Influence of fibre aspect ratio on rheological performance for 3D printable materials

• Main Author: Angellee, Raymond Rafael
• Other Authors: Qian Shunzhi
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: Engineering::Civil engineering::Construction technology
• Online Access: http://hdl.handle.net/10356/78783
• Institution: Nanyang Technological University

The concept of 3D printed materials has been widely used in the industries of present era. In particular, the construction sector is not unfamiliar with the term 3D printed concrete (3DPC). Improvements on the pumpability of concrete mix during printing have been continuously researched. However, fibre, a material widely researched in the mixture of common concrete mix, has not yet to be discussed upon regarding its influence towards 3D printed concrete. The process of 3D printing concrete involves several parameters, that include static and dynamic yield stresses, plastic viscosity, and thixotropy. These features are called the rheological properties. These critical parameters affect the process of how concrete mix flows out and settles upon printed. The experiment finds that higher fibre content contributes to higher value of static and dynamic yield stress and demonstrating decreasing trend for plastic viscosity. On the other hand, longer fibre unit contributes to decreasing trend of both yield stress while showing an upward trend for plastic viscosity. Both of these cases appear to show low thixotropy as the mass and length increase. Further research to implement the aspect of strength is needed, whereby a balanced result can be obtained by optimising the best out of both rheological properties and compressive strength of resulting concrete. In addition to that, a thorough procedure with exact timing for experiments should be taken note to avoid risk of cement settling before any test is carried out.