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Advance Repairing Technique for Enhancement of Stiffness of Post-Heated Concrete Cylinders

DOI:10.1007/s42107-020-00340-1
Authors:
Muhammad Usman at University of Engineering and Technology, Lahore
Muhammad Usman
Muhammad Yaqub
Muhammad Yaqub
Muhammad Yaqub
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Afaq Ahmad at The University of Memphis
Afaq Ahmad
Usman Muhammad at Liaoning ShiHua University
Usman Muhammad
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Abstract

The present study aims to investigate the effectiveness of epoxy injection on the performance of post-heated concrete cylinders confined with carbon fibre reinforced polymer composites (CFRP). A total of 42 of standard dimensions (diameter of 150 mm x 300 mm) were tested under uni-axial compression. These cylinders were divided in to two groups regarding the heating i.e. un-heated and post-heated. Furthermore, the post-heated concrete specimens were further divided into four specimen groups with respect to various temperatures i.e. 400ºC, 600ºC, 700ºC and 800ºC and then cooled to room temperature. The axial compressive behaviour of un-heated unconfined (UHUC), un-heated CFRP confined (UHC), post-heated unconfined (PHUC), post-heated CFRP confined (PHC) and epoxy injected post-heated CFRP confined concrete cylinders (PHEC) were investigated in terms of axial compressive strength (fc'), stiffness (k), energy dissipation capacity (EDC) and restorability. The test results showed that CFRP confinement can significantly enhance the fc', and EDC of the PHC subjected to the mentioned temperatures. Furthermore, the CFRP confinement effectiveness was increased with increasing the level of fire damage (i.e. at higher temperature). It was found that the fc' of PHEC at 400ºC was restored up to the design value of UHUC. However, the PHEC was unsuccessful for restoring the design value for the temperatures higher than 400ºC.
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1
Advance Repairing Technique for Enhancement of Stiffness of
Post-Heated Concrete Cylinders
Muhammad Usman1, Muhammad Yaqub2, Afaq Ahmad3*, Muhammad Usman Rashid4
1 M.Sc Student, Civil Engineering Department, Univeristy of Engineering & Technology Taxila, Pakistan Email:
m.usman@gamil.com
2 Professor , Civil Engineering Department, Univeristy of Engineering & Technology Taxila, Pakistan Email:
muhammad.yaqub@uettaxila.edu.pk
3 Assistant Professor, Civil Engineering Department, Univeristy of Engineering & Technology Taxila, Pakistan
Email: afaq.ahmad@uettaxila.edu.pk (Corresponding Author)
4 PhD Student, Civil Engineering Department, Univeristy of Engineering & Technology Taxila, Pakistan
Email m.usman@uettaxila.edu.pk)
Abstract
The present study aims to investigate the effectiveness of epoxy injection on the performance of post-heated concrete
cylinders confined with carbon fibre reinforced polymer composites (CFRP). A total of 42 of standard dimensions
(diameter of 150 mm x 300 mm) were tested under uni-axial compression. These cylinders were divided in to two groups
regarding the heating i.e. un-heated and post-heated. Furthermore, the post-heated concrete specimens were further
divided into four specimen groups with respect to various temperatures i.e. 400ºC, 600ºC, 700ºC and 800ºC and then
cooled to room temperature. The axial compressive behaviour of un-heated unconfined (UHUC), un-heated CFRP
confined (UHC), post-heated unconfined (PHUC), post-heated CFRP confined (PHC) and epoxy injected post-heated
CFRP confined concrete cylinders (PHEC) were investigated in terms of axial compressive strength (fc’), stiffness (k),
energy dissipation capacity (EDC) and restorability. The test results showed that CFRP confinement can significantly
enhance the fc’, and EDC of the PHC subjected to the mentioned temperatures. Furthermore, the CFRP confinement
effectiveness was increased with increasing the level of fire damage (i.e. at higher temperature). It was found that the fc’
of PHEC at 400ºC was restored up to the design value of UHUC. However, the PHEC was unsuccessful for restoring the
design value for the temperatures higher than 400ºC.
Keywords: Temperature; Epoxy Injection; CFRP; Strength, Post-heated Concrete
Abbreviations and Symbols
CFRP = Carbon Fibre Reinforced Polymer
EDC= Energy Dissipation Capacity
LD = Load Displacement
UHUC = Un-Heated Un-Confined
UHC = Un-Heated CFRP Confined
Manuscript Click here to access/download;Manuscript;PAPER-2020-06-
06.docx
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