scholarly journals Method of Optimisation for Ambient Temperature Cured Sustainable Geopolymers for 3D Printing Construction Applications

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 902 ◽  
Author(s):  
Shin Bong ◽  
Behzad Nematollahi ◽  
Ali Nazari ◽  
Ming Xia ◽  
Jay Sanjayan
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Ambient Temperature ◽  
Shear Failure ◽  
Mechanical Performance ◽  
Silicate Solution ◽  
Ambient Temperatures ◽  
Tension Tests ◽  
Shape Retention ◽  
Interlayer Bond

Since the initial introduction of geopolymers, these materials have been characterised as environmentally-friendly sustainable substitutes for ordinary Portland cement (OPC). There is a routine increase in the application of geopolymers, especially in advanced technologies. Because of its better rheological characteristics compared to OPC, geopolymers are appropriate materials for extrusion-based 3D printing technologies. This paper focuses on the optimisation of an ambient temperature cured geopolymer for 3D printing construction applications. The effects of mixture parameters, including the type of hydroxide solution (HS), the type of silicate solution (SS) and the mass ratio of SS to HS on the workability, extrudability, shape retention ability and mechanical performance of different geopolymer mixtures were investigated. Accordingly, an optimum mixture was identified for geopolymers cured at ambient temperatures. Mechanical properties of the optimised mixture, including flexural and compressive strengths, were measured in different directions with respect to the printed layers. Further, uniaxial tension tests were also conducted on the optimised mixture to measure its interlayer bond strength. The results showed that among the activators investigated, the sodium-based activator composed of sodium hydroxide and sodium silicate solutions, with a SiO2/Na2O ratio of 3.22, was the most effective activator, providing appropriate workability and extrudability, along with reasonable strength and a high shape retention ability. The acquired mechanical properties exhibited anisotropic behaviour in different testing direction. The strength of the interlayer bond was found to be adequate to avoid interfacial shear failure.

scholarly journals Effect of Polypropylene Fibre Addition on Properties of Geopolymers Made by 3D Printing for Digital Construction

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2352 ◽  
Author(s):  
Behzad Nematollahi ◽  
Praful Vijay ◽  
Jay Sanjayan ◽  
Ali Nazari ◽  
Ming Xia ◽  
...  
Keyword(s):  
3D Printing ◽  
Bond Strength ◽  
Fibre Volume ◽  
Interface Plane ◽  
Flexural Performance ◽  
Fresh State ◽  
Hardened State ◽  
3D Printed ◽  
Shape Retention ◽  
Interlayer Bond

This paper investigates the effect of polypropylene (PP) fibres on the fresh and hardened properties of 3D-printed fibre-reinforced geopolymer mortars. Different percentages of PP fibres ranging between 0.25% and 1.00% by volume were added to an optimised geopolymer mixture. All samples showed reasonable workability and extrudability. In addition, shape-retention ability in the fresh state was investigated as a major requirement for 3D-printing. The compressive strength of the printed specimens was tested in the hardened state in three loading directions, viz. longitudinal, perpendicular, and lateral. The flexural strength of samples was also tested in the longitudinal and lateral directions. In addition, the interlayer bond strength was investigated. Fibre addition seems to influence compressive strengths positively only when the loading is perpendicular to the interface plane. This is due to the preferential fibre alignment parallel to the direction of extrusion. The addition of fibre significantly enhanced the flexural performance of the printed samples. The use of fibre dosages of 0.75 and 1.00 vol % caused deflection-hardening behaviour of the 3D-printed geopolymers and, hence, a significantly higher fracture energy in comparison to specimens without fibre or with lower fibre content. However, an increase in the fibre volume caused some minor reduction in interlayer bond strength. With respect to properties in the fresh state, higher fibre volumes caused better shape-retention ability in the printed samples. The results indicate the possibility of printing fibre-reinforced geopolymers which meet all the necessary properties in both the fresh and hardened states.

scholarly journals The Mechanical Properties of Fiber Metal Laminates Based on 3D Printed Composites

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5264
Author(s):  
Bharat Yelamanchi ◽  
Eric MacDonald ◽  
Nancy G. Gonzalez-Canche ◽  
Jose G. Carrillo ◽  
Pedro Cortes
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Velocity ◽  
Mechanical Performance ◽  
High Velocity Impact ◽  
Low Velocity ◽  
Fiber Metal Laminates ◽  
Velocity Impact ◽  
3D Printed ◽  
Fiber Metal

The production and mechanical properties of fiber metal laminates (FMLs) based on 3D printed composites have been investigated in this study. FMLs are structures constituting an alternating arrangement of metal and composite materials that are used in the aerospace sector due to their unique mechanical performance. 3D printing technology in FMLs could allow the production of structures with customized configuration and performance. A series of continuous carbon fiber reinforced composites were printed on a Markforged system and placed between layers of aluminum alloy to manufacture a novel breed of FMLs in this study. These laminates were subjected to tensile, low velocity and high velocity impact tests. The results show that the tensile strength of the FMLs falls between the strength of their constituent materials, while the low and high velocity impact performance of the FMLs is superior to those observed for the plain aluminum and the composite material. This mechanism is related to the energy absorption process displayed by the plastic deformation, and interfacial delamination within the laminates. The present work expects to provide an initial research platform for considering 3D printing in the manufacturing process of hybrid laminates.

scholarly journals Experimental Study on the Fracture Evolution Processof Rock-like Specimens Containing a Closed RoughJoint Based on 3D-Printing Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Jiawei Liu ◽  
Haijian Su ◽  
Hongwen Jing ◽  
Chengguo Hu ◽  
Qian Yin
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Failure Mode ◽  
Shear Failure ◽  
Rock Joints ◽  
Image Correlation ◽  
Printing Technology ◽  
3D Printing Technology ◽  
Joint Inclination ◽  
Joint Length

In order to overcome the disadvantage of traditional joint fabrication method—inability to reproduce the rough surfaces of practical rock joints—3D-printing technology was applied to restructure five kinds of rough joint according to the failure surface formed by the triaxial prepeak unloading test in this study. And uniaxial compression test was carried out on the rock-like specimens containing closed 3D-printing rough joint to study the effects of joint inclination and joint length on the mechanical properties (peak strength, peak strain, elastic modulus, and secant modulus), cracking process, and failure modes. Besides, digital image correlation (DIC) method and acoustic emission (AE) system are used to investigate the whole evolution process of strain fields and crack propagation during loading. It is found that the mechanical parameters decrease first and then go up as the joint inclination increases, while presenting a continuous downward trend with the increase of joint length. Inclination of 45° and the larger joint length bring more extensive reduction to mechanical properties of specimens. Specimens exhibit typical brittle failure characteristics. The failure mode of specimens affected by different joint inclination is tension-shear failure. And the joint scale rises; the failure mode of specimens changes from tensile failure to shear failure. Larger joint scale results in the longer prepeak fluctuation phase on axial stress-strain curves and more dispersed distribution of high-value AE counts.

scholarly journals Mechanical Properties of Innovative Multi-layer Composite Laminated Panels

2018 ◽  
Author(s):  
Jan Niederwestberg ◽  
Jianhui Zhou ◽  
Ying-Hei Chui
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Shear Failure ◽  
Mechanical Performance ◽  
Bottom Layer ◽  
Rolling Shear ◽  
Analogy Method ◽  
Aesthetic Appearance ◽  
Layer Composite ◽  
Dimension Lumber

Cross-laminated timber (CLT) possesses both good shape stability and the possible two-way force transfer ability due to its crosswise lamination. However, the transverse layers in CLT are prone to rolling shear failure under an out-of-plane load. An innovative multi-layer composite laminated panel (CLP) was developed by combining structural composite lumber (SCL) and dimension lumber to overcome the rolling shear failure while maintaining high mechanical performance and aesthetic appearance of natural wood. The mechanical properties of 5-layer CLP consisted of laminated strand lumber (LSL) and dimension lumber with different layups were evaluated by both static and modal tests. The results showed that the shear resistance, bending stiffness and moment resistance of CLP were up to 143%, 43% and 87% higher than their counterparts of regular CLT, respectively. The failure modes observed in both shear and bending tests indicated that the use of LSL in transverse layers could eliminate the potential rolling shear failure in CLT. With the lamination properties from components tests as inputs, the validity of shear analogy method was assessed by test results. The mechanical properties can be well predicted by shear analogy method except for the bending moment resistance of CLP and CLT with either rolling failure in the cross layer or tension failure in the bottom layer.

scholarly journals Mechanical Properties of Innovative, Multi-Layer Composite Laminated Panels

Buildings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 142 ◽  
Author(s):  
Jan Niederwestberg ◽  
Jianhui Zhou ◽  
Ying-Hei Chui
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Shear Failure ◽  
Mechanical Performance ◽  
Bottom Layer ◽  
Rolling Shear ◽  
Analogy Method ◽  
Aesthetic Appearance ◽  
Layer Composite ◽  
Dimension Lumber

Cross-laminated timber (CLT) possesses both good shape stability and possible two-way force transfer ability due to its crosswise lamination. However, the transverse layers in CLT are prone to rolling shear failure under an out-of-plane load. An innovative multi-layer composite laminated panel (CLP) was developed by combining structural composite lumber (SCL) and dimension lumber to overcome the rolling shear failure while maintaining the high mechanical performance and aesthetic appearance of natural wood. The mechanical properties of 5-layer CLP that consisted of laminated strand lumber (LSL) and dimension lumber with different layups were evaluated by both static and modal tests. The results showed that the shear resistance, bending stiffness, and moment resistance of CLP were up to 143%, 43%, and 87% higher than their counterparts of regular CLT, respectively. The failure modes observed in both shear and bending tests indicated that the use of LSL in transverse layers could eliminate the potential rolling shear failure in CLT. With the lamination properties from components tests as inputs, the validity of shear analogy method was assessed by test results. The mechanical properties can be well predicted by shear analogy method except for the bending moment resistance of CLP and CLT with either rolling failure in the cross layer or tension failure in the bottom layer.

scholarly journals Highly Mechanical Performance of Laminated Veneer Lumber Induced by High Voltage Electrostatic Field

2019 ◽  
pp. 67-75
Author(s):  
Qian He ◽  
Tianyi Zhan ◽  
Zehui Ju ◽  
Haiyang Zhang ◽  
Lu Hong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
High Voltage ◽  
Electrostatic Field ◽  
Shear Failure ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Contact Angles ◽  
Bonding Interface ◽  
Laminated Veneer Lumber

The high voltage electrostatic field (HVEF), as a novel technology, was applied in the study to obtain a highly mechanical performance of LVL (laminated veneer lumber) by increasing limiting value of shear failure strength directly affected by bonding strength. The surface property of wood, polymerization extent of PF, bonding interface of wood-to-PF and mechanical properties of LVL were investigated under the HVEF treatment. The results showed that increased free radicals and total surface energy were acquired under the HVEF treatment resulting from more polar groups (?OH, ?CHO) and ions were triggered leading to decreased contact angles identified both for Poplar and Masson specimens. The HVEF provided more reactions among wood-to-UF and more cross linking reaction of PF occurred in the treating step. The tendency of vertical density profile was more extremely steep than the control with max density increased by 24.93% and 30.24% for Poplar and Masson LVL respectively since adhesive aggregated continuously and orderly along bonding interface and permeation depth reduced to around 200 ?m, accounting for improved bonding shear strength, which eventually brought an enhancement on mechanical properties of LVL with horizon shear strength (?and?), modulus of elasticity and static bending strength significantly enhanced by 14.65%, 10.68%, 20.67% and 12.34% for Poplar LVL and that of Masson LVL enhanced by 17.30%, 13.93%, 18.55% and 12.72%. Besides, the delamination ratio was decreased by 49.57% and 58.32% respectively both for Poplar and Masson specimens.

scholarly journals Fabrication of Carbonnanotube/Polymer Nanocomposite Sheets and Its Mechanical Performance

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Mechanical Performance ◽  
Polymer Nanocomposite ◽  
Deposition Process ◽  
Tension Tests ◽  
Multi Walled Carbon Nanotube ◽  
Uniform Dispersion ◽  
Reinforcing Agent ◽  
Matrix Nanocomposites

Carbon nanocomposites have received a great deal of attention in recent years in view of their special properties such as low density, superior thermal and mechanical properties. However, poor dispersion and poor interfacial bonding limit the full utilization of carbon nanotubes as reinforcing agent in polymer nanocomposites. This paper presents an approach developed for production of polymer matrix nanocomposites with uniformly distributed multi-walled carbon nanotube (MWCNT). This approach involves preparation of a stable MWCNT in Nafion® polymer matrix followed by fabrication of MWCNT-Nafion® nanocomposite via a novel electrochemical co-deposition process (ECD). The ECD process introduced here follows the similar basic principles of traditional electrophoretic deposition. Morphology and microstructure of fabricated MWCNT-Nafion® nanocomposite sheets were evaluated through scanning electron microscopy(SEM). The mechanical performance of the nanocomposite was assessed by tension tests per ASTM D3039. Deposition of the MWCNT-Nafion® nanocomposite on an aluminum sheet produced significant gains in the tensile properties of the sheet. This finding confirms that uniform dispersion of MWCNT in a polymer matrix can produce nanocomposites with desired mechanical properties.

Mechanical Performance Analysis of ULTEM 9085 in a Heated, Irradiated Environment

2018 ◽  
Author(s):  
Matthew B. Ng ◽  
Sean N. Brennan
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Performance ◽  
Cost Effective ◽  
Radiation Environment ◽  
Inspection System ◽  
Control Group ◽  
Inspection Systems ◽  
3D Printed ◽  
Cost Efficient

This paper investigates the thermal and radiation performance of 3D-printed ULTEM materials following ASTM standard D638. ULTEM is a thermoplastic in the polyetherimide (PEI) family that is regularly used as a high-grade material for 3D printing. This material has similar properties to polyether ether ketone (PEEK), which is another thermoplastic that has strong mechanical properties at elevated temperature conditions. While PEEK has stronger mechanical properties, ULTEM is significantly more cost efficient to acquire and process via 3D printing. Also, most 3D printers are unable to utilize PEEK because of the significantly higher temperature requirements this material imposes on a 3D printer. This work is motivated by the need to rapidly deploy robotic inspection systems within a nuclear canister environment, which exposes the material to temperatures up to 170°C (340°F), and radiation levels of 270 Gy/hr (27 krad/hr), which are significantly beyond that of conventional 3D-printed parts. The design analysis was performed via an experiment consisting of three treatment groups of dogbone ULTEM test pieces. After tensile testing all of the pieces, the material properties were compared to those of the control group. These results allow manufacturers to select a more cost-effective material to build parts to operate in such a harsh high-temperature, high-radiation environment, which could include applications in both space systems and nuclear inspection robotics. Specifically, the results were used to guide the development of a robust robotic inspection system for the Nuclear Energy University Program (NEUP) by replacing complex parts with easily-fabricated 3D-printed ULTEM pieces.

scholarly journals Improvement of Interlayer Adhesion and Heat Resistance of Biodegradable Ternary Blend Composite 3D Printing

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Wattanachai Prasong ◽  
Akira Ishigami ◽  
Supaphorn Thumsorn ◽  
Takashi Kurose ◽  
Hiroshi Ito
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Heat Resistance ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Dimensional Accuracy ◽  
Shell Morphology ◽  
Poly Lactic Acid ◽  
Ternary Blend ◽  
Fused Deposition

Poly(lactic acid) (PLA) filaments have been the most used in fused deposition modeling (FDM) 3D printing. The filaments, based on PLA, are continuing to be developed to overcome brittleness, low heat resistance, and obtain superior mechanical performance in 3D printing. From our previous study, the binary blend composites from PLA and poly(butylene adipate-co-terephthalate) (PBAT) with nano talc (PLA/PBAT/nano talc) at 70/30/10 showed an improvement in toughness and printability in FDM 3D printing. Nevertheless, interlayer adhesion, anisotropic characteristics, and heat resistance have been promoted for further application in FDM 3D printing. In this study, binary and ternary blend composites from PLA/PBAT and poly(butylene succinate) (PBS) with nano talc were prepared at a ratio of PLA 70 wt. % and blending with PBAT or PBS at 30 wt. % and nano talc at 10 wt. %. The materials were compounded via a twin-screw extruder and applied to the filament using a capillary rheometer. PLA/PBAT/PBS/nano talc blend composites were printed using FDM 3D printing. Thermal analysis, viscosity, interlayer adhesion, mechanical properties, and dimensional accuracy of binary and ternary blend composite 3D prints were investigated. The incorporation of of PBS-enhanced crystallinity of the blend composite 3D prints resulted in an improvement to mechanical properties, heat resistance, and anisotropic characteristics. Flexibility of the blend composites was obtained by presentation of PBAT. It should be noted that the core–shell morphology of the ternary blend influenced the reduction of volume shrinkage, which obtained good surface roughness and dimensional accuracy in the ternary blend composite 3D printing.

scholarly journals Influence of Nano Silica Particles on Durability of Flax Fabric Reinforced Geopolymer Composites

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1459 ◽  
Author(s):  
Hasan Assaedi ◽  
Thamer Alomayri ◽  
Faiz Shaikh ◽  
It-Meng Low
Keyword(s):  
Mechanical Properties ◽  
Ambient Temperature ◽  
Mechanical Performance ◽  
Physical And Mechanical Properties ◽  
Positive Influence ◽  
Silica Particles ◽  
Natural Fibres ◽  
Nano Silica ◽  
Flax Fibres ◽  
Geopolymer Composites

The durability of natural fibres as reinforcement in geopolymer composites continues to be a matter of concern due to the alkalinity of activators of geopolymer matrices. The alkaline environment is the main reason for natural fibres degradation in cementitious matrices. This paper presents the influence of nano silica (NS) on the durability and mechanical performance of geopolymer composites that are reinforced with flax fabric (FF). The durability investigations were conducted after the storage of samples at ambient temperature for 32 weeks. The study revealed that the addition of nano silica has a positive influence on the physical and mechanical properties of these composites. The presence of NS accelerated the geopolymeric reaction and lowered the alkalinity of the system, thus reducing the degradation of flax fibres.

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