Hybrid Materials Based on Fly Ash, Metakaolin, and Cement for 3D Printing

Abstract

Nowadays, one very dynamic development of 3D printing technology is required in the construction industry. However, the full implementation of this technology requires the optimization of the entire process, starting from the design of printing ideas, and ending with the development and implementation of new materials. The article presents, for the first time, the development of hybrid materials based on a geopolymer or ordinary Portland cement matrix that can be used for various 3D concrete-printing methods. Raw materials used in the research were defined by particle size distribution, specific surface area, morphology by scanning electron microscopy, X-ray diffraction, thermal analysis, radioactivity tests, X-ray fluorescence, Fourier transform infrared spectroscopy and leaching. The geopolymers, concrete, and hybrid samples were described according to compressive strength, flexural strength, and abrasion resistance. The study also evaluates the influence of the liquid-to-solid ratio on the properties of geopolymers, based on fly ash (FA) and metakaolin (MK). Printing tests of the analyzed mixtures were also carried out and their suitability for various applications related to 3D printing technology was assessed. Geopolymers and hybrids based on a geopolymer matrix with the addition of 5% cement resulted in the final materials behaving similarly to a non-Newtonian fluid. Without additional treatments, this type of material can be successfully used to fill the molds. The hybrid materials based on cement with a 5% addition of geopolymer, based on both FA and MK, enabled precise detail printing.

Properties of 3D Printed Concrete–Geopolymer Hybrids Reinforced with Aramid Roving

“…A single filament in the aramid roving had a diameter of 10 µm. The characteristics of the raw materials used for the research were presented in our previous work [ 29 ].…”

“…Further, fly ash and slag, due to their properties being similar to cement, are also suitable alternatives to its partial replacement [ 22 , 23 ]. Fine fly ash has pozzolanic activity [ 24 ] and can improve the compressive strength of the final product [ 25 , 26 , 27 , 28 , 29 ]. Muthusamy et al [ 27 ] showed that concrete, in which 30% of the cement was replaced with fly ash, can be used in the construction industry.…”

“…In our work, we produced concrete–geopolymer hybrids by preparing concrete and the geopolymer separately, and then by mixing them in appropriate proportions. We produced the hybrids using two methods: casting into molds and 3D printing [ 29 , 30 ]. The aim of this work was to obtain 3D printed concrete–geopolymer hybrids reinforced with aramid roving.…”

Influence of elevated temperatures on the mechanical properties of foamed geopolymer materials

“…Geopolymers are concrete-like materials, they can be cast into molds taking the shape of a vessel, they can be a binder or they can be printed with the use of additive technologies [4][5][6][7]. Geopolymers are called alkaline activated materials (due to the first phase of geopolymer formation), they are created by combining aluminosilicate materials with alkaline compounds, strongly basic sodium, potassium or acid phosphates [1,[8][9][10][11].…”

Properties of 3D-Printed Polymer Fiber-Reinforced Mortars: A Review

“…For more than a decade, the researches and applications of polymers as 3D-printed building mortar materials have attracted more and more attention from scientists. As green building materials, geopolymers can replace cement-based materials as 3D-printed building mortars in the future [ 27 , 28 , 29 ]. In this paper, the properties of the polymer fiber-reinforced 3D-printed building mortars used in recent years are summarized.…”