2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
Effect of superabsorbent polymer on mitigating damages at steel bar-concrete interface

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Author(s)
Mr. Seyed Sina Mousavi Ojarestaghi, École de technologie supérieure (Presenter)
Dr. Claudiane Ouellet-Plamondon, École de technologie supérieure
Dr. Lotfi Guizani, École de technologie supérieure
Abstract

Autogenous healing capacity of concrete has been considered in the last decades as a smart ability for mitigating internal damages in concrete structures. However, there is no specific research for healing cracks at rebar-concrete interfaces. Superabsorbent polymer (SAP) was used in this study inside the mixture to produce SAP concrete as a smart generation of concrete for autogenously healing cracks perpendicular to the rebar direction. An experimental program was conducted to check the performance of SAP as a healing agent in comparison with the reference mix. Two types of SAP particle sizes were considered and tested in this program with 0.25 %wt. of cement. Splitting test (Brazilian) was used to simulate pre-cracking at rebar-concrete interface. Controlled displacement loading with the rate of 0.15 mm/min was applied to prevent unexpected splitting failure during pre-cracking process. Although crack gauges were installed at both sided of specimens to control crack width limitation, ultimate crack width was measured directly after stopping the test. Two period of 14 and 28 days were considered for healing internal damages. Although bond strength is relatively lower in SAP-based concrete compared to the normal concrete because of macro pores at SAP locations, results show a good healing effect for initial bond strength, maximum bond strength, and energy absorbed by bond mechanism, within the cracks of cracked SAP-based concrete subjected to wet-dry recurring cycles. Results indicate that particle size of SAP has no significant effect on 28-day compressive strength and also rebar-concrete bond strength. Generally, findings evidently support the hypothesis that concrete composition could be a key parameter for controlling cracks at rebar-concrete interfacial surfaces. Obtained results show that concrete with SAP shows higher healing capacity compared to the concrete without SAP.