Properties of polyvinyl alcohol fiber reinforced fly ash based Engineered Geopolymer Composites with zeolite replacement

Novel hemp fiber reinforced geopolymer composites were fabricated. The matrix was a new geopolymer based on a mixture of red mud and fly ash. Chopped, randomly oriented hemp fibers were used as reinforcement. The mechanical properties of the geopolymer composite, such as diametral tensile (DTS) (or Brazilian tensile) strength and compressive strength (CS), were measured. The geopolymer composites reinforced with 9 vol.% and 3 vol.% hemp fiber yielded average DTS values of 5.5 MPa and average CS values of 40 MPa. Scanning electron microscopy (SEM) studies were carried out to evaluate the microstructure and fracture surfaces of the composites. The results indicated that the addition of hemp fiber is a promising approach to improve the mechanical strength as well as to modify the failure mechanism of the geopolymer, which changed from brittle to “pseudo-ductile”.

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Mix design and flexural toughness of PVA fiber reinforced fly ash-geopolymer composites

Construction and Building Materials ◽

10.1016/j.conbuildmat.2017.05.172 ◽

2017 ◽

Vol 150 ◽

pp. 179-189 ◽

Cited By ~ 27

Author(s):

Fang Xu ◽

Xin Deng ◽

Chao Peng ◽

Jing Zhu ◽

Jianping Chen

Keyword(s):

Fly Ash ◽

Mix Design ◽

Fiber Reinforced ◽

Flexural Toughness ◽

Pva Fiber ◽

Geopolymer Composites

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

Materials ◽

10.3390/ma13235539 ◽

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

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Crack Resistance and Mechanical Properties of Polyvinyl Alcohol Fiber-Reinforced Cement-Stabilized Macadam Base

Advances in Civil Engineering ◽

10.1155/2020/6564076 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Yi Zhao ◽

Xuan Yang ◽

Qingyu Zhang ◽

Naixing Liang ◽

Yangkai Xiang ◽

...

Keyword(s):

Mechanical Properties ◽

Polyvinyl Alcohol ◽

Crack Resistance ◽

Fiber Length ◽

Cement Content ◽

Strength Test ◽

Fiber Reinforced ◽

Polyvinyl Alcohol Fiber ◽

Reinforced Cement ◽

Shrinkage Property

A series of tests were carried out to evaluate crack resistance and mechanical properties of polyvinyl alcohol fiber-reinforced cement-stabilized macadam, which is widely used as pavement base or subbase composite material. Three series of cement-stabilized macadam mixtures with cement content of 3.2%, 3.6%, and 4.0% were prepared by incorporating four various contents (0, 0.6, 0.9, and 1.2 kg/m3) and lengths (12, 18, 24, and 30 mm) of polyvinyl alcohol fiber. The optimum polyvinyl alcohol fiber content, fiber length, and cement content were determined based on the mechanical properties of cement-stabilized macadam mixtures. Then, unconfined compressive strength test, compressive resilience modulus test, splitting strength test, flexural tensile strength test, drying shrinkage test, and temperature shrinkage test were carried out in this study. The results show that polyvinyl alcohol fiber-reinforced cement-stabilized prepared by optimum proportions (cement 3.6%, fiber content 0.9 kg/m3, and fiber length 24 mm) has good crack resistance. The incorporation of polyvinyl alcohol fiber can effectively improve compressive strength and splitting strength, while its effect on CRM of cement-stabilized macadam is not remarkable. The anti-dry-shrinkage property and anti-temperature-shrinkage property of the specimens are also drastically improved due to the reinforcement effect of polyvinyl alcohol fiber. Moreover, the crack resistance index is proposed to evaluate the crack resistance of materials. The crack resistance of PVA fiber-reinforced cement-stabilized macadam prepared by optimum proportions is improved by 44.4%. Consequently, the mechanical properties and crack resistance of cement-stabilized macadam are obviously improved by adding polyvinyl alcohol fiber.

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