Interfacial Bonding Strength in Cement Mortar Beams Reinforced with Metamaterial Bars

Abstract

Reinforced concrete beam (RCB) elements show low mechanical performance when interfacial bonding strength (IBS) is not well controlled. New tailorable material-structure arrangements -Metamaterials -offer solutions to the IBS problem. This paper analyzes the mechanical characteristics of IBS on RCBs for reinforced cement mortar containing Metamaterial bars (MMB) that were machined from SAE 1020 Carbon steel. Each MMB has a stepped geometrical shape, with a cylindrical bar divided into equal-length segments, along with a 'rise height' (p) change. Four geometries were defined, i.e., R0− Smooth bar, R1− p = 0.1mm, R2− p =0.3mm and R3− p=0.5mm. Three-point flexural strength tests were performed on the RCBs to determine the maximum bond strength (ML) between the MMB and cement mortar. Images of interfacial regions were obtained using SEM and 3D Roughness Reconstruction software to calculate the average roughness (Ra) and the roughness height (Rz). The reinforcement MMB geometry had a significant impact on the ML results, particularly on the first crack strength and the failure mode. The R3 geometry ML values were higher than the other tested geometries (44.5%). The results of the scale models are encouraging and offer a novel and prospective direction for further experimental and even numerical Metamaterial research to improve interfacial bond strength.

Bond Behavior of Auxetic Bars in Reinforced Concrete – A Numerical Study

“…In recent years, scientific studies have highlighted the significance of incorporating metamaterials as innovative technology in concrete. Among the notable research contributions are those by Mitchell et al (2014), Barri et al (2022), Mitchell, Pandolfi and Ortiz (2015), Ramírez et al (2022), Zhong et al (2022), Gupta et al (2023) and many others.…”