Flexural performance of reinforced beams made with composite ferronickel slag concrete. (6th December 2021)

• Record Type: Journal Article
• Authors: Liu, Xuhong; Chen, Shanghong; Qi, Ai; Lin, Wei; Wu, Huanqiang
• Is Part Of: Construction & building materials. Volume 310(2021)
• Publication Date: 2021-12-06
• Subjects: Composite ferronickel slag concrete -- Flexural capacity -- Ductility -- Tie bar model -- Tensile rigidity effect -- Plastic rotation ability; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.125251
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: As F-S powder content increases, the flexural crack spacing increases. F-S concrete strength is an important factor ensuring the flexural capacity. Concrete strength affects the ductility of RC beams. F-S concrete with required strength can be applied in beams. Abstract: Concrete containing ferronickel slag with blast furnace slag, namely composite ferronickel slag concrete or F-S concrete, is featured by low bond strength with horizontally-placed rebar compared with normal concrete of equal strength. This feature may affect the flexural capacity and deformational characteristic of F-S concrete beams, which needs to be investigated. Four under-reinforced beams were prepared and tested, including one normal concrete beam and three F-S concrete beams. The variable was the percentages of F-S powder content, i.e., 0%, 20%, 30%, and 40%. The experimental results showed that as F-S powder content increased, both the flexural capacity and ductility of RC beams decreased. For the flexural capacity analysis, directly increasing F-S powder content lowers concrete strength, thus reducing the flexural capacity. Regarding the deformational characteristic analysis, the RC beam is ideally simplified to the combination of the compressive concrete column model plus the tie bar model, and the influence of tensile rigidity effect with different bond level on the tie bar deformation is mainly studied. It is found that the lower bond stress just increases the flexural crack spacing, and changes the stress and strain distribution of rebar and concrete, but does not change the stress-mean strain relation of the rebar in the tie bar per unit length. The incorporation of F-S powder has no effect on the deformation of RC beams. Unexpectedly, the concrete strength is another important factor affecting the plastic rotation ability of RC beams. Whether increasing/decreasing the concrete strength will increase or decrease the ductility of RC beams, it is much determined by the given ratio of the longitudinal tensile reinforcement. In other words, while F-S concrete strength equals that of normal concrete, the ductility of the F-S concrete beam resembles that of normal concrete beam. F-S concrete can be applied in engineering structures, as long as it meets the design strength requirement as normal concrete does, irrespective of any F-S powder content.