Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester
Glass fiber-reinforced polymer (GFRP) reinforcing bars have relatively low shear strength, which limits their possible use in civil infrastructure applications with high shear demand, such as concrete reinforcing dowels. We suggest that the horizontal shear strength of GFRP bars can be significantly...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/13/24/5710 |
| _version_ | 1797544681501884416 |
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| author | Shreya Vemuganti Rahulreddy Chennareddy Amr Riad Mahmoud M. Reda Taha |
| author_facet | Shreya Vemuganti Rahulreddy Chennareddy Amr Riad Mahmoud M. Reda Taha |
| author_sort | Shreya Vemuganti |
| collection | DOAJ |
| description | Glass fiber-reinforced polymer (GFRP) reinforcing bars have relatively low shear strength, which limits their possible use in civil infrastructure applications with high shear demand, such as concrete reinforcing dowels. We suggest that the horizontal shear strength of GFRP bars can be significantly improved by nanomodification of the vinyl ester resin prior to pultrusion. The optimal content of functionalized multiwalled carbon nanotubes (MWCNTs) well dispersed into the vinyl ester resin was determined using viscosity measurements and scanning electron micrographs. Longitudinal tension and short beam shear tests were conducted to determine the horizontal shear strength of the nanomodified GFRP reinforcing bars. While the tensile strength of the GFRP reinforcing bars was improved by 20%, the horizontal shear strength of the bars was improved by 111% compared with the shear strength of neat GFRP bars pultruded using the same settings. Of special interest is the absence of the typical broom failure observed in GFRP when MWCNTs were used. Differential scanning calorimetry measurements and fiber volume fraction confirmed the quality of the new pultruded GFRP bars. Fourier-transform infrared (FTIR) measurements demonstrated the formation of carboxyl stretching in nanomodified GFRP bars, indicating the formation of a new chemical bond. The new pultrusion process using nanomodified vinyl ester enables expanding the use of GFRP reinforcing bars in civil infrastructure applications. |
| first_indexed | 2024-03-10T14:04:58Z |
| format | Article |
| id | doaj.art-83f6995500844efbb1a40742b8dc58e0 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T14:04:58Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-83f6995500844efbb1a40742b8dc58e02023-11-21T00:48:29ZengMDPI AGMaterials1996-19442020-12-011324571010.3390/ma13245710Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl EsterShreya Vemuganti0Rahulreddy Chennareddy1Amr Riad2Mahmoud M. Reda Taha3Department of Civil, Construction and Environmental Engineering, University of New Mexico, Albuquerque, NM 87131-0001, USADepartment of Civil, Construction and Environmental Engineering, University of New Mexico, Albuquerque, NM 87131-0001, USADepartment of Civil Engineering, Faculty of Engineering, Al-Azhar University, Cairo 11371, EgyptDepartment of Civil, Construction and Environmental Engineering, University of New Mexico, Albuquerque, NM 87131-0001, USAGlass fiber-reinforced polymer (GFRP) reinforcing bars have relatively low shear strength, which limits their possible use in civil infrastructure applications with high shear demand, such as concrete reinforcing dowels. We suggest that the horizontal shear strength of GFRP bars can be significantly improved by nanomodification of the vinyl ester resin prior to pultrusion. The optimal content of functionalized multiwalled carbon nanotubes (MWCNTs) well dispersed into the vinyl ester resin was determined using viscosity measurements and scanning electron micrographs. Longitudinal tension and short beam shear tests were conducted to determine the horizontal shear strength of the nanomodified GFRP reinforcing bars. While the tensile strength of the GFRP reinforcing bars was improved by 20%, the horizontal shear strength of the bars was improved by 111% compared with the shear strength of neat GFRP bars pultruded using the same settings. Of special interest is the absence of the typical broom failure observed in GFRP when MWCNTs were used. Differential scanning calorimetry measurements and fiber volume fraction confirmed the quality of the new pultruded GFRP bars. Fourier-transform infrared (FTIR) measurements demonstrated the formation of carboxyl stretching in nanomodified GFRP bars, indicating the formation of a new chemical bond. The new pultrusion process using nanomodified vinyl ester enables expanding the use of GFRP reinforcing bars in civil infrastructure applications.https://www.mdpi.com/1996-1944/13/24/5710pultrusionGFRPcarbon nanotubesvinyl estershear strength |
| spellingShingle | Shreya Vemuganti Rahulreddy Chennareddy Amr Riad Mahmoud M. Reda Taha Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester Materials pultrusion GFRP carbon nanotubes vinyl ester shear strength |
| title | Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester |
| title_full | Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester |
| title_fullStr | Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester |
| title_full_unstemmed | Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester |
| title_short | Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester |
| title_sort | pultruded gfrp reinforcing bars using nanomodified vinyl ester |
| topic | pultrusion GFRP carbon nanotubes vinyl ester shear strength |
| url | https://www.mdpi.com/1996-1944/13/24/5710 |
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