Abstract

Carbon (CFRP) and glass (GFRP) fiber-reinforced composites of epoxy matrix are considered in the study, with greater emphasis on GFRP. Accelerated conditioning was imposed in the form of salt fog cycles, hygrothermal cycles (tap water), and tidal-like cycles (aqueous solution of NaCl, 50g/L), both on laminate composites and on beams externally reinforced with fiber-reinforced polymers (FRP) on their soffit. Freeze/thaw cycles were also applied to the study of degradation of the laminates. Mechanical tests showed degradation due to damage to the matrices, fiber-matrix linkage or bond between FRP and concrete. Several advanced techniques were used to interpret the results and enable better understanding of the phenomenological data. Changes on the glass transition temperature (Tg) of the epoxy matrix are reported as possible indicators of decrease of the tensile strength of the GFRP composite. Attention is given to the evolution of the relative values of the tensile strength of concrete and adhesive along time given their importance on the effectiveness of the FRP-adhesive-concrete joints. The results revealed, e.g.,that the more severe decrease of the carrying capacity of the beams was due to the salt fog cycles in the beams strengthened with CFRP.
Original languageEnglish
Article number04014092
JournalJournal of Materials in Civil Engineering
Volume26
Issue number12
DOIs
Publication statusPublished - Dec 2014

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Fog
Polymers
Salts
Fibers
Carbon fiber reinforced plastics
Composite materials
Concretes
Laminates
Adhesives
Tensile strength
Degradation
Glass fibers
Carbon
Water
carbon fiber reinforced plastic

Cite this

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title = "Composites and FRP-Strengthened Beams Subjected to Dry/Wet and Salt Fog Cycles",
abstract = "Carbon (CFRP) and glass (GFRP) fiber-reinforced composites of epoxy matrix are considered in the study, with greater emphasis on GFRP. Accelerated conditioning was imposed in the form of salt fog cycles, hygrothermal cycles (tap water), and tidal-like cycles (aqueous solution of NaCl, 50g/L), both on laminate composites and on beams externally reinforced with fiber-reinforced polymers (FRP) on their soffit. Freeze/thaw cycles were also applied to the study of degradation of the laminates. Mechanical tests showed degradation due to damage to the matrices, fiber-matrix linkage or bond between FRP and concrete. Several advanced techniques were used to interpret the results and enable better understanding of the phenomenological data. Changes on the glass transition temperature (Tg) of the epoxy matrix are reported as possible indicators of decrease of the tensile strength of the GFRP composite. Attention is given to the evolution of the relative values of the tensile strength of concrete and adhesive along time given their importance on the effectiveness of the FRP-adhesive-concrete joints. The results revealed, e.g.,that the more severe decrease of the carrying capacity of the beams was due to the salt fog cycles in the beams strengthened with CFRP.",
keywords = "Composite beams, Strength degradation, Composite materials, Epoxy, Composites, Strengthening, Durability",
author = "Silva, {Manuel Am{\'e}rico Gon{\cc}alves da} and Cidade, {Maria Teresa Varanda} and Hugo Biscaia and Rui Marreiros",
year = "2014",
month = "12",
doi = "10.1061/(ASCE)MT.1943-5533.0001008",
language = "English",
volume = "26",
journal = "Journal of Materials in Civil Engineering",
issn = "0899-1561",
publisher = "Asce American Society of Civil Engineers",
number = "12",

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T1 - Composites and FRP-Strengthened Beams Subjected to Dry/Wet and Salt Fog Cycles

AU - Silva, Manuel Américo Gonçalves da

AU - Cidade, Maria Teresa Varanda

AU - Biscaia, Hugo

AU - Marreiros, Rui

PY - 2014/12

Y1 - 2014/12

N2 - Carbon (CFRP) and glass (GFRP) fiber-reinforced composites of epoxy matrix are considered in the study, with greater emphasis on GFRP. Accelerated conditioning was imposed in the form of salt fog cycles, hygrothermal cycles (tap water), and tidal-like cycles (aqueous solution of NaCl, 50g/L), both on laminate composites and on beams externally reinforced with fiber-reinforced polymers (FRP) on their soffit. Freeze/thaw cycles were also applied to the study of degradation of the laminates. Mechanical tests showed degradation due to damage to the matrices, fiber-matrix linkage or bond between FRP and concrete. Several advanced techniques were used to interpret the results and enable better understanding of the phenomenological data. Changes on the glass transition temperature (Tg) of the epoxy matrix are reported as possible indicators of decrease of the tensile strength of the GFRP composite. Attention is given to the evolution of the relative values of the tensile strength of concrete and adhesive along time given their importance on the effectiveness of the FRP-adhesive-concrete joints. The results revealed, e.g.,that the more severe decrease of the carrying capacity of the beams was due to the salt fog cycles in the beams strengthened with CFRP.

AB - Carbon (CFRP) and glass (GFRP) fiber-reinforced composites of epoxy matrix are considered in the study, with greater emphasis on GFRP. Accelerated conditioning was imposed in the form of salt fog cycles, hygrothermal cycles (tap water), and tidal-like cycles (aqueous solution of NaCl, 50g/L), both on laminate composites and on beams externally reinforced with fiber-reinforced polymers (FRP) on their soffit. Freeze/thaw cycles were also applied to the study of degradation of the laminates. Mechanical tests showed degradation due to damage to the matrices, fiber-matrix linkage or bond between FRP and concrete. Several advanced techniques were used to interpret the results and enable better understanding of the phenomenological data. Changes on the glass transition temperature (Tg) of the epoxy matrix are reported as possible indicators of decrease of the tensile strength of the GFRP composite. Attention is given to the evolution of the relative values of the tensile strength of concrete and adhesive along time given their importance on the effectiveness of the FRP-adhesive-concrete joints. The results revealed, e.g.,that the more severe decrease of the carrying capacity of the beams was due to the salt fog cycles in the beams strengthened with CFRP.

KW - Composite beams

KW - Strength degradation

KW - Composite materials

KW - Epoxy

KW - Composites

KW - Strengthening

KW - Durability

U2 - 10.1061/(ASCE)MT.1943-5533.0001008

DO - 10.1061/(ASCE)MT.1943-5533.0001008

M3 - Article

VL - 26

JO - Journal of Materials in Civil Engineering

JF - Journal of Materials in Civil Engineering

SN - 0899-1561

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M1 - 04014092

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