"Relationship of Rheology, Fiber Dispersion, and Strengths of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composites"

2020 ◽  
Vol 117 (3) ◽  
Keyword(s):  
Polyvinyl Alcohol ◽  
Cementitious Composites ◽  
Fiber Reinforced ◽  
Fiber Dispersion ◽  
Polyvinyl Alcohol Fiber ◽  
Relationship Of ◽  
Fiber Reinforced Cementitious Composites

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

Experimental Study on Early Anti-Cracking Properties of Polyvinyl Alcohol Fiber Reinforced Cementitious Composites

2010 ◽  
Vol 34-35 ◽  
pp. 1445-1448 ◽  
Author(s):  
Shu Guang Liu ◽  
Cun He ◽  
Chang Wang Yan ◽  
Xiao Ming Zhao
Keyword(s):  
Polyvinyl Alcohol ◽  
Crack Width ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Cementitious Composites ◽  
Fiber Volume ◽  
Polyvinyl Alcohol Fiber ◽  
Maximum Crack ◽  
Pva Fiber ◽  
Fiber Reinforced Cementitious Composites

This paper mainly studies early anti-cracking of cementitious composites containing polyvinyl alcohol (PVA) fiber and fly ash (FA). The PVA fibers were added at the volume fractions of 0%, 0.25%, 0.5%, 1.0% and 2.0%. The percentages of FA used in the experiment were 0% and 15%. Experimental results show that the maximum crack width and total crack area can be reduced with the increase of volume fraction of PVA fiber, and that no crack appeared at the volume fraction of 2.0%. The reducing tendency of crack width and total crack area kept constant with addition of FA, but reducing amplitude decreased. When the PVA fiber volume fraction remains constant, the early anti-cracking properties of cementitious composites containing PVA fiber and common cement are superior to one containing PVA fiber and FA. Conclusions can be drawn that the early anti-cracking properties of cementitious composites can be improved by PVA fiber.

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