Effect of drying environment on mechanical properties, internal RH and pore structure of 3D printed concrete

Ma, Lei; Zhang, Qing; Jia, Zijian; Liu, Chao; Deng, Zhicong; Zhang, Yamei

doi:10.1016/j.conbuildmat.2021.125731

Cited by 40 publications

(14 citation statements)

References 47 publications

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“…As shown in Figure 17 , the pores in the casted samples exhibit circular shapes, while the pores in the 3DPC samples mostly exhibit irregular shapes (approximately ellipsoidal shapes). It agrees with some findings from other researchers regarding the pore shape observation based on 2D images [ 20 , 28 ]. Meanwhile, the size of pores with a good representativeness are marked in Figure 17 .…”

Section: X-ct Results Analysissupporting

confidence: 93%

“…Owing to this significance, the research interest on layer-to-layer interfaces of 3DPC is growing [ 6 , 7 , 8 ]. The research is mainly focused on two aspects: (1) enhancing the bond strength between layers [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]; (2) anisotropy in mechanical properties resulting from layer-to-layer interfaces [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Apart from the two aspects, several researchers also studied how printing process parameters, e.g., depositing height, layers time intervals [ 24 , 25 , 26 , 27 ], influence the bonding strength between interfaces.…”

Section: Introductionmentioning

confidence: 99%

“…So far, however, there is less information about the specific definition of the printing layered interfaces, and there has been very little discussion about the characteristics of the interfaces. For instance, with respect to the number of interfaces, most of the research only showed several layers in the 3D CT rendering, which was limited to four layers (three interfaces) [ 20 , 25 , 28 ]. Xin Huang et al have presented five interlayers in 3D CT reconstruction [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Internal Structure of Hardened 3D-Printed Concrete by X-CT Scanning and Its Influence on the Mechanical Performance

et al. 2023

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As we know, 3DPC is printed layer by layer compared with mold-casting conventional concrete. Pore structure and layer-to-layer interface are two main aspects of the internal structure for 3DPC, which decide 3DPC’s mechanical performance. The layer-to-layer interface caused by printing is specific to 3DPC. The emphasis of this study lies in the layer-to-layer interfaces of 3DPC. The first aim of this study is to quantify the characteristics of the layer-to-layer interface and therefore characterize different aspects of the interfaces. The second aim of this study is to explore how the internal structure of printed concrete influences the mechanical performance of 3DPC. This research set out to design a series of experimental comparisons between 3DPC and casted concrete with the same compositions. Mechanical tests, i.e., compressive stress, ultrasonic Pulse Velocity test, flexural tension, and tension splitting, as well as the Ultrasonic Pulse Velocity test, were performed to check the mechanical performance of 3DPC. Contrary to what has often been expected, the mechanical test results showed the printed concrete has a quality not worse than casted concrete with the same recipe. Meanwhile, the X-ray computed tomography (X-CT) is used to characterize the internal structure, pore shapes, and interfaces of 3DPC. First, the investigation revealed that the lower total porosity and fewer big voids could be the fundamental causes meaning 3DPC has a better mechanical performance than casted concrete. Second, the statistics based on aspect ratio show that the distribution curves follow similar trends, regardless of the printed or casted concrete. Third, this study quantified the depth of the different interfaces for 3DPC. The results suggest that the porosity in an interface varies in a range. The author’s pioneer work has contributed to our present understanding of the interfaces of 3DPC.

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Section: X-ct Results Analysissupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Internal Structure of Hardened 3D-Printed Concrete by X-CT Scanning and Its Influence on the Mechanical Performance

et al. 2023

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“…However, in a study by El Inaty et al, 104 it was determined that 3DPC specimens showed good resistance to 0.5% sulfuric acid attack for 84 days, and strength and mass loss increased rapidly in the following days. It was reported that these differences in acid resistance are due to (i) the concrete mixtures become denser during extrusion and chemical diffusion becomes more difficult, and (ii) the deterioration increases due to the large and long pores caused by the printing process after the sulfuric acid reaches the pores 72 . In a study by Malan et al, 109 the effect of interlayer interval time variation on the carbonation resistance of 3DPC mixtures was investigated and compared with conventional concrete mixtures.…”

Section: Assessment Of Strength and Durability Performance Of 3dpc Mi...mentioning

confidence: 99%

Mechanical properties, durability performance and interlayer adhesion of 3DPC mixtures: A state‐of‐the‐art review

Şahin

Mardani‐Aghabaglou

2023

Structural Concrete

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In this study, the strength and durability performance of 3D printing concrete mixtures (3DPC) were examined in terms of the materials used in their production and printing process parameters (interlayer interval time, printing speed, and nozzle shape). Due to the anisotropic nature of 3DPC, it was understood that the compressive strength depends on the loading direction. It was emphasized that it is necessary to control the shrinkage behavior of 3DPC mixtures due to the lack of formwork and the high dosage of binders. It was reported that the interlayer adhesion of 3DPC is highly dependent on the interlayer interval time and printing speed parameters. It was understood that nozzle shape and standoff distance affect the mechanical properties and surface roughness of 3DPC specimens, and this effect is more pronounced in mixtures with high static yield stress values.

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“…Nowadays, AM is increasingly used in mass fabrication [ 25 , 26 ]. It offers original equipment manufacturers in various parts of the industry the opportunity to create a distinctive profile based on new customer benefits, cost-effective potential, and the ability to meet sustainability goals [ 27 , 28 ]. This process has many benefits, such as a simple supply chain, longevity of products, and a simple assembly chain.…”

Section: Introductionmentioning

confidence: 99%

Energy-Consumption-Based Life Cycle Assessment of Additive-Manufactured Product with Different Types of Materials

Ülkir

2023

Polymers

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Additive manufacturing (AM) or 3D printing technology is one of the preferred methods to ensure sustainability in fabrication. In addition to providing continuity in sustainability, fabrication, and diversity, it aims to improve people’s quality of life, develop the economy, and protect the environment and resources for future generations. In this study, the life cycle assessment (LCA) method was used to determine whether a product fabricated by the AM provides tangible benefits compared to traditional fabrication methodologies. LCA is an evaluation method that provides information on resource efficiency and waste generation, where the environmental impacts of a process can be calculated, measured, and reported throughout the entire life cycle, starting from the acquisition of raw materials, processing, fabrication, use, end of life, and disposal, according to ISO 14040/44 standards. This study examines the environmental impacts of the three most preferred filaments and resin materials in the AM for a 3D-printed product from the start, which consists of three stages. These stages are raw material extraction, manufacturing, and recycling. Filament material types are Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), Polyethylene Terephthalate (PETG), and Ultraviolet (UV) Resin. The fabrication process was carried out with Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques using a 3D printer. Environmental impacts for all identified steps were estimated over the life cycle using the energy consumption model. As a result of the LCA, it was seen that UV Resin was the most environmentally friendly material in the mid-point and end-point indicators. It has been determined that the ABS material also exhibits bad results on many indicators and is the least environmentally friendly. The results support those working with AM in comparing different materials’ environmental impacts and choosing an environmentally friendly material.

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Effect of drying environment on mechanical properties, internal RH and pore structure of 3D printed concrete

Cited by 40 publications

References 47 publications

Investigation of the Internal Structure of Hardened 3D-Printed Concrete by X-CT Scanning and Its Influence on the Mechanical Performance

Investigation of the Internal Structure of Hardened 3D-Printed Concrete by X-CT Scanning and Its Influence on the Mechanical Performance

Mechanical properties, durability performance and interlayer adhesion of 3DPC mixtures: A state‐of‐the‐art review

Energy-Consumption-Based Life Cycle Assessment of Additive-Manufactured Product with Different Types of Materials

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