Experimental investigation into bond characteristics of quartz sand modified enamel coated steel bar in concrete based on AE data

Acoustic emission (AE) is widely used in industries such as aerospace, petroleum, and construction. In civil engineering, especially for concrete structures, AE has been successfully utilized to detect concrete cracking, rebar corrosion, and bond characteristics between steel rebars and concrete. Recently, a quartz sand modified enamel (QSME) coating has been proposed to enhance the corrosion resistance and bond strength of steel rebars in concrete structures. This study focuses on the bond characteristics of QSME-coated steel rebars in concrete based on AE data collected during the tests. Concrete block specimens with steel bars coated with QSME embedded in the center were fabricated in the laboratory. Pull-out tests were conducted under both reversed cyclic and monotonic loadings. AE sensors were attached to the concrete surface to capture the energy released during the debonding process. For comparison, specimens with uncoated, enamel-coated, and epoxy-coated steel bars were also prepared and tested. Analysis of AE captured during the pull-out tests allowed to visualize the bond damage development during the tests and to differentiate between the behavior of the various rebar coating types. Results show that the AE activity released by QSME-coated rebar specimens was higher than that of uncoated, epoxy-coated, and enamel-coated specimens. This can be attributed to the enhanced chemical adhesion and interfacial friction between QSME-coated steel rebars and concrete.