Interfacial Bond Adhesion Enhancement Mechanism Analysis of Self Stressing Alkali Activated Slag Concrete-Filled Round Steel Tube

Abstract

To investigate the interfacial adhesion behaviour and its enhancement mechanism of selfstressing alkali activated slag concrete-filled round steel tube, push-out samples, expansion performance test specimens, and SEM, XRD micro-test specimens were made with different dosage of calcium sulphoaluminate and calcium oxide expansive agent. The results show that the maximum interfacial adhesion stress is at 70-80 mm from the free end of the samples, and increases with the increase of the expansive agent dosage. The expansive agent such as calcium sulphoaluminate and calcium oxide can effectively reduce the drying shrinkage performance of the core concrete, and then improve the interaction between steel tube and core concrete. Microtest analysis results show that the main expansive source providing expansive power in the AASC system is Ca(OH).