Analysis of the mechanical performance and damage mechanism for 3D printed concrete based on pore structure

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

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Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

10.21203/rs.3.rs-517727/v1 ◽

2021 ◽

Author(s):

Karolina E. Mazur ◽

Aleksandra Borucka ◽

Paulina Kaczor ◽

Szymon Gądek ◽

Stanislaw Kuciel

Keyword(s):

Elevated Temperatures ◽

Mechanical Performance ◽

Natural Fibers ◽

Crystallization Rate ◽

Mechanical Tests ◽

Hydrothermal Degradation ◽

3D Printed ◽

The Impact ◽

Different Levels ◽

Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

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EXPERIMENTAL INVESTIGATION AND SIMULATION OF 3D-PRINTED LATTICE STRUCTURES

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2019.25.0052 ◽

2019 ◽

Vol 25 ◽

pp. 52-57

Author(s):

Eva Heiml ◽

Anna Kalteis ◽

Zoltan Major

Keyword(s):

Mechanical Performance ◽

Bulk Material ◽

Deformation Behaviour ◽

Lightweight Design ◽

Thermoplastic Polyurethane ◽

Selective Laser Sintering ◽

Structural Performance ◽

Lattice Structures ◽

3D Printed ◽

Manufacturing Techniques

Lattice structures are currently of high interest, especially for lightweight design. They generally have better structural performance per weight than parts made of bulk material. With conventional manufacturing techniques they are diﬃcult to produce, but with additive manufacturing (AM) fabricationisfeasible. To better understand their behaviour under various loading conditions two lattice structures in diﬀerent conﬁgurations were observed. For each structure three diﬀerent test specimens were designed and manufactured using selective laser sintering (SLS). To investigate the mechanical performance under large deformations the specimens were made of a thermoplastic polyurethane(TPU), which shows a hyperelastic material behaviour. Beside the experimental observations also ﬁnite element analyses (FEA) were conducted to investigate the deformation behaviour in more detail.

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Use of polymer concrete for large-scale 3D printing

Rapid Prototyping Journal ◽

10.1108/rpj-12-2019-0316 ◽

2021 ◽

Vol 27 (3) ◽

pp. 465-474

Author(s):

Martin Krčma ◽

David Škaroupka ◽

Petr Vosynek ◽

Tomáš Zikmund ◽

Jozef Kaiser ◽

...

Keyword(s):

3D Printing ◽

Large Scale ◽

Mechanical Performance ◽

Construction Material ◽

Polymer Concrete ◽

Fused Deposition Modelling ◽

Cast State ◽

Content Type ◽

Fused Deposition ◽

3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

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Rheological Behavior and Microstructure Characteristics of SCC Incorporating Metakaolin and Silica Fume

Materials ◽

10.3390/ma11122576 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2576 ◽

Cited By ~ 7

Author(s):

Gang Ling ◽

Zhonghe Shui ◽

Tao Sun ◽

Xu Gao ◽

Yunyao Wang ◽

...

Keyword(s):

Pore Structure ◽

Silica Fume ◽

Mechanical Performance ◽

Free Water ◽

Hydration Product ◽

Replacement Ratio ◽

Microstructure Characteristics ◽

Beneficial Effects ◽

Slump Flow ◽

Strength And Durability

This study explores the effects of metakaolin (MK) and silica fume (SF) on rheological behaviors and microstructure of self-compacting concrete (SCC). The rheology, slump flow, V-funnel, segregation degree (SA), and compressive strength of SCC are investigated. Microstructure characteristics, including hydration product and pore structure, are also studied. The results show that adding MK and SF instead of 4%, 6% and 8% fly ash (FA) reduces flowability of SCC; this is due to the fact that the specific surface area of MK and SF is larger than FA, and the total water demand increases as a result. However, the flowability increases when replacement ratio is 2%, as the small MK and SF particles will fill in the interstitial space of mixture and more free water is released. The fluidity, slump flow, and SA decrease linearly with the increase of yield stress. The total amount of SF and MK should be no more than 6% to meet the requirement of self-compacting. Adding MK or SF to SCC results in more hydration products, less Ca(OH)2 and refinement of pore structure, leading to obvious strength and durability improvements. When the total dosage of MK and SF admixture is 6%, these beneficial effects on workability, mechanical performance, and microstructure are more significant when SF and MK are applied together.

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Effect of 3D Printed Spatial Reinforcement on Flexural Characteristics of Conventional Mortar

Materials ◽

10.3390/ma13143133 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3133

Author(s):

Jacek Katzer ◽

Tomasz Szatkiewicz

Keyword(s):

Building Materials ◽

Mechanical Performance ◽

Cement Mortar ◽

Research Effort ◽

Reinforce Concrete ◽

Strength Properties ◽

Fourth Decade ◽

3D Printed ◽

Spatial Shape ◽

Manufacturing Technologies

In their fourth decade of development, additive manufacturing technologies are slowly entering research programs dedicated to building materials. While the majority of research effort is focused on using 3D printing of concrete, the authors propose using the technology for creation of spatial plastic reinforcement. Obviously, the strength properties of a 3D printed polymer are much lower than those of steel. Nevertheless, the unconventional spatial shape of a 3D printed reinforcement can substitute for much of the lower mechanical performance of polymer. Flexural characteristics of a cement mortar prism specimen reinforced by hexagon spatial elements were tested and analyzed in this paper. The hexagonal geometric shape was chosen due to its high rigidness. It was proven that it is possible to efficiently reinforce concrete beams by spatial 3D printed polymer elements. Directions of needed research were pointed and discussed.

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3D-Printable PP/SEBS Thermoplastic Elastomeric Blends: Preparation and Properties

Polymers ◽

10.3390/polym11020347 ◽

2019 ◽

Vol 11 (2) ◽

pp. 347 ◽

Cited By ~ 18

Author(s):

Shib Banerjee ◽

Stephen Burbine ◽

Nischay Kodihalli Shivaprakash ◽

Joey Mead

Keyword(s):

3D Printing ◽

Carbon Black ◽

Computer Aided Design ◽

Fused Deposition Modeling ◽

Mechanical Performance ◽

Polymeric Materials ◽

Fused Deposition ◽

3D Printed ◽

Injection Molded ◽

Preferential Location

Currently, material extrusion 3D printing (ME3DP) based on fused deposition modeling (FDM) is considered a highly adaptable and efficient additive manufacturing technique to develop components with complex geometries using computer-aided design. While the 3D printing process for a number of thermoplastic materials using FDM technology has been well demonstrated, there still exists a significant challenge to develop new polymeric materials compatible with ME3DP. The present work reports the development of ME3DP compatible thermoplastic elastomeric (TPE) materials from polypropylene (PP) and styrene-(ethylene-butylene)-styrene (SEBS) block copolymers using a straightforward blending approach, which enables the creation of tailorable materials. Properties of the 3D printed TPEs were compared with traditional injection molded samples. The tensile strength and Young’s modulus of the 3D printed sample were lower than the injection molded samples. However, no significant differences could be found in the melt rheological properties at higher frequency ranges or in the dynamic mechanical behavior. The phase morphologies of the 3D printed and injection molded TPEs were correlated with their respective properties. Reinforcing carbon black was used to increase the mechanical performance of the 3D printed TPE, and the balancing of thermoplastic elastomeric and mechanical properties were achieved at a lower carbon black loading. The preferential location of carbon black in the blend phases was theoretically predicted from wetting parameters. This study was made in order to get an insight to the relationship between morphology and properties of the ME3DP compatible PP/SEBS blends.

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The Mechanical Properties and Chloride Resistance of Concrete Reinforced with Hybrid Polypropylene and Basalt Fibres

Materials ◽

10.3390/ma12152371 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2371 ◽

Cited By ~ 4

Author(s):

Xinyu Hu ◽

Yihong Guo ◽

Jianfu Lv ◽

Jize Mao

Keyword(s):

Pore Structure ◽

Mechanical Performance ◽

Single Fibre ◽

Fibre Volume ◽

Negative Effects ◽

Basalt Fibre ◽

Structure Characteristics ◽

Chloride Resistance ◽

Hybrid Fibre ◽

Curing Age

This paper aims to investigate the effect of the polypropylene fibre (PP) and basalt fibre (BF), singly or in hybridization, on the workability, mechanical, chloride resistance and pore structure characteristics of concrete. Sixteen mixtures consisting of PP and BF, both at volume content of 0.0, 0.1, 0.2 and 0.3%, were fabricated, and the slump, compressive, splitting tensile, flexural and charge passed were tested. The results show the hybridization of the PP and BF can improve three types of strength of concrete in comparison to their single fibre. Nevertheless, the hybridization is not always conducive, and the synergy of fibres is proposed and divided into positive and negative effects. The combination of the PP and BF both at content of 0.1% achieves the best mechanical performance, and is recommended for practical usage. Incorporating fibres reduces the chloride resistance of concrete, and the hybridization is helpless to this phenomenon; even the reduction is intensified at a highly hybrid fibre volume. However, increasing the curing age can mitigate this adverse effect caused by fibres. Furthermore, the microstructures were explored to elucidate the macro-properties of concrete in terms of interface and pore structure.

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3D-printed thermoset syntactic foams with tailorable mechanical performance

Journal of Materials Science ◽

10.1007/s10853-020-05111-6 ◽

2020 ◽

Vol 55 (33) ◽

pp. 16048-16057 ◽

Cited By ~ 1

Author(s):

Nashat Nawafleh ◽

William Wright ◽

Nader Dariavach ◽

Emrah Celik

Keyword(s):

Mechanical Performance ◽

Syntactic Foams ◽

3D Printed

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