Mechanical properties of engineered cementitious composites beams fabricated by extrusion-based 3D printing

2021 ◽  
Vol 238 ◽  
pp. 112201
Author(s):  
Binrong Zhu ◽  
Jinlong Pan ◽  
Zhenxin Zhou ◽  
Jingming Cai
Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2950
Author(s):  
Hongwei Song ◽  
Xinle Li

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.


Author(s):  
Shuaiyu Wang ◽  
Hongxiu Du ◽  
Jingjing Lv ◽  
Jun Guo ◽  
Guoyang Yue ◽  
...  

Engineered cementitious composites (ECC) are a type of high-performance fiber reinforced cementitious composite. ECC has different applications in the construction field due to its inherent characteristics of high tensile strain. The main concern regarding ECC is its high cost. The content of cement is high contributing to its cost. In this research work, the cement in ECC is replaced with marble dust and its mechanical properties such as compressive strength and flexure strength have been assessed. For this purpose, both cubes and cylinders were tested at different test ages for finding the compressive strength development with time and observe the shape effect of specimens on the compressive strength of ECC mixes. Beam members were tested for finding the flexure strength of ECC mixes. Deflection gauge was also installed at the mid span on the bottom surface of the beams to find the maximum mid span deflection before failure. The compression test results of both cylinders and cubes revealed that using of marble dust has negative effect on the compressive strength of ECC. The flexure strength result showed that marble dust can be used up to some extent replacing cement will increase the flexure strength. The result of mid span deflection suggests that by incorporating marble dust in ECC, its ductility increases.


2011 ◽  
Vol 250-253 ◽  
pp. 374-378
Author(s):  
Ying Zi Yang ◽  
Yan Yao ◽  
Yu Zhu

Four-point bending test was employed to investigate the effects of gradation of sand on the mechanical properties of Engineered Cementitious Composites (ECC). The characteristics of ECC such as mid-span deflection, first cracking load, peak load and fracture toughness were obtained from the load-deflection curve. Effects of gradation of sand on fresh properties, compressive strength, flexural strength and drying shrinkage of ECC were also discussed in this paper. Test results shown that when the fineness modulus of sand in ECC was 1.0, the mid-span deflection and fracture toughness of ECC increased nearly 1.5 times and 2 times that of ECC with the sand fineness modulus of 2.97, respectively. With the sand getting finer, the more superplascitizer is needed and the crack width of ECC becomes smaller. The drying shrinkage of ECC with 2.97 and 1.0 fineness modulus of sand at 24 days was 8×10-4 and 15.6×10-4, respectively.


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