
Accepted: September 4, 2022
Published Online: September 21,
2022
Copyright: © 2022 Author(s). 1. Introduction
This is an Open Access article The 3D concrete printing (3DCP) technique, an extrusion-based additive manufacturing
distributed under the terms of the [1-3]
Creative Commons Attribution process , has attracted much attention in recent years due to its advantages, such as
License, permitting distribution, automated process, formwork-free construction, and improved productivity [4-6] . These
and reproduction in any medium, benefits are mainly due to the automated layer-by-layer construction process based on a
provided the original work is
properly cited. 3D model. In the printing process, material rheological performance is a critical factor
determining the printability of printed structures [7-9] .
Publisher’s Note: Whioce
Publishing remains neutral with Printability is characterized by buildability and pumpability, which are related
regard to jurisdictional claims in to material rheological properties (static/dynamic yield stress, plastic viscosity, and
published maps and institutional
affiliations. thixotropy) [10,11] . These parameters are affected by various factors, including material

Volume 1 Issue 3 (2022) 1 https://doi.org/10.18063/msam.v1i3.16