Structural Characterization of Several Cement-Based Materials Containing Chemical Additives with Potential Application in Additive Manufacturing

Abstract

The rapid increase in additive manufacturing applications in all industries has highlighted the lack of innovative technologies and processes in the construction industry. Several European and international policies are in place to guide the development of the technological processes involved in the construction industry toward a sustainable future. Considering the global concerns regarding this industry, the purpose of this study was to develop new cement-based materials that are capable of accelerated hydration and early strength development for use in additive manufacturing. Ca(NO3)2·4H2O, Al2(SO4)3·18H2O and Na2S2O3·5H2O were used to obtain the accelerating effect in the hydration of Portland cement. Based on results obtained from X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX) techniques, as well as low-field nuclear magnetic resonance relaxometry (LF-NMR) techniques, it was demonstrated that all accelerators used have a quickening effect on cement hydration. The addition of Na2S2O3·5H2O or combined Na2S2O3·5H2O and Ca(NO3)2·4H2O led to obtaining new cement-based materials with early strength development and fast hydration of microorganized internal structures, critical characteristics for 3D printing.

Preserving Tradition through Evolution: Critical Review of 3D Printing for Saudi Arabia’s Cultural Identity

“…This ground-breaking technique, known as Stereolithography or "SLA", involves building up layers of photopolymer material and solidifying it using a UV laser. Recognizing its potential, Hull founded 3D Systems to advance this technology further [18,19]. In 1992, Hull's 3D Systems company produced the SLA-1, the world's first commercial Stereolithography Apparatus (SLA).…”

Potential Role of GGBS and ACBFS Blast Furnace Slag at 90 Days for Application in Rigid Concrete Pavements

“…The images of the mortar samples M I, M II/360, and M III/330 aged 90 days (Figure 6) show that their surfaces are irregular and inhomogeneous with pore-like defects. Since the SEM technique is better suited for the study of macropores (pores > 50 nm) [85] and is limited due to the properties of the material studied, the defects observed were in the category of air voids (>several µm) [86][87][88]. Some authors use methods such as mercury intrusion porosimetry (MIP) and fractal dimensions [89][90][91] for a more complex characterization of the pore structure, but the SEM technique was used for this work, as it provides additional information about the surface structure.…”