Mechanical Properties of Short Fiber-Reinforced Geopolymers Made by Casted and 3D Printing Methods: A Comparative Study

Abstract

The main objective of this article is to develop ceramic-based materials for additive layer manufacturing (3D printing technology) that are suitable for civil engineering applications. This article is focused on fly ash-based fiber-reinforced geopolymer composites. It is based on experimental research, especially research comparing mechanical properties, such as compressive and flexural strength for designed compositions. The comparison includes various composites (short fiber-reinforced geopolymers and plain samples), different times of curing (investigation after 7 and 28 days), and two technologies of manufacturing (casted and injected samples—simulations of the 3D printing process). The geopolymer matrix is based on class F fly ash. The reinforcements were green tow flax and carbon fibers. The achieved results show that the mechanical properties of the new composites made by injection methods (simulations of 3D technology) are comparable with those of the traditional casting process. This article also discusses the influence of fiber on the mechanical properties of the composites. It shows that the addition of short fibers could have a similar influence on both of the technologies.

The influence of microstructure on mechanical properties of 3D printable geopolymer composites

“…These factors are important for the proper reactivity and good workability of this material during the geopolimerisation process. The specific density and fineness modulus of sand is 2.65 and 2.84, respectively [7].…”

“…They have many advantages such as resource saving, energy efficiency and friendliness towards the environment [3,4]. However, the full exploitation of additive technology for effective application in the construction industry still requires optimisation, especially with regard to improving methods of designing new materials [5][6][7].…”

“…Some of the most promising materials for 3D printing technology in the construction industry are geopolymers [4,7]. Nowadays, a lot of research works are conducted in this area, especially in the context of improving the key properties of additive manufacturing technology such as: short curing times, pumpability, printability and extrudability, buildability (the resistance of deposited wet material to deformation under loads), durability, ductility, vapour imperviousness, high tensile and compressive strength, low coefficient of thermal expansion, and resistance to UV light [4,8,9].…”

“…• reinforcement with inorganic fibres, such as short glass fibres [17] and plastic fibres: PP, PVA and PBO [12,18]; • reinforcement with natural fibres, i.e. flax [6,7]. The main aim of this article is the investigation of the influence of material microstructure on the mechanical properties of the two kinds of composites (flax reinforced and carbon reinforced) and the comparison of two methods of production for geopolymer composites (casting and 3D printing).…”

Impact of Flax Fiber Reinforcement on Mechanical Properties of Solid and Foamed Geopolymer Concrete

“…The research results pointed out that mechanical properties are improved by fiber addition, especially flexural strength [17,23]. The other research shows the possibility of using the geopolymers reinforced by short flax fibers in additive manufacturing technology [24][25][26].…”