Axial Compressive Behavior of Predamaged Concrete Cylinders Retrofitted with CFRP Grid-Reinforced ECC

Data Availability Statement

Acknowledgments

Notation

A_cor

cross-sectional area of the original concrete cylinders;

A_e

cross-sectional area of CFRPECC;

a, b

parameters of the compressive stress–strain model for ECC;

D

diameter of concrete cylinders;

d_c

compressive damage index;

E_c, E_co, E_cc, E_cc,d

initial elastic moduli of CFRPECC-retrofitted concrete, plain concrete, CFRPECC-confined intact and predamaged concrete, respectively;

E_ce

initial compressive elastic modulus of ECC;

E_en,co, E_en,cc

energy dissipation indexes of the plain concrete and the CFRPECC-retrofitted concrete, respectively;

E_f

tensile elastic modulus of FRP grids;

E_m

tensile elastic modulus of ECC;

E_t

tensile elastic modulus of CFRPECC;

E₁, E_1,d

initial elastic moduli of compressive stress–strain model for the confined intact and predamaged concrete, respectively;

E₂, E_2,d

postpeak moduli of compressive stress–strain model for the confined intact and predamaged concrete, respectively;

$f_{co}^{\mathrm{\prime }}$

compressive strength of plain concrete;

$f_c^{\mathrm{\prime }}$, $f_{cc}^{\mathrm{\prime }}$, $f_{cc,d}^{\mathrm{\prime }}$

strengths of CFRPECC-retrofitted concrete, CFRPECC-confined intact concrete, and CFRPECC-confined predamaged concrete, respectively;

$f_{ce}^{\mathrm{\prime }}$

compressive strength of ECC;

$f_{ep}^{\mathrm{\prime }}$

strength of CFRPECC-retrofitted concrete directly carried by CFRPECC;

f_l,p

lateral confinement stress of CFRPECC at the strength of CFRPECC-retrofitted concrete;

f_t,0

Y-intercept strength of the second stage of tensile stress–strain curve of CFRPECC;

f_un

stress of the unloading point based on the predamage level;

f₀, f_0,d

intercept strengths of the Y-axis by the postpeak stage of the stress–strain curve of CFRPECC-retrofitted intact and predamaged concrete, respectively;

m, n

parameters of the compressive stress–strain model for ECC;

n_c

shape parameter of the second stage of the tensile stress–strain curve of CFRPECC;

n_g

number of CFRP grids;

n₀

shape parameter controlling the transition stage curvature of the stress–strain curve of confined concrete;

t_f

nominal thickness of CFRP grids;

t_te

thickness of CFRPECC;

α, β, γ

parameters in the tensile stress–strain models of CFRPECC;

α_d, β_d, γ_d

reduction factors describing the reduction of the strength, peak strain, and elastic modulus between the CFRPECC-confined predamaged and intact concrete, respectively;

ɛ

certain strain value on the compressive stress–strain curve of plain concrete;

ɛ_c

axial compressive strain of FRP-jacketed concrete;

ɛ_co, ɛ_cc, ɛ_cc,d

strains corresponding to $f_{co}^{\mathrm{\prime }}$, $f_{cc}^{\mathrm{\prime }}$, and $f_{cc,d}^{\mathrm{\prime }}$, respectively;

ɛ_ce, ɛ_ce,0.4

strains at f_ce and 0.4 f_ce, respectively;

ɛ_cr

cracking strain of ECC (0.00015);

ɛ_h,u

lateral rupture strain at $f_c^{\mathrm{\prime }}$;

ɛ_pl

concrete plastic strain under unloading to zero stress;

ɛ_ss

strain at the beginning of the strain-hardening stage of the tensile stress–strain curve of CFRPECC;

ɛ_t

tensile strain of CFRPECC;

ɛ_tu

ultimate tensile strain of CFRPECC;

ɛ_u

ultimate compressive strain of ECC;

ɛ_un

stress of the unloading point based on the predamage level;

λ

energy dissipation enhancement ratio;

σ_c, σ_cc, σ_cc,d

compressive stresses of CFRPECC-retrofitted concrete, CFRPECC-confined intact concrete, and CFRPECC-confined predamaged concrete, respectively;

σ_ce

compressive stress of ECC;

σ_co

compressive stress of plain concrete;

σ_cr

tensile cracking stress of CFRPECC;

σ_ss

stress at the beginning of the strain-hardening stage of the tensile stress–strain curve of CFRPECC; and

σ_t

tensile stress of CFRPECC.

References