Effect of Nano-Particle on Durability of Polyvinyl Alcohol Fiber Reinforced Cementitious Composite

2020 ◽  
Vol 12 (2) ◽  
pp. 249-262 ◽  
Author(s):  
Peng Zhang ◽  
Qingfu Li ◽  
Juan Wang ◽  
Yan Shi ◽  
Yuanxun Zheng ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Nano Particles ◽  
Nano Particle ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Cracking Resistance ◽  
Flow Measurements ◽  
Carbonation Resistance ◽  
Pva Fiber

In this study, the influence of nano-particle on flowability and durability of polyvinyl alcohol (PVA) fibers reinforced cementitious composite containing fly ash was evaluated. In the cementitious composite, Portland cement was replaced with 1.0%, 1.5%, 2.0% and 2.5% (by weight) of nano-particles. Two kinds of nano-particle of SiO2 and CaCO3 nano-particles were adopted in this study. PVA fibers were incorporated to the composite at a dosage of 0.9% (by volume). The flowability of the fresh cementitious composite was assessed using slump flow measurements. The durability of hardened cementitious composite includes carbonation resistance, permeability resistance, cracking resistance as well as freezing-thawing resistance, which were evaluated by the depth of carbonation, the water permeability height, cracking resistance ratio of the specimens, and relative dynamic elastic modulus of samples after freeze-thaw cycles, respectively. Our results showed incorporation of nano-particles had a little disadvantageous effect on flowability of PVA fiber reinforced cementitious composite, and the flowability of the fresh mixtures decreased with increases in the nano-particles content. The decrease in flowability of cementitious composite resulted by nano-SiO2 particles is more remarkable than nano-CaCO3 particles. The addition of both nano-SiO2 and nano-CaCO3 particles significantly improved the durability of PVA fiber reinforced cementitious composite. However, the improvement of nano-SiO2 on durability is much better than that of nano-CaCO3. When the amount of SiO2 nano-particle was less than 2.5%, the durability of cementitious composites increased with nano-SiO2 content. The microstructure of PVA fiber reinforced cementitious composite becomes much denser due to filler effect of nano-particle and generation of particles of hydrated products C–S–H gels. Both of SiO2 and CaCO3 nano-particle improved the microstructure of PVA fiber reinforced cementitious composite, and nano-SiO2 particles might be more beneficial for PVA fibers to play the role of reinforcement than nano-CaCO3 particles in the composites.

scholarly journals Effect of PVA fiber on durability of cementitious composite containing nano-SiO2

2019 ◽  
Vol 8 (1) ◽  
pp. 116-127 ◽  
Author(s):  
Peng Zhang ◽  
Qing-fu Li ◽  
Juan Wang ◽  
Yan Shi ◽  
Yi-feng Ling
Keyword(s):  
Volume Fraction ◽  
Fiber Content ◽  
Nano Particles ◽  
Cementitious Composites ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Cracking Resistance ◽  
Carbonation Resistance ◽  
Pva Fiber

Abstract In the current investigation, the influence of polyvinyl alcohol (PVA) fibers on flowability and durability of cementitious composite containing fly ash and nano-SiO2 was evaluated. PVA fibers were added into the composite at a volume fraction of 0.3%, 0.6%, 0.9%, and 1.2%. The flowability of the fresh cementitious composite was assessed using slump flow. The durability of cementitious composite includes carbonation resistance, permeability resistance, cracking resistance as well as freezing-thawing resistance, which were evaluated by the depth of carbonation, the water permeability height, cracking resistance ratio of the specimens, and relative dynamic elastic modulus of samples after freeze-thaw cycles, respectively. The results indicated that addition of PVA fibers had a little disadvantageous influence on flowability of cementitious composite, and the flowability of the fresh mixtures decreased with increases in PVA fiber content. Incorporation of PVA fibers significantly improved the durability of cementitious composites regardless of addition of nano-particles. When the fiber content was less than 1.2%, the durability indices of permeability resistance and cracking resistance increased with fiber content. However, the durability indices of carbonation resistance and freezing-thawing resistance began to decrease as the fiber dosage increased from 0.9% to 1.2%. The fiber reinforced cementitious composite exhibited better durability due to addition of nano-SiO2 particles. Nano-SiO2 particle improves microscopic structure of fiber reinforced cementitious composites, and the nano-particles are beneficial for PVA fibers to play the role of reinforcement in cementitious composites.

The Frontier Analysis of RCS for Micro-Nano Particle

2011 ◽  
Vol 337 ◽  
pp. 526-531 ◽  
Author(s):  
Chang Hua Du ◽  
Zhen Kang Li ◽  
Bin Liu ◽  
Chun Tian Li
Keyword(s):  
Composite Solder ◽  
High Hardness ◽  
Nano Particles ◽  
Nano Particle ◽  
Dispersion Strengthening ◽  
Creep Properties ◽  
Frontier Analysis ◽  
Technical Requirements ◽  
Reinforced Composite

By the method of adding MNP (micron or nano particles) into general solder, the composite electronic solder can be prepared, due to its role of solution or dispersion strengthening, and can improve the thermostable fatigue and creep properties of solder joint, it is also usually named as RCS (reinforced composite solder).Based on researchful analysis of RCS, such as metal particles, particles for high hardness, particles for low expansion coefficient, rare-earth particles and low aggregated particle, and of their reinforced mechanism, the technical requirements of RCS is found, it is also analyzed problems and application prospects of RCS.

scholarly journals Behavior Deterioration and Microstructure Change of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composite (PVA-ECC) after Exposure to Elevated Temperatures

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5539
Author(s):  
Qing Wang ◽  
Boyu Yao ◽  
Runze Lu
Keyword(s):  
Polyvinyl Alcohol ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
Polymer Fibers ◽  
Cementitious Composites ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Explosive Spalling ◽  
Polyvinyl Alcohol Fiber ◽  
Dense Microstructure

In the case of fire, explosive spalling often occurs in cementitious composites due to dense microstructure and high pore-pressure. Polymer fibers were proved to be effective in mitigating such behavior. However, deterioration of these fiber-reinforced cementitious composites inevitably occurs, which is vital for the prediction of structural performance and prevention of catastrophic disaster. This paper concentrates on the behavior and mechanism of the deterioration of polyvinyl alcohol fiber-reinforced engineered cementitious composite (PVA-ECC) after exposure to elevated temperatures. Surface change, cracking, and spalling behavior of the cubic specimens were observed at room temperature, and after exposure to 200 °C, 400 °C, 600 °C, 800 °C, and 1200 °C. Losses in specimen weight and compressive strength were evaluated. Test results indicated that explosive spalling behavior was effectively prevented with 2.0 vol% polyvinyl alcohol fiber although the strength monotonically decreased with heating temperature. X-ray diffraction curves showed that the calcium hydroxide initially decomposed in the range of 400–600 °C, and finished beyond 600 °C, while calcium silicate hydrate began at around 400 °C and completely decomposed at approximately 800 °C. Micrographs implied a reduction in fiber diameter at 200 °C, exhibiting apparent needle-like channels beyond 400 °C. When the temperature was increased to 600 °C and above, the dents were gradually filled with newly produced substance due to the synergistic effect of thermal expansion, volume expansion of chemical reactions, and pore structure coarsening

scholarly journals Shear Load-Displacement Curves of PVA Fiber-Reinforced Engineered Cementitious Composite Expansion Joints in Steel Bridges

2019 ◽  
Vol 9 (24) ◽  
pp. 5275
Author(s):  
Liqiang Yin ◽  
Shuguang Liu ◽  
Changwang Yan ◽  
Ju Zhang ◽  
Xiaoxiao Wang
Keyword(s):  
Composite Structure ◽  
Composite Structures ◽  
Shear Load ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Expansion Joints ◽  
Failure Characteristics ◽  
Engineered Cementitious Composite ◽  
Load Displacement ◽  
Pva Fiber

The concrete in the transition strips of expansion joints can become damaged prematurely during the service period. Polyvinyl alcohol (PVA) fiber-reinforced engineered cementitious composite (ECC) is a kind of high ductility concrete material, and its ultimate uniaxial tensile strain is more than 3%. It can be used to improve the damage status of expansion joints. Based on previous research results, ECCs were used in the pilot project of bridge expansion joints. Under this engineering background, the shear load-displacement curves of ECC expansion joints were studied through 27 groups of compression-shear tests of ECC/steel composite structures. The shear failure characteristics of ECC expansion joints were analyzed by the digital image correlation method. A shear load-displacement curve model of the composite structures was proposed based on the equivalent strain assumption and Weibull distribution theory. The results show that the failure mode of the composite structure specimens was ECC shear cracking. Stress and strain field nephograms were used to explain the failure characteristics of the composite structure specimens. The calculated curves of the shear load-displacement model of the composite structures were in good agreement with the experimental curves. The work is of great importance to the shear design of ECC expansion joints and their further engineering applications.

Flexural Behavior of Polyvinyl Alcohol Fiber–Reinforced Ferrocement Cementitious Composite

2021 ◽  
Vol 33 (4) ◽  
pp. 04021040
Author(s):  
Wenping Du ◽  
Canqian Yang ◽  
Chong Wang ◽  
Yong Pan ◽  
Honglei Zhang ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Flexural Behavior ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Polyvinyl Alcohol Fiber

Study on Friction and Wear Behavior of GCr15/1045 Steel under Nano-Particle Additive Conditions

2011 ◽  
Vol 189-193 ◽  
pp. 38-41
Author(s):  
Wen Jian Wang ◽  
Hong Zhuo ◽  
Jun Guo ◽  
Qi Yue Liu
Keyword(s):  
Friction And Wear ◽  
Wear Behavior ◽  
The Self ◽  
Nano Particles ◽  
Nano Particle ◽  
Friction And Wear Behavior ◽  
Repairing Effect ◽  
1045 Steel ◽  
Worn Surface

The aim of this study was to investigate the friction and wear behavior of GCr15/1045 steel under different nano-particle additive conditions using a reciprocating horizontal tribometer. The results indicate that the nano-particle additives could decrease friction coefficient of CGr15/1045 steel and reduce the wear of material compared with the dry condition. Nano-particles play an important role of polishing the micro-gibbosity of contact surfaces during the friction process. The nano-particles of Ca10(PO4)6, TiO2 and TiN can form the self-repairing film on the worn surface of 1045 steel. The analysis indicates that the self-repairing effect of nano-particle of TiN is best and the self-repairing effect of nano-particle of TiO2 is worst.

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