Evaluation of post-fire pull-out behavior of steel rebars in high-strength concrete containing waste PET and steel fibers: Experimental and theoretical study

• Published in: Construction & building materials Vol. 299; p. 123917
• Main Authors: Fakoor, Maziar, Nematzadeh, Mahdi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 13.09.2021
• Subjects: Bond behavior; Bond stress-slip response; Failure mode; High temperature; High-strength concrete; Prediction; Steel fiber-reinforced concrete (SFRC); Waste; WPET; Bond behavior; WPET; Bond stress-slip response; Failure mode; Prediction; Steel fiber-reinforced concrete (SFRC); High-strength concrete; High temperature; Waste
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.123917

•Post-fire bond performance between high-strength WPET concrete and steel rebar was studied.•Presence of steel fiber had a positive impact on the samples with the splitting failure mode.•With heating and incorporation of WPET replacing fine particles, the bond strength declined.•Multivariate prediction models were proposed for the bond behavior and bond-slip response. The present research addressed the post-fire bond performance between high-strength concrete incorporating waste polyethylene terephthalate (WPET) and steel reinforcement; a subject that had not been previously addressed. Further, the impact of incorporating steel fiber, as a commonly used material, into the mixture on the bond improvement was assessed. To this end, the content of WPET substituting for the fine aggregate by volume (0, 5, and 10%), volume fraction of steel fibers (0, 0.5, and 1%), applied temperature (25, 200, 400, and 600 °C) were considered as variables in a total of 108 samples that were produced. Afterward, the samples were subjected to the pullout test to examine different parameters. These parameters included the bond behavior, failure mode, bond stress-slip response, and bond strength-compressive strength behavior. Based on the results, with the incorporation of 5 and 10% volume content of WPET replacing fine particles, the bond strength declined by 4 and 26%, respectively, and as the temperature was raised, this reducing effect increased. Furthermore, the presence of steel fiber had a positive impact in the samples with the splitting failure mode, while it had a negligible or sometimes even negative impact in the samples with the pull-out failing mode. Lastly, multivariate prediction models were proposed for the bond behavior and bond-slip response as a function of the concrete compressive strength, WPET content, content of steel fiber, and the target temperature. Afterward, a comparison was made between the empirical results and the predictions of models developed by other researchers and the fib Model Code 2010 and ACI 408-12 codes.