Material Factor for GFRP RC Structures in Canada

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1648 ◽

2013 ◽

Vol 671-674 ◽

pp. 1648-1651

Author(s):

Jian Wei Huang

Keyword(s):

Safety Margin ◽

Design Codes ◽

Degradation Mechanisms ◽

Rc Structures ◽

Gfrp Bar ◽

Current Design ◽

Material Factor ◽

Long Term Performance ◽

Term Performance

Degradation mechanisms of GFRP bar in real concrete are still not clear to civil engineers due to limited field applications. To avoid unsafe design, in current design codes a material factor is used to assure long-term safety of GFRP RC structures. This paper presents an assessment of material factors for GFRP bar as specified in Canadian Design Codes by predicting GFRP long-term performance with monthly average temperatures from 14 weather reporting stations in Canada. Results showed that the material factor varies from 0.57 to 0.61 for an application with 100% RH exposure, while a factor of 0.75 could be adequate for cases with exposure RH ≤90%. Considering the annual relative humidity across Canada, conclusion could be made that current factors in Canadian codes could provide sufficient safety margin.

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An Investigation of Environmental Reduction Factor for GFRP Bar Used as Concrete Reinforcement in China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.413.399 ◽

2011 ◽

Vol 413 ◽

pp. 399-403 ◽

Cited By ~ 1

Author(s):

Jian Wei Huang

Keyword(s):

Reduction Factor ◽

Fiber Reinforced Polymer ◽

Rc Structures ◽

Average Temperature ◽

Reinforced Polymer ◽

Gfrp Bar ◽

Temperature Records ◽

Long Term Performance ◽

Term Performance

Currently, an environmental reduction factor (ERF) is incorporated in design codes/guidelines of Fiber Reinforced-Polymer (FRP) in reinforced concrete (RC) structures to account for the FRP long-term durability. Due to the lack of real time durability data, justification of the ERF is still necessitated. This paper presents a calibration of ERF for GFRP bar to be used in China on the basis of the prediction of GFRP long-term performance with monthly average temperature records from 32 major cities. Research results show that the ERF values vary from 0.49 to 0.58 at 100% R.H. exposure, while ERFs are greater than 0.70 for all cases being studied when R.H. is below 90%. On the basis of this study, ERF can be recommended as of 0.70 and 0.50 for application with R.H. <90% and moisture saturated exposures, respectively.

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Input Parameters for the Mechanistic-Empirical Design of Full-Depth Reclamation Projects

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211017916 ◽

2021 ◽

pp. 036119812110179

Author(s):

Vishwa V. Beesam ◽

Cristina Torres-Machi

Keyword(s):

Pavement Design ◽

Design Parameters ◽

Future Research ◽

Limited Information ◽

Full Depth Reclamation ◽

Input Parameters ◽

Current Design ◽

Long Term Performance ◽

Term Performance

Cold recycling technologies such as full-depth reclamation (FDR) are sustainable and cost-effective techniques for pavement rehabilitation that reduce environmental impacts and construction costs and time. The limited information available on the material properties of FDR mixtures and their characterization in mechanistic-empirical (M-E) pavement design hinders the full deployment of FDR. Previous research has found current M-E default values to be non-representative and overly conservative, leading to an underestimation of the true performance capabilities of FDR materials. To address this gap, this paper analyzes the performance of 11 FDR sites constructed throughout Colorado, U.S., and compares their long-term performance with M-E predictions. The objective of this paper is to recommend input values for the M-E design of FDR base materials that result in reliable predictions of FDR long-term performance. The analysis includes both non-stabilized and emulsion-stabilized FDR projects. Both initial International Roughness Index (IRI) and resilient modulus were found to have a significant impact on M-E predictions and were calibrated in a two-step process. The proposed input parameters lead to a conservative design of FDR projects and result in improved IRI predictions compared with the ones derived from current design criteria. With the current design parameters, IRI predictions were, on average, overestimated by 51 in./mi, whereas the proposed input parameters make it possible to reduce this difference to 17 in./mi. Future research is needed to improve current models in M-E pavement design software to adequately model cold in-place recycled layers such as FDR.

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Prestressed near-surface mounted fibre reinforced polymer reinforcement for concrete structures — a review

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2013-0063 ◽

2013 ◽

Vol 40 (11) ◽

pp. 1127-1139 ◽

Cited By ~ 38

Author(s):

Raafat El-Hacha ◽

Khaled Soudki

Keyword(s):

Near Surface ◽

Rc Structures ◽

Reinforced Polymer ◽

External Prestressing ◽

Fibre Reinforced Polymer ◽

Frp Reinforcement ◽

Near Surface Mounted ◽

Long Term Performance ◽

Term Performance

The specialized application of prestressing the near-surface mounted (NSM) fibre reinforced polymer (FRP) reinforcement for strengthening reinforced concrete (RC) structures combines the benefits of the FRP reinforcement with the advantages associated with external prestressing. By applying a prestress to the NSM FRP the material is used more efficiently since a greater portion of its tensile capacity is employed. This paper presents a comprehensive review on the performance of RC members strengthened using prestressed NSM FRP reinforcement. Several techniques and anchorage systems developed to prestress the NSM FRP are presented. The static flexural and fatigue performance of RC beams strengthened using prestressed NSM FRP in comparison to non-prestressed NSM is presented. Research on the long-term performance under freeze–thaw exposures and sustained loading is also presented.

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Long-Term Performance Prediction of GFRP Bar in Moist Concrete under Sustained Loads

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.255-260.3119 ◽

2011 ◽

Vol 255-260 ◽

pp. 3119-3123 ◽

Cited By ~ 6

Author(s):

Jian Wei Huang

Keyword(s):

Tensile Strength ◽

Temperature Shift ◽

Strength Loss ◽

Sustained Load ◽

Gfrp Bar ◽

Sustained Loads ◽

Reported Data ◽

Long Term Performance ◽

Term Performance

In this paper, the tensile strength retention of GFRP bars embedded in moist concrete under sustained loads is discussed on the basis of reported data. Long-term performance of GFRP bar is predicted by a newly developed model through time-temperature shift and time extrapolation approaches. Results indicated that higher temperature and longer exposure time result in more tensile strength loss of the sustained GFRP bar in moist concrete. Above certain temperature, GFRP bar in moist concrete with about 20% sustained load fails in rupture of GFRP bar for 75-year design lifetime. The temperature effect shall be taken into account in the design codes/guidelines.

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