scholarly journals Mechanical Behavior of Printed Strain Hardening Cementitious Composites

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2253
Author(s):  
Stefan Chaves Figueiredo ◽  
Claudia Romero Rodríguez ◽  
Zeeshan Y. Ahmed ◽  
Derk H. Bos ◽  
Yading Xu ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Cementitious Composites ◽  
Multiple Cracks ◽  
Micro Computed Tomography ◽  
Engineering Strain ◽  
Strain Hardening Behavior

Extrusion based additive manufacturing of cementitious materials has demonstrated strong potential to become widely used in the construction industry. However, the use of this technique in practice is conditioned by a feasible solution to implement reinforcement in such automated process. One of the most successful ductile materials in civil engineering, strain hardening cementitious composites (SHCC) have a high potential to be employed for three-dimensional printing. The match between the tailored brittle matrix and ductility of the fibres enables these composites to develop multiple cracks when loaded under tension. Using previously developed mixtures, this study investigates the physical and mechanical performance of printed SHCC. The anisotropic behavior of the materials is explored by means of mechanical tests in several directions and micro computed tomography tests. The results demonstrated a composite showing strain hardening behavior in two directions explained by the fibre orientation found in the printed elements. Moreover, the printing technique used also has guaranteed an enhanced bond in between the printed layers.

scholarly journals An Overview on the Rheology, Mechanical Properties, Durability, 3D Printing, and Microstructural Performance of Nanomaterials in Cementitious Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2950
Author(s):  
Hongwei Song ◽  
Xinle Li
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Research Area ◽  
Cementitious Composites ◽  
Split Tensile Strength ◽  
Contour Crafting ◽  
Wide Range ◽  
Active Research

The most active research area is nanotechnology in cementitious composites, which has a wide range of applications and has achieved popularity over the last three decades. Nanoparticles (NPs) have emerged as possible materials to be used in the field of civil engineering. Previous research has concentrated on evaluating the effect of different NPs in cementitious materials to alter material characteristics. In order to provide a broad understanding of how nanomaterials (NMs) can be used, this paper critically evaluates previous research on the influence of rheology, mechanical properties, durability, 3D printing, and microstructural performance on cementitious materials. The flow properties of fresh cementitious composites can be measured using rheology and slump. Mechanical properties such as compressive, flexural, and split tensile strength reveal hardened properties. The necessary tests for determining a NM’s durability in concrete are shrinkage, pore structure and porosity, and permeability. The advent of modern 3D printing technologies is suitable for structural printing, such as contour crafting and binder jetting. Three-dimensional (3D) printing has opened up new avenues for the building and construction industry to become more digital. Regardless of the material science, a range of problems must be tackled, including developing smart cementitious composites suitable for 3D structural printing. According to the scanning electron microscopy results, the addition of NMs to cementitious materials results in a denser and improved microstructure with more hydration products. This paper provides valuable information and details about the rheology, mechanical properties, durability, 3D printing, and microstructural performance of cementitious materials with NMs and encourages further research.

Mechanical Properties of AlSi12-Based Metal Matrix Composites with Layered Metallic Glass Ribbons

2017 ◽  
Vol 742 ◽  
pp. 181-188
Author(s):  
Klaudia Lichtenberg ◽  
Kay André Weidenmann
Keyword(s):  
Metallic Glass ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Matrix Composites ◽  
Micro Computed Tomography ◽  
Pressure Infiltration ◽  
Four Point Bending ◽  
Novel Approach ◽  
Lightweight Alloys

During the last years, several studies proved the high potential of metallic glasses to be used as reinforcements in lightweight alloys. Thereby, focus was mostly on particle reinforced composites or three-dimensional and omnidirectional glass arrays within the composite. Using a specific layered structure of the entire ribbons as reinforcement to design direction-dependent tailored properties is a novel approach. The composites in this study were produced by gas pressure infiltration of a layered stack of metallic glass ribbons. Ribbons of the metallic glass Ni60Nb20Ta20 were used as reinforcements and aluminum alloy AlSi12 as matrix. Mechanical tests like four point bending and tensile tests as well as elastic analysis using ultrasound phase spectroscopy (UPS) were performed to classify composite’s properties. Further, micro computed tomography (µCT) analysis and metallographic investigations were carried out on the four point bending samples after testing to reveal occurring damage mechanisms.

Effects of Processing on Fiber Distribution and Mechanical Performance of Engineered Cementitious Composites (ECC)

2013 ◽  
Vol 709 ◽  
pp. 122-126
Author(s):  
Heng Mao Niu ◽  
Yong Ming Xing ◽  
Yan Ru Zhao
Keyword(s):  
Strain Hardening ◽  
Crack Width ◽  
Mechanical Performance ◽  
Processing Technique ◽  
Cementitious Composites ◽  
Fiber Distribution ◽  
Engineered Cementitious Composites ◽  
Research Results

Engineered cementitious composites (ECC) are characterized by strain hardening and tight crack width control. Good fiber distribution can maximize fiber contribution. Processing can substantially influence fiber distribution, and consequently influence mechanical performance. Combined with the latest research results, this review summarizes the results of several studies in which the influence of processing on fiber distribution and mechanical performance was investigated. Based on the reviewed methods it is argued that the processing technique of producing ECC can improve fiber distribution.

scholarly journals Microstructural Characterization of 3D Printed Cementitious Materials

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2993 ◽  
Author(s):  
Jolien Van Der Putten ◽  
Maxim Deprez ◽  
Veerle Cnudde ◽  
Geert De Schutter ◽  
Kim Van Tittelboom
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Microstructural Characterization ◽  
Lower Surface ◽  
Cementitious Materials ◽  
Lower Amount ◽  
Time Interval ◽  
3D Printed ◽  
Printing Speed

Three-dimensional concrete printing (3DCP) has progressed rapidly in recent years. With the aim to realize both buildings and civil works without using any molding, not only has the need for reliable mechanical properties of printed concrete grown, but also the need for more durable and environmentally friendly materials. As a consequence of super positioning cementitious layers, voids are created which can negatively affect durability. This paper presents the results of an experimental study on the relationship between 3DCP process parameters and the formed microstructure. The effect of two different process parameters (printing speed and inter-layer time) on the microstructure was established for fresh and hardened states, and the results were correlated with mechanical performance. In the case of a higher printing speed, a lower surface roughness was created due to the higher kinetic energy of the sand particles and the higher force applied. Microstructural investigations revealed that the amount of unhydrated cement particles was higher in the case of a lower inter-layer interval (i.e., 10 min). This phenomenon could be related to the higher water demand of the printed layer in order to rebuild the early Calcium-Silicate-Hydrate (CSH) bridges and the lower amount of water available for further hydration. The number of pores and the pore distribution were also more pronounced in the case of lower time intervals. Increasing the inter-layer time interval or the printing speed both lowered the mechanical performance of the printed specimens. This study emphasizes that individual process parameters will affect not only the structural behavior of the material, but they will also affect the durability and consequently the resistance against aggressive chemical substances.

scholarly journals Structural Performance and Reinforcement Improvement of Structural Walls Using Strain-Hardening Cementitious Composites

2021 ◽  
Vol 13 (7) ◽  
pp. 3607
Author(s):  
Hyeong-Ki Kim ◽  
Chang-Geun Cho ◽  
Sun-Ju Lee ◽  
Young Hak Lee ◽  
Taehoon Kim
Keyword(s):  
Strain Hardening ◽  
Shear Walls ◽  
Mechanical Tests ◽  
Structural Performance ◽  
Cementitious Composites ◽  
Structural Walls ◽  
Damage And Failure ◽  
Load Carrying ◽  
Loading Tests ◽  
Rc Shear Wall

Reinforced concrete (RC) shear walls are effective in improving lateral stiffness and load-carrying capacity under earthquake and wind loads. According to the level of seismic design, however, the spacing of reinforcing steel bars should be very narrow and complicated, with tight spacing of tied bars, as is the case with seismically special RC shear wall design. The purpose of this study was to investigate the applicability of strain-hardening cementitious composites (SHCCs) in structural walls in order to improve structural performance as well as the complications with reinforcement details. The SHCC was mixed, and mechanical tests showed that the SHCC exhibited high ductile tensile strains above 2.0%, while sustaining the tensile stress after cracks and developing multiple microcracks, avoiding crack localizations. Six specimens of RC and reinforced SHCC structural walls were designed and manufactured with varying reinforcement details, and experiments on wall specimens were carried out under transverse wall-loading tests. These experiments demonstrated that the use of SHCC in structural walls, despite minimum use of reinforcement ratios, showed improved responses to minimize damage and failure caused by localized cracks under bending and shear to compared with the use of normal reinforcement ratios in RC walls.

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