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Investigation of compressive bond behavior of steel and fiber reinforced polymer bars embedded in recycled aggregate concrete

University of British Columbia

Over the past several years, one of the important issues concerning the construction industry has been sustainable development. Therefore, usage of sustainable building materials and the reuse and recycling of previously used building materials have been considered in many areas. Recycling of construction and demolition (C&D) wastes could prevent their costly disposal which is hazardous to the environment. Utilization of demolished concrete as a coarse aggregate, often termed as recycled coarse aggregate (RCA) for producing industry quality concrete, could lead to a solution to the environmental conservation and pave the way towards sustainability by reducing the consumption of natural aggregate. During the development of this new generation product, it is essential to investigate the structural properties of reinforced RCA concrete to promote its application, in the construction industry. Besides, fiber reinforced polymer (FRP) composite rebars have been widely used in construction instead of steel rebars. Their non-corrosive nature and high tensile strength are the main reason of this replacement. Performance of reinforced concrete members at serviceability and ultimate limit states is controlled by the bond between reinforcement and concrete which is a critical design parameter. This research aims to evaluate RCA application in structural concrete and investigate the bond properties between reinforcing steel/FRP bars and RCA concrete. Bond performance of 35 MPa RCA concrete was assessed through an experimental plan. Five RCA replacement percentages and different diameters of reinforcing bars were used. Effects of embedment length and concrete cover to bar diameter ratio on the bond strength were moreover considered. It was observed that under constant mix proportions, an increase in the bar size and the embedment length to bar diameter ratio leads to a reduction in the bond strength due to growth of voids trapped between the bar surface and concrete. Like regular concrete, larger concrete cover helps improving the bond behavior. On average, acceptable bond strengths were observed in RCA samples which were close to control results. In addition, smaller bar diameter and larger concrete cover can improve bond behavior of specimens embedded with FRPs in comparison with steel ones.

Text

2016-04-27

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/57927

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/