EFFECT OF HIGH TEMPERATURE ON BOND BETWEEN STEEL REINFORCEMENT

Bond behavior between steel reinforcement and fibrereinforced concrete under elevated temperature of upto 700 şC is evaluated using prismatic double pullout(DP) specimens. Five different high strength concrete(HSC) mixtures (with and without fibers) wereprepared using basalt aggregate at a w/c ratio of0.35. All specimens were cured for 28 days in acontrolled temperature-water bath at a degree of 40şC. Then specimens were subjected to heating by anelectrical furnace. Pullout specimens were testedunder pullout to evaluate the bond behavior betweensteel reinforcement bars and surrounding concretemixtures before and after heating. Cubes (100mm) castfrom same mixture, cured, and heat-treated undersimilar conditions were also tested to evaluatecompressive and splitting strength. The resultsshowed marked reductions in residual compressive,splitting and bond strengths of HSC under exposuretemperatures. DP concrete specimens with fibersshowed better bond behavior than that of HSC. Thiswas represented by higher residual bond strength, andsteel-bond ductility. Mixture incorporated H-steelfibers imparted the highest concrete-steel bondresistance against high temperatures