Effect of thermal cycling on bond between reinforcement and fiber reinforced concrete

• Published in: Cement & concrete composites 2004-08, Vol.26 (6), p.743-752
• Main Authors: Haddad, Rami H, Abendeh, Ra'ed M
• Format: Article
• Language: English
• ISSN: 0958-9465; 1873-393X
• DOI: 10.1016/S0958-9465(03)00083-0

The role of synthetic and short brass-coated steel fibers in preserving bond between reinforcing steel and concrete, subjected to cycles of heating and cooling, was investigated. The bond behavior was evaluated by means of cylindrical pullout specimens (75 × 150 mm) reinforced with 18 mm rebars embedded along the full length of the specimens. The specimens were prepared using fiber reinforced concrete mixes with polypropylene fibres at 0.15% and 0.30% (by vol) or with short brass-coated steel fibres at 0.5% (by vol). Standard cylinders (75 × 150 mm) were also cast in order to evaluate splitting tensile strength. After curing for 90 days, specimens were subjected to heating and cooling cycles of a temperature range from 35 to 150 °C during a period of 24 h; 4 h for heating and 20 h for cooling. The splitting tensile strength and bond behaviors were evaluated under cycles of heating and cooling of up to 80. The results showed that heating and cooling cycles caused a significant loss in splitting tensile and bond strengths after 80 cycles of heating and cooling that reached as high as 44% and 28%, respectively. Fibres contributions to preserving bond strength of reinforced concrete were dependent upon both fiber type and content. Results showed that the use of fibres would allow relatively high free-end slippage between embedded steel and reinforcement prior to failure. The study showed that the percentage loss in bond strength at various heating and cooling cycles was larger than that in splitting tensile strength.