Mechanical behavior of a novel precast beam-to-column connection with U-shaped bars and engineered cementitious composites

2018 ◽  
Vol 21 (13) ◽  
pp. 1963-1976 ◽  
Author(s):  
Bingqing Dong ◽  
Cong Lu ◽  
Jinlong Pan ◽  
Qifeng Shan ◽  
Wanyun Yin
Keyword(s):  
Energy Dissipation ◽  
Experimental Program ◽  
Cementitious Composites ◽  
Cementitious Composite ◽  
Engineered Cementitious Composites ◽  
Seismic Region ◽  
Engineered Cementitious Composite ◽  
Flexural Failure ◽  
Bonding Performance ◽  
Precast Column

This article investigates a novel precast connection, with U-shaped bars extending from precast column to connect with the longitudinal bars in precast beams. To improve the seismic behavior of the connection, engineered cementitious composites, one kind of highly ductile concrete, were introduced into the core area of the connection, which also act as the cast-in-place material in the beam top and end. Prior to the test, finite element modeling was conducted to determine the proper splice length between U-shaped bars and beam reinforcements and also to evaluate the bonding performance of the proposed connection. The experimental program was then carried out on a monolithic connection, a precast connection with normal concrete as well as a precast connection with engineered cementitious composite, after which the seismic behaviors of the connections including their failure mode, hysteresis characteristic, stiffness degradation, ductility, and energy dissipation were analyzed. All three types of connections underwent typical flexural failure where the joint area remained intact. The negative carrying capacity, ductility, and energy dissipation were slightly lower for the connection with concrete, while the connection with engineered cementitious composite exhibited satisfactory behavior comparable to monolithic specimens. The latter connection with engineered cementitious composite is therefore suggested to be applied in highly seismic region.

Compressive behavior of steel spiral confined engineered cementitious composites in circular columns

2020 ◽  
Vol 23 (14) ◽  
pp. 3075-3088
Author(s):  
Wei Hou ◽  
Guan Lin ◽  
Xiaomeng Li ◽  
Pandeng Zheng ◽  
Zixiong Guo
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Uniaxial Tensile ◽  
Cementitious Composites ◽  
Test Results ◽  
Cementitious Composite ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Engineered Cementitious Composites ◽  
Engineered Cementitious Composite

Extensive research has been conducted on the uniaxial tensile and compressive behavior of engineered cementitious composites. Despite the high tensile ductility and high toughness of engineered cementitious composites, transverse steel reinforcement is still necessary for high-performance structural members made of engineered cementitious composites. However, very limited research has been concerned with the compressive behavior of steel-confined engineered cementitious composites. This article presents the results of axial compression tests on a series of circular engineered cementitious composite columns confined with steel spirals. The test variables included the engineered cementitious composite compressive strength, the spiral pitch, and the spiral yield stress. The test results show that steel-confined engineered cementitious composites in the test columns exhibited a very ductile behavior; the steel spiral confinement contributed effectively to the enhancement of both strength and ductility of engineered cementitious composites. The test results were then interpreted by comparing them with the predictions from some existing models. It was found that the existing models previously developed for confined concrete failed to predict the compressive strength of steel-confined engineered cementitious composites with sufficient accuracy. New fitting equations for the compressive properties of steel-confined engineered cementitious composites were then obtained on the basis of the test results of this study as well as those from an existing study.

scholarly journals Effect of Modified Polyvinyl Alcohol Fibers on the Mechanical Behavior of Engineered Cementitious Composites

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 37 ◽  
Author(s):  
Mian Sun ◽  
Youzhi Chen ◽  
Jiaoqun Zhu ◽  
Tao Sun ◽  
Zhonghe Shui ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Polyvinyl Alcohol ◽  
Performance Improvement ◽  
Fracture Resistance ◽  
Cementitious Composites ◽  
Cementitious Composite ◽  
Engineered Cementitious Composites ◽  
Engineered Cementitious Composite ◽  
Pressure Resistance ◽  
Pva Fiber

：Polyvinyl alcohol (PVA) fiber was proposed to enhance the mechanical performance of engineered cementitious composite in this research. A mixture of engineered cementitious composite with better expected performance was made by adding 2% PVA fiber. Mechanics tests, including pressure resistance, fracture resistance, and ultimate tensile strength, were conducted. They reveal that the engineered cementitious composites not only exhibit good pressure resistance, but they also exhibit excellent fracture resistance and strain capability against tensile stress through mechanics tests, including pressure resistance, fracture resistance, and ultimate tensile resistance. To further improve the engineered composites’ ductility, attempts to modify the performance of the PVA fiber surface have been made by using a vinyl acetate (VAE) emulsion, a butadiene–styrene emulsion, and boric anhydride. Results indicated that the VAE emulsion achieved the best performance improvement. Its use in fiber pre-processing enables the formation of a layer of film with weak acidity, which restrains the hydration of adjacent gel materials, and reduces the strength of transitional areas of the fiber/composite interface, which restricts fiber slippage and pulls out as a result of its growth in age, and reduces hydration levels. Research illustrates that the performance-improvement processing that is studied not only improves the strain of the engineered cementitious composites, but can also reduce the attenuation of the strain against tensile stress.

scholarly journals Effect of Fibre Types on the Tensile Behaviour of Engineered Cementitious Composites

2021 ◽  
Vol 8 ◽  
Author(s):  
Mingzhang Lan ◽  
Jian Zhou ◽  
Mingfeng Xu
Keyword(s):  
Mechanical Properties ◽  
Experimental Result ◽  
Tensile Behaviour ◽  
Cementitious Composites ◽  
Matrix Interface ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite ◽  
Fibre Bridging ◽  
The Difference ◽  
Fibre Matrix

Engineered cementitious composite (ECC) is a group of ultra-ductile fibre-reinforced cementitious composites, characterised by high ductility and moderate content of short discontinuous fibre. The unique tensile strain-hardening behaviour of ECC results from a deliberate design based on the understanding of micromechanics between fibre, matrix, and fibre–matrix interface. To investigate the effect of fibre properties on the tensile behaviour of ECCs is, therefore, the key to understanding the composite mechanical behaviour of ECCs. This paper presents a study on the fibre-bridging behaviour and composite mechanical properties of ECCs with three types of fibres, including oil-coated polyvinyl alcohol (PVA) fibre, untreated PVA fibre, and polypropylene (PP) fibre. The experimental result reveals that various fibres with different properties result in difference in the fibre-bridging behaviour and composite mechanical properties of ECCs. The difference in the composite mechanical properties of ECCs with different fibres was interpreted by analysing the fibre-bridging behaviour.

Evaluation of reinforced concrete and reinforced engineered cementitious composite (ECC) members and structures using small-scale testing

2015 ◽  
Vol 42 (3) ◽  
pp. 164-177 ◽  
Author(s):  
Bora Gencturk ◽  
Farshid Hosseini
Keyword(s):  
Reinforced Concrete ◽  
Energy Absorption ◽  
High Energy ◽  
Absorption Capacity ◽  
System Level ◽  
Experimental Program ◽  
Small Scale ◽  
Cementitious Composite ◽  
Energy Absorption Capacity ◽  
Engineered Cementitious Composite

The behavior of reinforced concrete (RC) and reinforced engineered cementitious composites (ECC) was comparatively investigated at the component and system levels through a small-scale (1/8 scale factor) experimental program. The logistical and financial advantages of small-scale testing were utilized to investigate a range of parameters, including the effect of reinforcement ratio and material properties, on the response of reinforced concrete and reinforced ECC structures. The procedures pertaining to material preparation, specimen construction, and input motion development that were critical for enhancing the similarity between the scales are provided. Engineered cementitious composite mixtures with different cost and sustainability indices were evaluated. Under cyclic loading, the stiffness, strength, ductility, and energy absorption capacity of columns made of different ECC mixtures were found to be 110, 65, 45, and 100% higher, respectively, than those of the RC columns. The system level investigation through hybrid simulation showed that the ECC structures sustain less deformation under earthquake excitation due to high energy absorption capacity of the material. The differences in cost, sustainability, and structural performance of different ECC mixtures suggest that a careful selection of materials is required for optimal performance.

The mechanical properties of engineered cementitious composites containing limestone powder replaced by microsilica sand

2013 ◽  
Vol 40 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Kazim Turk ◽  
Serhat Demirhan
Keyword(s):  
Mechanical Properties ◽  
Silica Sand ◽  
Limestone Powder ◽  
Experimental Program ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite ◽  
Four Levels ◽  
Positive Effect ◽  
Composite Properties ◽  
Reference Mixture

In this study, an experimental program is conducted to understand the effect of the limestone powder (LSP) content replaced by silica sand on the composite properties. For this purpose, five different engineered cementitious composite (ECC) mixtures were adopted: ECC mixture with only silica sand (SS) for control purposes and four ECC mixtures in which SS is partially replaced by four levels of replacements (25%, 50%, 75%, and 100% by weight of total SS) of LSP. The properties of ECC mixtures produced were investigated for the ages of 3, 28, and 90 days. It was concluded that the mechanical properties of the ECC mixtures with LSP were in general higher than the reference mixture with only SS for all curing ages. Increase in the LSP content had a positive effect on the performance of the compressive strength, fracture toughness, and flexural strength at the ages of 3 and 28 days while this was not valid at the age of 90 days when compared to the reference mixture. Also, the ductility of the ECC beams strongly depends on the LSP content and specimen age.

scholarly journals Strengthening of RC Structures by Using Engineered Cementitious Composites: A Review

2019 ◽  
Vol 11 (12) ◽  
pp. 3384 ◽  
Author(s):  
Xing-yan Shang ◽  
Jiang-tao Yu ◽  
Ling-zhi Li ◽  
Zhou-dao Lu
Keyword(s):  
Tensile Strain ◽  
Building Structures ◽  
Cementitious Composite ◽  
Multiple Cracking ◽  
Rc Structures ◽  
Engineered Cementitious Composite ◽  
Bonding Performance ◽  
Steel Bars ◽  
Extensive Collection ◽  
Strong Interfacial Bonding

This paper presents a review of the recent work assessing the performance of building structures strengthened with engineered cementitious composite (ECC). ECC characterizes tensile strain hardening and multiple cracking properties, as well as strong interfacial bonding performance with substrate concrete, which makes it a promising retrofitting material. A lot of researches have been conducted on reinforced concrete (RC) structures, including beams, columns, beam–column joints, and fire-damaged slabs, strengthened with ECC material, and an extensive collection of valuable conclusions were obtained. These strengthening systems usually combine ECC with FRP textiles or steel bars to form a composite strengthening layer. The review demonstrates that ECC strengthening can greatly improve the performance of RC structures.

scholarly journals Experimental Investigation on Dynamic Tensile Behaviors of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7042
Author(s):  
Liang Li ◽  
Hongwei Wang ◽  
Jun Wu ◽  
Shutao Li ◽  
Wenjie Wu
Keyword(s):  
Energy Dissipation ◽  
Strain Rate ◽  
Peak Stress ◽  
Cementitious Composites ◽  
Failure Behavior ◽  
Engineered Cementitious Composites ◽  
Volume Fractions ◽  
Kevlar Fiber ◽  
The Matrix ◽  
Pva Fiber

Engineered cementitious composites (ECC) used as runway pavement material may suffer different strain rate loads such as aircraft taxiing, earthquakes, crash impacts, or blasts. In this paper, the dynamic tensile behaviors of the steel grid-polyvinyl alcohol (PVA) fiber and KEVLAR fiber-reinforced ECC were investigated by dynamic tensile tests at medium strain rates. The mixture was designed with different volume fractions of fibers and layer numbers of steel grids to explore the reinforcement effectiveness on the dynamic performance of the ECC. The volume fractions of these two types of fibers were 0%, 0.5%, 1%, 1.5%, and 2% of the ECC matrix, respectively. The layer numbers of the steel grid were 0, 1, and 2. The dynamic tensile behaviors of the PVA fiber and the KEVLAR fiber-reinforced ECC were also compared. The experimental results indicate that under dynamic tensile loads, the PVA-ECC reveals a ductile and multi-cracking failure behavior, and the KEVLAR-ECC displays a brittle failure behavior. The addition of the PVA fiber and the KEVLAR fiber can improve the tensile peak stress of the ECC matrix. For the specimens A0.5, A1, A1.5, and A2.0, the peak stress increases by 84.3%, 149.4%, 209.6%, and 237.3%, respectively, compared to the matrix specimen. For the specimens K0.5, K1, K1.5, and K2, the peak stress increases by about 72.3%, 147.0%, 195.2%, and 263.9%, respectively, compared to the matrix specimen. The optimum fiber volume content is 1.5% for the PVA-ECC and the KEVLAR-ECC. The KEVLAR-ECC can supply a higher tensile strength than the PVA-ECC, but the PVA-ECC reveals more prominent deformation capacity and energy dissipation performance than the KEVLAR-ECC. Embedding steel grid can improve the tensile peak stress and the energy dissipation of the ECC matrix. For the strain rate of 10−3 s−1, the peak stress of the A0.5S1 and A0.5S2 specimens increases by about 49.1% and 105.7% compared to the A0.5 specimen, and the peak stress of the K0.5S1 and K0.5S2 specimens increases by about 61.5% and 95.8%, respectively, compared to the K0.5 specimen.

Sign in / Sign up

Export Citation Format

Share Document