scholarly journals High Temperature Flexural Deformation Properties of Engineered Cementitious Composites (ECC) with Hybrid Fiber Reinforcement

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Zhihui YU ◽  
Zhen YUAN ◽  
Chaofan XIA ◽  
Cong ZHANG
Keyword(s):  
High Temperature ◽  
Flexural Strength ◽  
Room Temperature ◽  
Steel Fiber ◽  
Cementitious Composites ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Temperature Exposure ◽  
Pva Fiber ◽  
Strength And Toughness

Engineered Cementitious Composites (ECC) is a class of high-performance fiber reinforced composites with ultra-ductility designed based on micromechanics, and it has been developed for increasing application in the construction industry during recent decades. The properties of ECC at room temperature have been tested and studied in depth, however, few studies focus on its performance after high temperature that is one of the worst conditions to ECC. To investigate the change tendency and mechanism for the high temperature flexural properties of hybrid fiber reinforced ECC and the feasibility of calcium carbonate whisker to reduce the cost of ECC materials, polyvinyl alcohol fiber (PVA) reinforced strain hardening cementitious composites (PVA-ECC), steel fiber + PVA fiber reinforced ECC (defined as HyFRECC-A) and steel fiber + PVA fiber + CaCO3 whisker reinforced ECC (defined as HyFRECC-B) subject to room temperature and 200 ℃, 400 ℃, 600 ℃, 800 ℃ elevated temperature exposure were experimentally compared. The results indicate that equally replacing PVA fibers by steel fibers degraded the flexural hardening ability of PVA-ECC at room temperature, while the addition of appropriate amount of CaCO3 whisker improved the flexural strength, toughness and flexural hardening behavior. The elevated temperature posed a significant effect on the flexural strength and toughness of the three types of ECCs. Flexural deflection hardening behavior of the three types of ECCs was eliminated after high temperature exposure. Flexural strength and toughness of PVA-ECC presented an exponential decay along with the increase of temperature. The addition of steel fiber slowed down the decay rate. Although the use of CaCO3 whisker increased the post-temperature flexural strength and toughness of HyFRECC-B, the decay rate was not further decreased.

scholarly journals Effect of different PVA and steel fiber length and content on mechanical properties of CaCO3 whisker reinforced cementitious composites

2019 ◽  
Vol 69 (336) ◽  
pp. 200 ◽  
Author(s):  
M. Cao ◽  
C. Xie ◽  
L. Li ◽  
M. Khan
Keyword(s):  
Mechanical Properties ◽  
Crack Resistance ◽  
Fiber Length ◽  
Large Deflection ◽  
Steel Fiber ◽  
Flexural Behavior ◽  
Cementitious Composites ◽  
Hybrid Fiber ◽  
Pva Fiber ◽  
Fiber Reinforced Cementitious Composites

In this paper, calcium carbonate (CaCO3) whisker as a fiber reinforcement is mixed with steel and PVA fiber to form a multiscale hybrid fiber reinforced cementitious composites (MHFRCC). ASTM standard and post-crack strength techniques are performed to evaluate the mechanical properties of MHFRCC. The 1.25 % long steel fiber, 0.55 % short PVA fiber and 2.0 % CaCO3 whisker specimens showed the best flexural behavior before L/600 deflection. However, 1.5 % long steel fiber, 0.4 % long PVA fiber and 1.0 % CaCO3 whisker specimens presented better crack resistance after L/600 deflection. It is revealed that flexural parameters increase as comprehensive reinforcing index increase. The result showed that the CaCO3 whisker and short PVA fiber provided crack resistance effect at micro-scale and mainly play a dominate role in inhibiting micro-cracking. However, long steel fiber and long PVA fiber showed a better bridging effect of macro cracks at a large deflection.

Orthogonal Experimental Study on Properties of Hybrid Fiber Reinforced Cement Mortar

2010 ◽  
Vol 168-170 ◽  
pp. 456-459
Author(s):  
Hai Yan Yuan ◽  
Shui Zhang ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Cement Mortar ◽  
Polypropylene Fiber ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Factors Affecting ◽  
Fiber Fraction ◽  
Reinforced Cement

By adopting the method of orthogonal experimental design, the effect of three independent variables, that is steel fiber fraction, polypropylene fiber fraction and silica fume fraction on the compressive strength, flexural strength and shrinkage of cement mortar was studied. The results indicate that steel fiber is one of the most important factors affecting compressive strength and shrinkage, and polypropylene fiber is one of the most important factors affecting flexural strength and shrinkage of cement mortar. By using deviation analysis to analyze the orthogonal experiment results, the optimized mix proportion of hybrid fiber reinforced cement mortar is determined. The hybrid effect of steel fiber and polypropylene fiber on the properties of cement mortar is discussed.

The Influence on High-Temperature Mechanical Properties of Hybrid-Fiber-Reinforced High-Performance Concrete and Microscopic Analysis

2012 ◽  
Vol 226-228 ◽  
pp. 1709-1713
Author(s):  
Lan Yan ◽  
Y.M. Xing ◽  
Ji Jun Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Transition Zone ◽  
High Performance ◽  
Room Temperature ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Interfacial Transition Zone ◽  
Hybrid Fiber ◽  
High Temperature Mechanical Properties

This paper investigated the high temperature mechanical properties of the hybrid fiber reinforced high performance concrete (HFHPC) and normal concrete (NC) .After being subjected to different elevated heating temperatures, two kinds of concretes have been tested for the compressive strength, splitting tensile strength and flexural strength of test specimen at room temperature and 200 °C,400 °C,600 °C,800 °C.Microstructure changes of concrete were also observed by using Scanning Electron Microscopy (SEM) after high temperature. The results show that the hybrid fiber can significantly increase mechanical properties of the concrete at room temperature and high temperature. SEM and XRD analysis shows that there is a permeable diffusion layer in the steel fiber surface because of solid state reaction in the Interfacial Transition Zone of steel fiber and concrete. This permeable diffusion layer is white, bright, serrated and mainly consist of FeSi2 and the complex hydrated calcium silicate. The compounds of this layer change the Interfacial Transition Zone structure, enhance bonding capacity of the steel fiber and matrix, and increase the high temperature mechanical properties of concrete.

Thermal Properties of PVA-Fiber Reinforced Cement Composites at High Temperatures

2013 ◽  
Vol 377 ◽  
pp. 45-49 ◽  
Author(s):  
Eva Vejmelková ◽  
Robert Černý
Keyword(s):  
High Temperature ◽  
Cement Composites ◽  
Transient Method ◽  
Fiber Reinforced ◽  
Sample Heating ◽  
Vacuum Saturation ◽  
Reinforced Cement ◽  
Saturation Method ◽  
Temperature Exposure ◽  
Pva Fiber

Properties of polyvinyl alcohol-fiber reinforced cement composites are investigated as functions of temperature up to 1000 °C. Basic physical properties are measured using the water vacuum saturation method. High-temperature thermal diffusivity is determined by a transient method based on the analysis of temperature field at one-sided sample heating. High-temperature specific heat capacity is obtained using a non-adiabatic method. Experimental results show that the studied material exhibits a satisfactory resistance to high-temperature exposure and has a potential for using in high-temperature applications in building industry.

scholarly journals Effect of Exposure to High Temperature on the Mechanical Properties of SIFRCCs

2020 ◽  
Vol 10 (6) ◽  
pp. 2142
Author(s):  
Seungwon Kim ◽  
Topendra Oli ◽  
Cheolwoo Park
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Fire Resistance ◽  
Fiber Reinforced ◽  
High Temperature Exposure ◽  
Organic Fiber ◽  
Compressive And Flexural Strengths ◽  
Temperature Exposure ◽  
Concrete Model

Many researchers have studied explosion prevention and fire resistance of high-strength concrete mixed with organic fiber and steel fibers. The fire resistance of high-performance fiber reinforced cement composites is desirable in terms of physical and mechanical properties. However, the use of a polymer as an alternative to organic fiber has not been clearly studied. In this study, a slurry infiltration method was used to obtain slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs) specimens. Powder polymer was used instead of organic fibers during mixing of the slurry. The compressive and flexural strengths of the specimens after 1 hr of high temperature exposure according to the KS F 2257 (ISO 834) standard fire-temperature curve were measured. The addition of the polymer before and after high temperature (about 945 °C) exposure affected the strength of the SIFRCCs. The compressive and flexural strengths were decreased after exposure to high temperature in comparison with SIFRCCs without polymer because polymer create capillary pores due to melting and burning when exposure to high temperature. This minimizes the vapor pressure inside the concrete model and reduces the failure of the concrete model. The experimental results showed that the flexural strength at a high temperature for 1.0 % polymer content was the highest at 53.8 MPa. The flexural strength was reduced by 40~50% when compared to the flexural strength before high temperature exposure and comparing to SIFRCCs without polymer, the compressive strength in 1.5% polymer is lower, owing to voids that are created in the SIFRCCs after exposure to a high temperature.

Splitting Strength of Hybrid Fiber Reinforced Concrete after Exposure to Elevated Temperatures

2011 ◽  
Vol 71-78 ◽  
pp. 1695-1702 ◽  
Author(s):  
Han Li ◽  
Dan Ying Gao
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Steel Fiber ◽  
Strength Loss ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Significant Deterioration ◽  
Splitting Strength

Experiments were carried out to investigate the splitting properties of hybrid fiber reinforced concrete after exposure to elevated temperatures. Based on the experimental observation, the effect of steel fiber dosage, polypropylene (PP) fiber dosage and strength grade of concrete on the residual splitting strength of the concrete after being subjected to high temperature was systematically analyzed. Test data indicated that high temperature caused significant deterioration in the splitting strength of concrete; the addition of PP fiber and steel fiber could all effectively improve the residual splitting properties of concrete; the optimum amount of PP fiber and steel fiber were identified respectively; the degree of strength loss of concrete with different strength grades was very close to each other. A theoretical equation was proposed to predict the residual splitting strength of concrete after being heated to temperatures up to 800°C.

scholarly journals Study on Mechanical Properties and Constitutive Equation of Hybrid Fiber Reinforced Cementitious Composites Under Static Loading

2016 ◽  
Vol 10 (1) ◽  
pp. 482-491 ◽  
Author(s):  
Huixian Yang ◽  
Jing Li ◽  
Yansheng Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Steel Fiber ◽  
Cementitious Composites ◽  
Peak Strain ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Stress Strain ◽  
Fiber Reinforced Cementitious Composites

The Quasi-static mechanical properties of hybrid fiber (steel fiber and Polyvinyl alcohol (PVA) fiber) reinforced cementitious composites (HFRCC(SP)) were investigated by compressive and tensile experiments. The compressive strength, peak strain, elastic modulus and tensile strength are studied as compared with that of engineered cementitious composite (ECC). Study results indicate that steel fibers can improve the compressive and tensile strength of HFRCC(SP) but the peak strain of HFRCC(SP) decreases. The formulas modified based on codes are proposed to calculate compressive peak strain, elastic modulus and tensile strength. The relationship between tensile strain at peak load and tensile strength of HFRCC with different volume fractions of polyethylene fiber and steel fiber were studied and the tensile stress-strain relation was presented. The parameters k1 and k2 of constitutive formulas for fiber reinforced high strength concrete presented by Mansur are modified to describe the stress-strain curve of HFRCC(SP), the modified formulas show good agreement with the experimental results.

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