Issue 50

A.G. Lekatou et alii, Frattura ed Integrità Strutturale, 50 (2019) 423-437; DOI: 10.3221/IGF-ESIS.50.36 434 Duration (m) Fly ash (wt.%) E (GPa) σ y 0.2% (MPa) σ t (MPa) σ f (MPa) %EL 0 0 200±1 597±15 780±28 751±40 44±1 15 200±1 610±27 782±23 751±27 42±0 20 199±0 586±15 754±16 707±9 43±1 25 199±0 592±8 753±11 707±16 42±1 2 0 200±0 592±14 763±22 731±22 41±1 15 196±0 552±40 726±49 690±45 40±1 20 194±1 577±22 749±21 704±27 40±2 25 190±0 595±24 767±28 717±34 41±1 4 0 190±1 573±11 739±14 718±11 37±1 15 189±2 599±12 783±13 750±13 41±2 20 189±3 571±56 738±81 680±47 40±4 25 188±1 572±20 732±19 709±22 38±0 Table 1 : Effect of fly ash content (of the dry concrete mixture) and salt spraying duration on the tensile properties of 304L rebars embedded in concrete. E: modulus of elasticity, σ y 0.2%: yield strength, σ t : tensile strength, σ f : fracture strength %EL: percent elongation. more consistent, in the cases of the modulus of elasticity and the percent elongation. The decrease in the elongation with time of corrosion is compatible with previous works [9,10], which showed that the influence of corrosion on the yield point and tensile strength of concrete steel reinforcement is markedly less than that on the elongation. This is because fracture starts from the point of pitting leading to brittle fracture [10]. Figure 9 : Effect of salt spraying time on the stress-strain behavior of 304L rebars embedded in concrete containing 25 wt.% fly ash. C ONCLUSIONS yclic potentiodynamic polarization of 304L stainless steel rebars in an acid rain simulating solution containing Ca(OH) 2 and different fly ash (FA) quantities at slightly acidic pHs has shown drastically limiting current regimes but some susceptibility to localized corrosion (10-20 wt.% FA). An increase in the FA addition (up to 20 wt.%) has resulted in an increase in the corrosion resistance. However, this trend was reversed at 25 wt.% FA. C