Post-cracking behaviour of steel fibre reinforced concrete
Tóm tắt
Recently, RILEM TC 162-TDF has proposed equivalent,f
eq
, and residual,f
R
, flexural tensile strength parameters to characterize and simulate the post-cracking behaviour of steel fibre reinforced concrete (SFRC) structures. In the current work, more than two hundred flexural tests are carried out according to the RILEM TC 162-TDF recommendations and the corresponding values off
eq
andf
R
parameters are evaluated. In series of specimens reinforced with fibres of a distinct length/diameter ratio, similar values off
eq
andf
R
parameters were obtained in these series. Although a strong correlation betweenf
eq
andf
R
was determined, a larger scatter off
R
values was observed thereby revealingf
eq
to be more appropriate for design purposes. A numerical strategy involving a cross sectional layered model and an inverse analysis was developed to evaluate the post-cracking stress-strain and the stress-crack opening diagrams for the tested SFRC. This strategy was also used to determine a relation between the post-cracking strain, ɛ
pcr
, and the crack opening displacement,w, (ɛ
pcr
=w/L
p
) which is useful for evaluating the crack opening when numerical strategies based on a stress-strain approach are used. The obtainedL
p
values range from half the specimen cross section height to half the distance between the tip of the notch and the top of the cross section.
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